Is IIT compatible with Russellian panpsychism?

Hedda Hassel Mørch (NYU / University of Oslo)

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Abstract: The Integrated Information Theory (IIT) is an empirically motivated theory of consciousness which entails a kind of panpsychism. In this paper, I discuss whether IIT is compatible with Russellian (or dual-aspect) panpsychism which has recently been defended in philosophy of mind. I will show that if IIT were compatible with Russellian panpsychism, this would contribute to solving Russellian panpsychism’s combination problem. However, the theories aren’t compatible as they currently stand, in view of what I call the coarse-graining problem. I will explain this problem, and offer two possible solutions. One solution involves a modification of IIT’s Exclusion postulate; another involves a modification of its coarse-graining principle.

1. Introduction

Panpsychism is the view that every physical thing is associated with consciousness. More precisely, it’s the view that every physical thing is either (1) conscious, (2) made of parts which are all conscious, or (3) itself forms part of a greater conscious whole. Humans and animals (or certain areas of human and animal brains) are conscious in the first sense, and panpsychists typically think fundamental particles, such as quarks, are conscious in this sense too. Artifacts and arbitrary aggregates, such as tables, chairs and heaps, are typically regarded by panpsychists as conscious only in the second sense, in virtue of being made of conscious particles. Particles and neurons that form part of human and animal brain areas which are conscious in the first sense are perhaps only conscious in the third sense. By “consciousness”, panpsychists mean phenomenal consciousness, i.e., the property of having some form of subjective, qualitative experience, or of there being something that it’s like for something to exist.[1]

Panpsychism has recently received new attention in both philosophy and neuroscience. In philosophy of mind, it has been argued that a version of panpsychism, panpsychist Russellian monism (named after Bertrand Russell, for reasons that will be explained below), is able to avoid the most serious problems that confront the traditional main positions in the field, physicalism and dualism (Nagel 1979; Strawson 2006; Alter and Nagasawa 2012; Chalmers 2015). For physicalism, this is the problem of the epistemic gap – aspects of which are highlighted by the knowledge argument (Jackson 1982, 1986) and the conceivability argument (Kripke 1980; Chalmers 1996). For dualism, it’s the problem of mental causation (Kim 1988; Papineau 2001).

In neuroscience, the Integrated Information Theory of consciousness (IIT) (Tononi 2004, 2008, 2011; Tononi, Albantakis, and Oizumi 2014) is a new fundamental theory of consciousness which has proved to have significant explanatory and predictive power. According to IIT, consciousness is correlated with integrated information, also referred to as Φ. Information in IIT measures the extent to which a system causally constrains its own immediate past and future state,[2] and integration measures the extent to which this information depends on the causal interconnectivity of the system’s parts.[3] Since even fundamental particles, such as protons and neutrons, [4] have a small amount of Φ (Koch 2012: 132), IIT entails panpsychism in the sense defined above.[5]

IIT sometimes encounters the objection that although it may appear to account well for empirical data about human consciousness – such as the absence of consciousness during deep sleep, general anesthesia, epileptic seizures, and in regions of the brain such as the cerebellum, all of which correlate with low values of Φ (Tononi and Koch 2015) – it can’t be correct because panpsychism is absurd (Searle 2013). But if Russellian panpsychism solves the main philosophical problems of consciousness, IIT’s panpsychism should be regarded as a feature, not a bug. IIT could claim philosophical support in virtue of being the only current neuroscientific theory compatible with the solution to the mind-body problem.

But not everyone agrees that Russellian panpsychism solves the mind-body problem. The main objection to Russellian panpsychism is based on the so-called combination problem (James 1890; Seager 1995).[6] The combination problem consists in explaining how complex consciousness, of the kind we know from our own case, could result from the appropriate combination of entities with simple consciousness, i.e., the particles that constitute our brain and according to panpsychism possess rudimentary forms of consciousness. According to the objection, the combination problem gives rise to further problems which are strongly analogous the main problems of physicalism and dualism (Goff 2006, 2009; Chalmers 2015, 2016).

At first glance, it appears IIT can help Russellian panpsychism solve the combination problem. The precise claim of IIT is that a system is conscious, in the first sense, if and only if it is a maximum of Φ, i.e., if the system has higher Φ than any of its own parts as well as any bigger system of which it forms part. This is IIT’s Exclusion postulate – consciousness does not overlap. This means that whenever the Φ of a system surpasses the Φ of the parts, the system goes from being conscious in the second, aggregative sense, to being conscious in the first, unified sense. This explains how mental combination occurs, at least in certain respects. Tononi and Koch imply (2015: 11, 13), somewhat contentiously, that IIT offers a complete solution to the combination problem in and of itself. But one might also regard IIT as a contributing factor to a complete solution, when taken together with other proposed solutions to the problem. Other proposed solutions include the phenomenal bonding view (Goff 2009, forthcoming) and the fusion view (Seager 2010, forthcoming; Mørch 2014). These proposals look promising in purely metaphysical respects, but both arguably fail to show what could possibly constitute an empirical correlate of combination. IIT shows what this correlate could be, namely maxima of Φ.

Unfortunately, however, a solution to the combination problem in terms of IIT is not straightforward. In order to solve the combination problem, IIT needs to be compatible with Russellian panpsychism, not just panpsychism in general. Panpsychism could also be combined with dualist or physicalist metaphysics,[7] but will then have no particular advantage compared to standard physicalism or dualism with respect to the mind-body problem. And there are some indications that IIT is only compatible with dualist or physicalist panpsychism. This would be bad news for both IIT and Russellian panpsychism: IIT could no longer claim that its panpsychism is in fact a philosophical advantage, and Russellian panpsychism would retain its combination problem.

In this paper, I will explain what indicates this disappointing result, and argue that it mainly derives from what I will call the coarse-graining problem. I will show that this isn’t a surface problem: IIT and Russellian panpsychism are in fact incompatible as the theories currently stand. But the conflict could still be resolved with the introduction of some substantive new principles. I will suggest two candidates for such principles; one involves a modification of IIT’s Exclusion postulate (not abolition, as some have called for (Schwitzgebel 2015)); another involves a modification of IIT’s principle for determining the spatio-temporal grain of conscious systems. My arguments, if successful, will not support a fully satisfactory solution to the combination problem in terms of IIT, but they should give reason for optimism and motivate further research into this approach.

I will begin by explaining the metaphysics of Russellian panpsychism and the combination problem in more detail. Then I will discuss how IIT could help with the combination problem, either on its own, or combined with the phenomenal bonding or fusion view. Then I will present the coarse-graining problem, which shows that the views are in fact incompatible, followed by my two proposals for how to resolve the problem.

2. Physicalism, Dualism and Russellian Panpsychism

According to Russellian panpsychism, consciousness is correlated with every physical thing in virtue of constituting the intrinsic nature of physical relational structure. As Bertrand Russell noted (1927), physics (or the physical sciences) describes only relational or structural properties – how physical things relate to other things, but not what they are like in and of themselves. These are the kind of properties which can be described in the austere language of mathematics. The phenomenal properties of consciousness, in contrast, seem to be intrinsic – we know what they are like in and of themselves, independently of how they relate to other things. According to Russellian panpsychism, structural properties need non-structural realizers, and relations need relata with intrinsic properties. Furthermore, phenomenal properties are the only intrinsic properties we know to exist. Russellian panpsychists infer from this that consciousness could be the realizer of all physical structure, or an intrinsic property of every entity described by physics in relational terms (Seager 2006; Alter and Nagasawa 2012).

As noted, the main attraction of Russellian panpsychism is that it offers a solution to the mind-body problem which appears to avoid the main difficulties of physicalism and dualism at once. Physicalism is the view that phenomenal (i.e., conscious) properties are identical to, or constituted by, physical properties – where physical properties are understood as the kind of properties that physics (or the physical sciences) describes. Its main problem is that it appears impossible in principle to see any entailment from the existence of physical properties to the existence of any phenomenal properties – something which should be possible if the latter were indeed identical to or constituted by the former (Chalmers 2003) (and we understand the nature of both the mental and the physical, see Goff (forthcoming)). In the absence of such an entailment, we’re able to conceive of the mental and the physical coming apart, as the conceivability argument (i.e., zombie argument) highlights (Chalmers 2009). Also, someone who knows all physical properties would not be able to deduce the existence and nature of mental properties, as the knowledge argument highlights (Jackson 1982).

Dualism is the view that phenomenal properties are distinct from physical properties, and are causally generated or affected by them. Its main problem is the threat of epiphenomenalism, because there is no non-redundant causal role for non-physical properties if the physical world is causally closed. The principle of physical causal closure is the principle that every physical event (that has a cause) has a sufficient physical cause. This has solid empirical and methodological support (Papineau 2001). It seems implausible that some physical events are systematically overdetermined by both mental and physical causes and, in any case, overdetermination still renders the mental redundant. The final option for dualists who accept causal closure and deny overdeterminism is to deny the causal efficacy of the mental and embrace epiphenomenalism.

Russellian panpsychism avoids physicalism’s main problem because it doesn’t say that phenomenal properties are identical with or constituted by physical properties. Instead, there is a sense in which phenomenal properties constitute physical properties, as their intrinsic realizers. If physical properties are structural properties, then there is in fact an entailment from the existence of phenomenal, intrinsic properties to the existence of physical properties – if some entities with intrinsic properties exist, then they necessarily stand in some relations and form some structure (though we can’t say a priori which structure).[8]

Russellian panpsychism avoids dualism’s main problem because this inverted constitution relation does not result in epiphenomenalism. If phenomenal properties realize physical structure, they are essential to the physical world. Causally efficacious physical properties can’t even exist without realizers or intrinsic properties. At the same time, this hypothesis leaves physical structure unchanged. Therefore, the physical world remains causally closed from the structural point of view. Russellian panpsychism can therefore respect the scientific considerations that support physical causal closure.

3. The Combination Problem

The combination problem is the problem of explaining how complex consciousness, of the kind we know from our own case, can result from the combination of simple entities with simple consciousness. Constitutive panpsychism is the view that complex consciousness is constituted by simple entities with simple consciousness, or, in other words, that complex consciousness is nothing over and above a collection of simple conscious experiences causally and/or spatiotemporally related in a certain way. This view faces a problem analogous to physicalism’s problem of the epistemic gap: it appears impossible in principle to see any entailment from the existence of entities with simple micro-consciousness – in any purely spatiotemporal or causal relation – to the existence of complex macro-consciousness. This can be illustrated by panpsychist versions of both the conceivability argument and the knowledge argument – think of micro-phenomenal zombies (Goff 2009) or a physically and micro-phenomenally omniscient Mary (Chalmers 2016).

Emergent panpsychism is the view that complex consciousness is distinct from micro-consciousness causally and/or spatio-temporally related in a certain way, but is rather causally generated by micro-conscious configurations. This view faces a problem of macro-mental causation analogous to dualism’s problem of mental causation: macro-consciousness appears causally and explanatorily redundant[9] assuming that micro-consciousness already realizes all physical structure. Positing additional structure for which distinct macro-consciousness could be the realizer would bring emergent panpsychism into conflict with the principle of physical (or at least microphysical) causal closure.

In this way, the combination problem threatens to undermine the motivation for Russellian panpsychism. It appears to show that the view doesn’t avoid the problems of physicalism and dualism after all; it merely moves them, and has them reappear in a different guise.

4. IIT and the Combination Problem

IIT is a theory with both empirical and metaphysical aspects. On the one hand, it proposes an empirical correlate of consciousness: all and only conscious systems are maxima of Φ. On the other hand, it aims to explain why this correlation holds. Tononi argues that the correlation follows a priori from a set of phenomenological axioms, truths about consciousness which are self-evident upon introspection (Tononi, Albantakis, and Oizumi 2014).

The correlational claim, that maximum Φ is the correlate of consciousness, is empirically verifiable in principle. Although Φ can be precisely calculated for complex systems only in theory; insofar as it can be estimated, it predicts which kinds of alterations in the brain would lead to a loss of consciousness (namely those that reduce the Φ of a brain area below the Φ of its parts). It’s also verifiable in terms of how well it accounts for pre-existing data about consciousness. IIT accounts for why an area of the brain such as the cerebellum is not conscious, even though it has more neurons than the cerebrum; why epileptic seizures, as well as deep sleep, lead to loss of consciousness even though neural activity remains high or increases; and a number of other facts that puzzle neuroscientists.[10] Other proposed correlates of consciousness, such as activation in specific brain areas, electrical activity within some particular range, or the P300 wave, all seem to be absent in some clearly conscious states (Tononi and Koch 2015: 3-4).

The explanatory claim, that the correlation follows a priori from phenomenological axioms, is supported by appeal to philosophical argument only. If the explanatory claim is correct, then IIT would solve the combination problem on its own. The a priori connection would eliminate all epistemic gaps, and the Exclusion postulate eliminates the problem of causal exclusion (this will be discussed in more detail below). The philosophical case for the explanatory claim is, however, somewhat contentious.[11] It’s worth considering, therefore, whether the empirically verifiable, purely correlational claim could support a solution to the combination problem without commitment to the explanatory claim. I will suggest two ways in which the correlational claim can be combined with metaphysical approaches to combination that have been developed independently of IIT.

The phenomenal bonding view (Goff forthcoming) is a proposal for a solution to the combination problem for constitutive panpsychism. According to this view, some physical (i.e., spatial, temporal and/or causal) relations have their own intrinsic nature which is not reducible to the intrinsic properties of their relata. Physics is silent about the intrinsic nature of these relations, just as it is silent about the intrinsic nature of physical relata. Via introspection, we have access to the intrinsic nature of some physical relata (i.e., the intrinsic, phenomenal properties of our own brains), but we don’t have access to the intrinsic nature of physical relations. According to the phenomenal bonding view, if we knew the intrinsic nature of the kind of relation that connects the particles in our brain, we would see that the existence of macro-consciousness is indeed entailed by the existence of micro-conscious thus related.

One of the main challenges for the phenomenal bonding view is to specify what physical relation the phenomenal bonding relation might correspond to (Chalmers 2016). The phenomenal bonding relation must be a physical relation which holds within all and only systems where it’s plausible that mental combination takes place. Goff suggests that the spatial relation is the phenomenal bonding relation. This would entail that all phenomenal properties which are spatially related are also co-conscious – experienced together from a single subjective point of view – so that every thinkable object (group of particles) is conscious (in the first sense). Most panpsychists reject this kind of universalism – they want to restrict unified consciousness to just some kinds of systems, including brains and other organs (or organisms), and perhaps also lower level natural objects like minerals or molecules, and/or certain kinds of computers or robots, etc. There is no obvious candidate for a physical relation which gives this result.

IIT tells us what the phenomenal bonding relation could be. If maximal Φ is the correlate of unified consciousness, then the phenomenal bonding relation would be equivalent to a certain kind of causal relation: causal relations that relate elements within systems that have more Φ than overlapping systems. One might wonder why the intrinsic nature of causal relations would depend on whether or not they are part of systems with maximal Φ.[12] But the most important thing for the phenomenal bonding view is that there exists some natural, or at least not wildly disjunctive and ad hoc, kind of physical relation, which does not entail universalism, and that could possibly be identified as the phenomenal bonding relation.

The fusion view (Seager 2010, forthcoming; Mørch 2014) is an approach to the combination problem for emergent panpsychism. According to this view, the emergence of macro-consciousness is not synchronic – emergent macro-consciousness doesn’t exist on top of, and at the same time as, underlying micro-consciousness. Rather, the emergence is diachronic – emergent macro-consciousness succeeds and replaces the set of micro-phenomenal properties that gives rise to it. The generation of macro-consciousness happens as fusion: under certain conditions, micro-phenomenal properties fuse or blend together to form a new macro-conscious unity. The fusion view avoids the problem of macro-mental causation: if macro-consciousness replaces micro-consciousness (i.e., micro-consciousness transforms into macro-consciousness), it’s the sole candidate realizer for the physical properties with which it is correlated. It’s hard to see how a synchronic emergence view can get around the same problem.

The main challenge for the fusion view is to find a physical correlate of mental fusion. Seager (2010, forthcoming) claims that quantum entanglement and the formation of black holes are physical examples of fusion. In both entangled systems and black holes, the constituents lose their individuality and are supplanted by an irreducible new unity – a “large simple”. But nothing like this seems to be going on in the brain. I have argued (Mørch 2014) that mental fusions don’t need to be partless simples, they only need to be wholes which are metaphysically prior to their parts. Fusions also don’t need to look like unities from the physical point of view in order to have this metaphysical structure, although it would be somewhat odd if they didn’t.

IIT is in itself a kind of fusion view. According to the Exclusion postulate, only maxima of Φ are conscious, hence whenever a complex system becomes conscious by gaining maximal Φ, its parts will lose micro-consciousness (in the first sense; but they will remain conscious in the third sense, as defined in the introduction). Φ measures not only information but also integration, and integration is a form of unity.[13] IIT thus defines a sense in which physical systems can be more unified than their parts, and thereby be said to be metaphysically prior to their parts, as fusions should be. Now, one might wonder whether fusions shouldn’t ideally be characterized by even stronger markers of unity.[14] But the most important thing for the fusion view is that there is some property which could serve to identify fusions from the physical point of view, which is empirically detectable, but does not entail any revisionary physical hypotheses (such as quantum entanglement at the brain level, or other kinds of strong physical emergence).

5. The Coarse-Graining Problem

Unfortunately, there is a problem which gets in the way of any solution to the combination problem in terms of IIT: the coarse-graining problem. This problems stems from the way IIT identifies the spatiotemporal grain of consciousness.

IIT not only selects a set of elements which regarded as a system gives maximal Φ. It also selects a spatiotemporal grain (Hoel, Albantakis, and Tononi 2013). One might regard the brain (or brain area that correlates with consciousness) as a system consisting of elements at the smallest spatial grain – as a system of subatomic particles at the nanometer scale or below. Calculating on this basis will result in certain value Φ. But one might also regard the brain as a system consisting of elements at a coarser spatial grain – such as a system of neurons or groups of neurons. This will result in a much higher value of Φ. One can also vary the temporal grain. One can regard the system as proceeding from state to state at the rate of a nanosecond, and calculate how much integrated information the system has about the immediate past and future nanosecond. Or one can regard each state as lasting for milliseconds, and calculate how much integrated information each milliseconds-long state has about the immediate past and future milliseconds long states. For the brain, a coarser temporal grain (most likely corresponding to the time it takes for neurons to fire) will result in much higher Φ.

If a maximally integrated system exists at a certain spatiotemporal grain, the structure below that grain won’t matter to the quality of the experience of that system (Tononi and Koch 2015: footnote 9). For this reason, IIT allows for multiple microphysical realizability of systems with identical consciousness. If the Φ of the brain peaks at the spatial grain of neurons, it won’t matter to the character of its experience whether the microstructure of the neurons is carbon-based or silicon-based as long as they function identically at the neuron level.

This leads to a conflict with Russellian panpsychism, as follows. Every major theory of causation entails that the causal structure of the world is determined by the intrinsic properties of things together with the laws of nature.[15] According to the causal powers view (Shoemaker 1980; Ellis 2001; Bird 2007), the causal structure of the world is determined by the intrinsic, or intrinsically grounded, causal powers (or dispositions) of individual things (these powers in turn determine the laws).[16] According to realism about laws (Dretske 1977; Tooley 1977; Armstrong 1978), the causal structure of the world is determined by irreducible governing laws, and it’s natural to think that the laws apply to things in virtue of their intrinsic properties.[17] According to the regularity theory (Hume 1739-40; Lewis 1973), the causal structure of the world is brute, i.e., not determined or explained by anything else. But it is constituted by regularity relations (across the actual or the closest possible worlds) between things with intrinsic, qualitative properties.

Russellian panpsychism claims that the intrinsic properties of things are all phenomenal properties. Combined with any of the above views about causation, it follows from this that physical structure at least nomologically supervenes on phenomenal properties. That is to say, given that the laws of nature (whether irreducible, derived from intrinsic powers, or reducible to contingent regularities) remain the same, then how things behave and what relational structures they thereby form, is determined by what they are intrinsically like, i.e., their phenomenal properties.

If physical structure nomologically supervenes on the phenomenal properties of things, then there can’t be systems with different physical structure but identical phenomenal properties, given the same laws. But according to IIT, neuron and silicon brains, which would have different microphysical structure, could have identical phenomenal properties, given the same laws. It follows that Russellian panpsychism is false – physical structure doesn’t nomologically supervene on phenomenal properties.

One might think the conflict can simply be resolved by saying that although silicon brains and organic brains have identical macrophenomenal properties, they have different microphenomenal properties. Silicon neurons (or molecules/atoms) would have silicon-type micro-experience, while the organic neurons (or molecules/carbon atoms) would have different carbon-type micro-experience, while both constituting the same human macro-experience. The identical human macro-experiences realize, or nomologically determine, identical coarse-grained macrophysical structure, but the different neuron (or molecule/atom) experiences will realize the different microphysical structures.

But this is ruled out by IIT’s Exclusion postulate, according to which consciousness never overlaps – only the system with maximal Φ is conscious. Neurons (or molecules/atoms) can’t have different experiences if they are excluded from having experiences of their own in the first place. Hence, IIT is not compatible with Russellian panpsychism in view of the coarse graining principle and the Exclusion postulate.

It might seem, then, that the best way of rendering IIT and Russellian panpsychism compatible would be to abandon one of these principles. But abandoning either leads to both philosophical and empirical problems.

6. Abandoning Exclusion

Rejecting Exclusion leads to a prima facie very undesirable proliferation of consciousness (but see Schwitzgebel 2015 for an argument for abandoning Exclusion in spite of this). Nations, the internet, the galaxy and the universe all have non-zero, but non-maximal, Φ and would therefore be conscious without Exclusion. There would also be multiple overlapping consciousnesses within the brain. Not only would each neuron be conscious, there would also be one consciousness associated with almost any combination of neurons (the brain, the brain minus one neuron, minus two neurons, minus two other neurons, and so on). In other words, we get a serious case of the problem of the many. For those who are motivated to combine IIT with Russellian panpsychism in order to avoid universalism with respect to phenomenal bonding, this consequence should be unacceptable.

Rejecting Exclusion is also empirically problematic for IIT. As mentioned, the empirical case for IIT is largely based on data about when our (waking or dreaming) consciousness disappears and reappears according to reports, such as deep sleep, general anesthesia, seizures and coma. These states don’t leave the brain with zero Φ – our consciousness disappears (i.e., disintegrates into multiple lesser consciousnesses) long before Φ reaches zero. What explains this? Officially, IIT is not entirely clear on this point. One possible explanation is that low, non-maximal but non-zero, Φ still correlates with some dim form of consciousness, but not with memory or reportability.[18] But this seems somewhat ad hoc – why would it necessarily be the case? It could also be very worrisome if true about anesthesia![19] An alternative, more systematic explanation would be to appeal to the Exclusion postulate: our consciousness disappears because the Φ of the normally conscious brain area goes below the Φ of neurons, neuron groups, or other subsystems that constitute it. Given Exclusion, these subsystems will become individually conscious instead (each to a much lesser degree) because they are now the maxima. It’s not clear whether the Φ of sleeping or anesthetized brain areas is actually lower than the Φ of any subsystems – given the practical difficulties with measuring Φ precisely, this is still an open empirical question. But by abandoning Exclusion, the simple and elegant explanation based on this conjecture is in any case ruled out. In view of these problems, abandoning Exclusion in order to render IIT compatible with Russellian panpsychism looks like it won’t be worth the costs.

7. Abandoning Coarse-Graining

Instead of Exclusion, one could consider abandoning coarse-graining. This would mean that when calculating the Φ of a system, one should always regard it as a system of fundamental particles. If so, silicon and organic brains would have different experiences, on which their different micro-structures could nomologically supervene.

But abandoning coarse-graining also leads to both philosophical and empirical problems. Firstly, when we look at our own experience, it appears, phenomenologically, to have a certain spatiotemporal grain. The structure of our experience appears to be much more coarse-grained than the microphysical structure of our brain. At any moment, we don’t seem to experience as many distinctions within our experience as there are particles in our brain. It also seems that our experiences last much longer than the shortest microphysical events in the brain. Experiences seem to last for at least some milliseconds, but microphysical events in the brain last nanoseconds or less.

This is the basis for the so-called grain problem in philosophy of mind known from Lockwood (1993) and Sellars (1965, 1971): the grain of experience doesn’t correspond to the microphysical grain of the brain. The conclusion often drawn from the grain problem is that human consciousness needs an irreducibly macrophysical correlate, which is precisely what it gets with IIT’s coarse-graining principle, but loses without it.

Secondly, rejecting coarse-graining gives an empirical problem. As noted, if we regard the brain as a system of particles, it will have lower Φ than if we regard it as a system of neurons. And it will also have lower Φ than individual neurons, molecules or atoms in the brain. Therefore, without coarse-graining, neurons, molecules or atoms will be conscious, not the brain (or any extended brain area) as a whole. This would result in billions (or more) other consciousnesses in our brains, each of which as highly conscious as our own. This seems very implausible (as another version of the problem of the many, although in this case the many don’t spatially overlap) and doesn’t fit any natural interpretation of empirical data. With coarse-graining, in contrast, Φ will peak only in a few locations, and the highest peak would be much higher than the others, so there will only be one most advanced consciousness in the brain.[20]

Hence, abandoning coarse-graining seems out of the question for IIT. What I will now suggest, is that in order to render IIT compatible with Russellian panpsychism, there is no need to wholly abandon either the coarse-graining or the Exclusion postulate. Instead, it would suffice to merely modify either one of the principles, in ways I will now describe.

8. Modifying Exclusion

One way of avoiding the coarse-graining problem is to modify the Exclusion postulate by relativizing it to spatiotemporal grains. Instead of saying that consciousness never overlaps, IIT could say that (1) consciousness never overlaps within the same spatiotemporal grain, and (2) there is consciousness only at grains where Φ is higher than any other level below. This would entail that the brain, as a coarser-grained system, will have overlapping consciousness at the finest, microphysical grain (since there is no level below, clause (2) is vacuously satisfied by the finest grain). In two brains with different fine-grained parts, such as carbon and silicon atoms, these parts will have qualitatively different consciousness. Differences in microphysical structure could then nomologically supervene on these differences in microconsciousness.

This relativized Exclusion postulate avoids the problems that result from wholly abandoning it. It won’t prevent human consciousness from disappearing in deep sleep, general anesthesia and so on before Φ goes to zero. Human consciousness would disappear when the Φ of its correlate brain area goes lower than the Φ of individual neurons or neuron groups, because Exclusion is still in effect within this grain. If the brain has maximal Φ all grains considered, there will be no internet, galaxy or cosmic consciousness. The internet, the galaxy or the cosmos will not have higher Φ than the brain if we regard them as systems made of neurons and other entities at the grain of the brain. Nor will they have higher Φ than the brain if we regard them as systems made of coarser-grained parts such as computers or stars (but if they did, they could have consciousness without threatening to eliminate human consciousness via Exclusion). Below the brain level, there could be grains above the subatomic that increase Φ before the grain of the brain, resulting in more than one level of microconsciousness, but there won’t be arbitrarily or absurdly many such levels.

This modification of Exclusion is only compatible with constitutive Russellian panpsychism. If microphenomenal and macrophenomenal properties are entirely distinct, as per the­­­ emergent view, then micro-phenomenal properties at lower grains would causally exclude macro-phenomenal properties at higher levels with maximal Φ. However, the idea that coarse-grained phenomenal properties are constituted by overlapping fine-grained phenomenal properties seems to lead to another problem. Say I have an experience of a tiny patch of phenomenal green, the smallest patch of green that is possible given the grain of my experience. This green patch will be completely uniform green for me, because my experience can’t contain any complexity below its own smallest grain. Now, this uniform green patch will actually be constituted by micro-phenomenal properties at a smaller grain, for example even smaller patches of blue and yellow that are the experiences of the particles in my brain (or some other kinds of particle experiences that we can’t imagine). But then it seems my experience of green is both uniform and partless, and complex, made of blue and yellow (or at least non-green) parts, at the same time.

Many Russellian panpsychists, and non-reductionists about consciousness in general, are motivated by the principle that there is no appearance/reality-distinction for phenomenal properties (if an experience appears to be of green, then it is of green, phenomenally speaking). If so, it would be contradictory to say that the same phenomenal properties can appear either uniform green or complex yellow/blue (or otherwise non-green) depending on the grain. Hence, this way of rendering IIT and Russellian panpsychism comes at the cost of introducing a kind of appearance/reality distinction for phenomenal properties, and the consequences of this would need to be examined in more detail in order to see if that could possibly be acceptable.

9. Modifying Coarse-Graining

My second suggestion is to modify the coarse-graining principle, in a way that starts from noticing a certain tension between two aspects of the combination problem.

The grain problem, as already mentioned, says that macro-consciousness has too little structure to reflect the full microphysical structure of our brains. But there is also an aspect of the combination problem, known as the palette problem (Chalmers 2016: section 7). According to this problem, macro-consciousness has too many qualities. In physics, we find a limited number of fundamental particles (about 17, according to the standard model). This suggests a correspondingly limited number of basic micro-phenomenal qualities. In our experience, however, we find what appears to be an endless number of different phenomenal qualities (colors, sounds, emotions and so on). It’s hard to see how all these qualities can result (without radical emergence) just from combining a small number of basic micro-phenomenal qualities in different ways.

If macro-consciousness has too little structure, but too many qualities, to reflect its microphysical correlate, this suggest that the missing structure is somehow encoded in the extra qualities – that microphysical structure is reflected in macrophenomenal qualities as opposed to macrophenomenal structure. Instead of having one little distinct patch in our experience corresponding to every particle in the brain, perhaps a single coarse-grained quality (like a field of color, or an emotion) reflects complex microphysical structure in virtue of the many complex ways in which it is different from other possible macrophenomenal qualities.

This would result in a modified coarse-graining principle for IIT: information below the grain where Φ peaks matters to the quality, but not the structure, of experience. In other word, macrophenomenal structure will be multiply microphysically realizable,[21] but macrophenomenal qualities will not be. If your organic neurons were to be replaced by functionally identical silicon neurons, then your experience would have the same (contrastive and motivational) structure, but different qualities (i.e., a shifted spectrum). For example, for the silicon consciousness, tomatoes and grass will be experienced as having color-like qualities we cannot imagine, but they will be as different from each other as red and green are for us, and they will have pain and pleasure-like qualities which feel different from ours, but they still feel equally bad and good. The fact that silicon and organic brain have the same macrophenomenal structure could account for why these systems will show the exact same behavior at the macrolevel. That they have different, shifted qualitative spectra could perhaps account for why they have different micro-level dispositions (why they respond differently to microscopic measurement and decompose in different ways).

Many questions remain as to precisely how microphysical structure can be encoded or grounded in unstructured qualities. I have only shown that there is some extra qualitative information in one place that can be connected to missing structural information in another place, and there is nothing that immediately rules out that there is some way of translating one to the other. In this way, it no longer looks impossible for IIT and Russellian panpsychism to be combined.

10. Conclusion

I have suggested two ways of solving the coarse-graining problem and rendering IIT and Russellian panpsychism compatible. These suggestions involve substantive modifications of some basic principles of IIT, either the Exclusion postulate or the coarse-graining principle. With one of these modifications, IIT would support (significant progress towards) a solution to the combination problem for Russellian panpsychism – either on its own, in view of the explanatory claim according to which the principles of mental combination are a priori deducible from phenomenological axioms, or on the basis of its correlational claim only, in combination with either the phenomenal bonding view or the fusion view of mental combination.

Both my suggested modifications come at a price. The suggested modification of the Exclusion postulate is in tension with the view that phenomenal qualities necessarily are as they appear. The suggested modification of the coarse-graining principle assumes mysterious links between qualities and structure. Perhaps the mystery of the latter proposal is preferable to the tension resulting from the former. A modification of the Exclusion postulate might also be more at odds with Tononi’s own philosophical case for IIT.

IIT has many philosophical aspects which have not been discussed here – as noted, I have set the theory’s central philosophical claims mostly aside and mainly considered the significance of its in principle empirically verifiable correlational claim, i.e., the claim that maximal Φ is the correlate of consciousness. IIT as a whole should be subjected to closer philosophical scrutiny if the theory is to fully support a solution to the combination problem. On the one hand, one might find even more sources of tension with Russellian metaphysics within IIT. On the other hand, one might discover other aspects of IIT that could contribute to even further advancing the case for a panpsychist solution to the mind-body problem.[22]


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[1] Consciousness does not require the capacity for, e.g., thought, abstraction or self-awareness. These can be regarded as advanced, complex forms of consciousness and reserved for advanced, complex physical systems. Therefore, panpsychism does not entail that particles think or are self-conscious.

[2] I.e., how much can you know about the previous state of the system only by looking at its present state, given that all external influences are fixed (given that you know all the relevant causal laws)? And how much can you know about the next state of the system, fixing external influences? Or, in other words, to what extent do the causes and the effects of a system reside within the system itself?

[3] I.e., how much information would you lose by cutting the system in half? Computers, of the kind we make today, might in principle have the same quantity of information as human brains. But in a computer, each transistor is connected to just a few other transistors. In the brain, the neurons are connected to a vast number of other neurons. If you cut a brain in half, you are therefore going to lose a lot more information than if you cut a computer in half. This shows that the brain has a much higher level of integrated information (Φ) and therefore more consciousness. (In fact, according to IIT’s Exclusion postulate, the computer will probably not be conscious, in the first sense, at all, only its parts will be, because its Φ will probably not be high enough to supersede the Φ of its parts.) For a more detailed introduction to IIT, see, e.g., Tononi et al. (2016) and Tononi and Koch (2015). For a full description of the latest version of the theory, see Tononi, Albantakis, and Oizumi (2014).

[4] It should be noted that simple fundamental particles, such as quarks, can only (unless they turn out to have internal structure) be conscious only in the third sense given IIT. Since they have no complexity, they will have zero Φ. But quarks are never found in isolation, they always form part of structured particles (e.g., protons) which have some Φ and hence some consciousness.

[5] Tononi and Koch (2015) are careful to distinguish IIT’s form of panpsychism from the form of panpsychism that says that all things, including artifacts and aggregates, are conscious in the first sense, as opposed to in just the second or third sense.

[6] The most common objection to panpsychism is probably “the incredulous stare”. The most serious objection is the combination problem.

[7] Dualist panpsychism would be the view that every physical thing is connected with a mental substance or has wholly non-physical mental properties via fundamental psychophysical laws of nature. Physicalist panpsychism would be the view that consciousness is to be reductively identified with a ubiquitous physical property (such as integrated information understood in a purely functionalist way).

[8] The entailment also goes the other way around. If we accept that structure needs intrinsic realizers, and that phenomenal properties are the only intrinsic properties we know, then there is an entailment from the existence of physical properties to the existence of either phenomenal properties or unknown properties of a similar nature (non-panpsychist Russellian monists prefer the latter alternative).

[9] Perhaps outright excluded: overdeterminism is perhaps not even an option for emergent panpsychism, because one structural property can’t have two distinct mental realizers (micro-phenomenal properties plus an emergent macro-phenomenal property).

[10] The cerebellum has low Φ in spite of having many neurons (Tononi 2008: 221); under epileptic seizures and deep sleep Φ strongly decreases even though activity increases or remains high (Tononi 2008: 223).

[11] Some complain that the alleged phenomenological axioms are less than self-evident (Cerullo 2015). One might also complain that it’s not self-evident how to translate the phenomenological axioms into empirical postulates. There might also be multiple ways to translating the empirical postulates into a mathematical formula (Tegmark 2016). Chalmers (2016) claims that IIT is best seen as a providing a fundamental, a posteriori law of nature specifying when combination occurs, but he does specify the precise point he thinks Tononi’s a priori justification fails.

[12] Chalmers notes (2016: section 6.3) that relations along the lines of IIT could be the phenomenal bonding relation, but objects that these relations are derivative and not fundamental. He claims that a solution to the combination problem in terms of phenomenal bonding and something like IIT get a new combination problem: how do fundamental causal relations (proto-bonding relations) become phenomenal bonding relations when they take on IIT-like character? A phenomenal bonding theorist could perhaps respond by renewed appeal to our ignorance of the intrinsic nature of physical relations: if we knew the intrinsic nature of causal relations, we would see how iworks.

[13] Recall, high integration means that the parts of a system are highly causally interconnected. In this way, it’s bound together as a unit.

[14] Tononi claims that maximal Φ corresponds to maximal causal power. This would give fusions a very strong form of metaphysical priority, without strong emergence of the kind that violates microphysical causal closure. But the view that Φ corresponds with causal power depends on a controversial metaphysical view about causation (Hoel, Albantakis, and Tononi 2013).

[15] Insofar as things are taken to have intrinsic properties at all – theories such as structural realism (Ladyman and Ross 2007) deny this, but this is incompatible with both Russellian panpsychism and IIT which take consciousness to be intrinsic.

[16] The causal powers view would not be compatible with Russellian panpsychism, which takes phenomenal properties to be categorical (i.e., non-dispositional), if dispositions are regarded as having no categorical aspect or as being absolutely fundamental, i.e. not grounded in intrinsic categorical properties. But Russellian panpsychists are free to adopt the view that dispositions have a categorical aspect (Martin and Heil 1999; Strawson 2008) or to regard dispositions as intrinsic in virtue of being grounded in intrinsic categorical properties/aspects.

[17] Armstrong explicitly holds that laws of nature consist in relations between categorical, i.e., intrinsic and non-dispositional, universals. It’s hard to say how laws could apply to things in virtue of their extrinsic properties, since most extrinsic properties would be determined by the laws, which means things could not possess them unless the laws already apply. Laws could perhaps apply to things in virtue of their bare spatiotemporal locations, but this seems empirically false, if not also hard to make metaphysical sense of.

[18] Tononi and Koch (2015: 13) gesture toward such a view.

[19] Although one might think that consciousness during anesthesia is not painful, or if it is, that it’s just very dimly painful and therefore nothing to worry about – but none of this is obvious.

[20] At least usually – according to IIT, split brain (severed corpus callosum) patients will have one consciousness in each hemisphere, with almost the same Φ. It’s also possible that our consciousness temporarily splits into two in cases such as automatic (absent-minded) driving.

[21] According to Russellian panpsychism, there is a sense in which the mental realizes the physical. But there is also realization within the physical, in another sense of the term. To say that macroconsciousness in multiply realizable given Russellian panpsychism would really be to say that the macrophysical correlate of macroconsciousness is multiply realizable physically speaking, and while macroconsciousness realizes the macrophysical correlate metaphysically speaking.

[22] Many thanks to Erik Hoel and Giulio Tononi for helpful discussion of the issues raised in this paper, and for clarifying and explaining relevant aspects of IIT. I also thank all the participants of the workshop IIT: Foundational Issues (New York University, November 2015) for their comments.

12 thoughts on “Is IIT compatible with Russellian panpsychism?”

  1. Hedda argues that certain problems with Russellian panpsychism can be solved by joining the view with Integrated Information Theory (IIT), then identifies some problems with such a combined view, and finally suggests ways to resolve those problems. Russellian panpsychism holds that phenomenal consciousness is what physical theories describe mathematically, implying that all matter has consciousness in it; it faces a ‘combination problem’, concerning how to make good on the promise that spreading consciousness so liberally around the universe will help explain human consciousness. On the other hand, IIT connects consciousness with something called ‘information integration’ – in essence a sort of holistic mutual sensitivity among a system’s parts. Perhaps the two can help each other out: perhaps the basic consciousness present in material particles combines into humanlike minds when those particles come to integrate information? As Hedda shows, matters are not so simple.

    I think the project Hedda is pursuing is a good one: Russellian panpsychism is a promising theory of consciousness, and there’s a lot to gain from incorporating elements of IIT into its theory of combination. And I think Hedda is completely right about the incompatibility between the two views: given the Exclusion and Coarse graining, IIT just doesn’t allow for enough consciousness for it to play the role that Russellianism assigns to it, namely of underlying all physical structure (at all scales). However, I think there’s a lot of room for debate about which parts of IIT panpsychists should keep and which they should drop. So in this commentary I’m going to offer a critical voice on three parts of Hedda’s paper: how she sees the benefits IIT provides, which ways of making it fit Russellian panpsychism she rejects, and what to make of the way she eventually endorses.

    So first, what are supposed to be the benefits that IIT provides? Hedda notes two particular versions of panpsychism, which posit either some sort of bonding relation (which connects subjects in a way that explains their composing a composite subject) or a more radical fusion process (which gets rid of the parts as soon as the new whole is formed). Both of these versions of panpsychism say that there is a special moment when either bonding or fusion occurs, a transition from many into one (with or without the many continuing to exist). IIT provides an answer to the question ‘when is that special moment?’ – the bonding or fusing is meant to happen just when a new maximum of integrated information is formed. Now, this is a fairly modest sort of role for IIT, relative to the aims that its proponents usually give for it – IIT is not being called in to explain consciousness itself, but only to say where and how it’s distributed. While I agree with Hedda that IIT is much more plausible in this more modest role, I think that just taking it in this less-ambitious form can obscure some crucial questions about its significance.

    Take the key claim Hedda extracts from IIT: that consciousness correlates with maxima of integrated information. Is this an a priori truth, somehow true in virtue of the essential nature of consciousness or information, or is this a proposed law of nature, metaphysically contingent and epistemically a posteriori? If it’s the latter, then it’s not at all clear that Russellian panpsychists should be eager to sign up to it, because in a lot of respects it’s a very strange, rather inelegant, law. None of the laws of physics features anything like a ‘coarse-graining’ principle – indeed none of them even mention ‘grain’. They apply indifferently however we carve up the world, on larger or smaller scales, rather than privileging a specific scale. None has an ‘exclusion’ mechanism either (particles in a complex massive object don’t lose their mass in favour of the mass of the whole). None relies on assigning, to a macroscopic entity, a finite list of possible states it can be in, and then giving each of those states a precise probability.

    On the other hand, is consciousness-integrated information correlation meant to a priori. But then Russellian panpsychists couldn’t endorse it, at least if it’s ‘consciousness in general’ that is a priori correlated with integrated information. Russellian panpsychism treats consciousness as a fundamental building block, and is usually motivated by the inadequacy of all attempts to analyse consciousness a priori into some physical or structural notion. The only way I can see for IIT to have an a priori role in Russellian panpsychism is to hold out information integration as a correlate, not of consciousness per se, but of something like ‘complex consciousness’, consciousness whose structure or content or quality rises above the dim and unimpressive base-level consciousness possessed by fundamental particles. I think IIT is actually very well suited to a role like that, but it’s a much more modest role than either its usual proponents, or Hedda, want to give it.

    Next, I want to speak up in defence of some of the options that Hedda rejects – versions of the IIT/panpsychism marriage that abandon either Exclusion or coarse-graining (or modify Exclusion). In particular, two of the main reasons Hedda gives for rejecting these approaches seem to be themselves in tension with Russellian panpsychism. The first of these is the worry that abandoning the Exclusion postulate will enable a vast profusion of different consciousnesses: “Nations, the internet, the galaxy and the universe” would be conscious, not to mention the “multiple overlapping consciousnesses within the brain.” Now I can certainly see that on most theories of consciousness, it would be a mark against a view that it implied this kind of profusion. But surely for panpsychists that ship has sailed: panpsychists already accept far more consciousness than everyday thought does, even in things which do not to ‘seem conscious’ to humans. Once we’ve accepted that, I don’t see why we should bat an eyelid at further profusion, if it results from the simplest and most straightforward fundamental theory.

    A slightly more abstract way to put this point is as follows: Russellian panpsychism gets its appeal from knitting together consciousness and the physical world without attempting a direct reduction of one to the other. Just as the fundamental physical properties are present all throughout the universe, so too are the fundamental phenomenal properties. But when it comes to physical properties, we already face a vast profusion of overlapping entities (especially those involved in the ‘problem of the many’ that Hedda alludes to). And though we could always try to contort our metaphysics of physical objects to somehow ‘exclude’ all but a few of these from existence, it seems to me that the most sensible option is to learn to accept that profusion. And if we’re doing that for physical objects, and we like Russellian panpsychism for knitting together the phenomenal and the physical, why not just accept profusion of consciousnesses as well?

    I had similar doubts about Hedda’s suggestion that IIT-panpsychism without Exclusion would cease to explain why we lose consciousness during certain states of sleep and anaesthesia, where there is some plausibility in thinking that the brain’s integrated-information value drops. Of course, without Exclusion the brain’s integrated information can still drop, it just won’t cease to be conscious. Hedda considers the response that we need not assume the brain ceases to be conscious, since it might slip into a “dim form of consciousness [without] memory or reportability”, but rejects this as ‘ad hoc’. But surely panpsychists already posit ‘dim consciousness without memory or reportability’ in their conscious particles! And if what IIT is meant to help explain is, in part, the difference between our waking human consciousness (featuring memory and reportability) and that dim particle-consciousness, then surely it’s not ad hoc at all to say that the lower our integrated information gets, the closer our experience gets to that of a particle.

    In both of these cases, it feels like the best justification for rejecting nation-consciousness, or internet-consciousness, or consciousness even in anaesthetised patients, is the intuition that where there’s consciousness, there should be intelligent behaviour. But of course, Russellian panpsychists have to reject that intuition from the get-go. So I think there are more good options here that Hedda suggests: panpsychists who like IIT have multiple equally promising avenues available.

    Finally, what Hedda eventually endorses is to modify IIT’s ‘coarse-graining’ principle. Rather than saying (as its canonical form does) that only information on a certain optimal spatio-temporal scale (namely, the scale at which information is most integrated) makes a difference to consciousness, and information on smaller scales does nothing, the modified principle would say that information on the special scale makes a difference to the structure of experience, while information on smaller scales makes a difference only to its quality. This solves two problems at once – on the one hand, physical brain structure seems to have more complexity than human experience (the ‘grain problem’), and on the other hand, human experiences seems to have a far wider array of distinct qualities than physics provides (the ‘palette problem’). Hedda’s suggestion that “extra qualitative information in one place… can be connected to missing structural information in another place” seems to me to be definitely the most promising approach for panpsychists to adopt on these two problems.

    However, it’s not clear to me why this approach (call it the ‘two-birds-one-stone’ approach) wasn’t available to the views which abandon coarse-graining entirely, or modify the Exclusion principle, which Hedda earlier rejected for their struggles with the grain problem. There are certainly a lot of very perplexing issues that arise here – the difference between phenomenal structure and phenomenal quality, the sense in which consciousness cannot feature an ‘appearance-reality’ distinction, whether we should be comparing the number of “distinctions within experience” and the number of “particles in our brain”. But just working at a rough and preliminary level, if it makes sense for experiential detail to be sometimes present as discernible structure and sometimes as a change in quality, then it looks like the grain problem and palette problem aren’t principled reasons to reject Russellian panpsychism. The question of when information is manifest in the one way or in the other – in particular, whether what matters is specifically spatial and temporal scale – seems to be something that the philosophers can reasonably leave to ongoing, detailed, empirical study.

    The upshot of the foregoing reflections is that Hedda’s convinced me that there’s a prima facie conflict between IIT and Russellian panpsychism, and that her preferred solution is a way out of that conflict. But I think it’s less clear that the rival solutions aren’t equally promising: most of the reasons given for rejecting them seem to either turn on assumptions connecting consciousness with intelligence, which panpsychists need to ditch anyway, or on denying them the benefits of Hedda’s attractive ‘two-birds-one-stone’ approach.

  2. This is an elegant and insightful paper. Russellian panpsychism and IIT, in their current formulations, do seem to conflict for the reasons Mørch gives (although I will raise a question about whether they do conflict). She makes a strong case that the costs of abandoning the Exclusion postulate or the course-graining principle are too high. And her suggested modifications of those theses seem to resolve the conflict in reasonable ways.

    I will do three things. I will raise a question about her argument that Russellian panpsychism and IIT conflict. I will answer an objection she raises against her own proposal for modifying Exclusion. And I will raise a question about the scope of her project.

    Consider these two premises of Mørch’s argument that Russellian panpsychism and IIT, in their current formulations, conflict:

    1. Every major theory of causation entails that the causal structure of the world is determined by the intrinsic properties of things together with the laws of nature.
    2. Russellian panpsychism claims that the intrinsic properties of things are all phenomenal properties. (pp. 14-15).

    Premise 2 is true only if “intrinsic” is understood in an especially strong way. To see this, note that a common example of an intrinsic property is an object’s shape. But physics describes shapes. And according to Russellian panpsychism, physics does not describe intrinsic properties. For this sort of reason, in the literature on Russellian panpsychism philosophers introduce special definitions of intrinsicness or related notions. For example, Derk Pereboom introduces the notion of an absolutely intrinsic property, where “P is an absolutely intrinsic property of X just in case P is an intrinsic property of X, and P is not necessitated by…extrinsic properties of parts of X” (Pereboom 2015, p. 306; that passage occurs in Pereboom’s discussion of Russellian monism, of which Russellian panpsychism is a variety). There are thorny issues here (Stoljar 2015, Alter forthcoming). But for present purposes, what matters is that in premise 2 “intrinsic” must be understood in an special way.

    Thus, a question naturally arises about how “intrinsic” is understood in premise 1. For example, does every major theory of causation entail that absolutely intrinsic properties help determine the causal structure of the world? I am not sure that they do. But if “intrinsic” in premise 1 is not understood in the same, special way that it must be understood in premise 2, then Mørch’s argument commits an equivocation fallacy. To be clear, I do not claim that her argument does commit that (or any other) fallacy. Rather, my claim is that, for her argument to succeed, she would have to show that premise 1 is true if “intrinsic” is understood in the same special way that it must be understood in premise 2.

    Appearance and reality
    Mørch raises an objection against one of her own positive proposals: the relativized Exclusion postulate. The objection is that the relativized postulate implies an appearance/reality gap for phenomenal properties that many Russellian panpsychists reject. She writes,

    Say I have an experience of a tiny patch of phenomenal green, the smallest patch of green that is possible given the grain of my experience. This green patch will be completely uniform green for me, because my experience can’t contain any complexity below its own smallest grain. Now, this uniform green patch will actually be constituted by micro-phenomenal properties at a smaller grain, for example even smaller patches of blue and yellow that are the experiences of the particles in my brain (or some other kinds of particle experiences that we can’t imagine). But then it seems my experience of green is both uniform and partless, and complex, made of blue and yellow (or at least non-green) parts, at the same time.
    Many Russellian panpsychists, and non-reductionists about consciousness in general, are motivated by the principle that there is no appearance/reality-distinction for phenomenal properties (if an experience appears to be of green, then it is of green, phenomenally speaking). If so, it would be contradictory to say that the same phenomenal properties can appear either uniform green or complex yellow/blue (or otherwise non-green) depending on the grain. (p. 12)

    Here we should distinguish two ways in which appearance and reality might come apart (cf. Pereboom 2011, p. 9, fn. 1). One I will call Inaccuracy. Inaccuracy says that X’s real nature might diverge from how X appears in experience. An example might be the shape of a penny when viewed at certain angles. The real nature of that shape is round, but it need not appear round: it might appear to be a thin oval or even a thin rectangle.

    Many non-reductionists about consciousness would argue that Inaccuracy does not apply plausibly to phenomenally conscious experiences (many but not all: see Pereboom 2011, chapters 1-4). At least, they would argue that how a phenomenally conscious experience appears to the experiencing subject cannot differ radically from its real nature in the way that the apparent shape of the penny might differ radically from its real shape. So, the philosophers in question would probably reject the appearance/reality distinction if construed as (radical) Inaccuracy.

    Notice, however, that the example Mørch describes, of a phenomenally green experience being constituted by phenomenally blue and phenomenally yellow micro-experiences, does not clearly involve radical Inaccuracy. Arguably, the experience that appears phenomenally green really is phenomenally green. This is true even though that instantiation of phenomenal greenness is constituted by instantiations of other phenomenal properties. Thus, the Russellian panpsychist’s rejection of (radical) Inaccuracy does not run afoul of the consequence of relativized Exclusion that Mørch’s example illustrates.

    A second way in which appearance and reality might come apart I will call Incompleteness. Incompleteness says that there might be more to X’s real nature than how X appears in experience. An example would be water. In everyday experience, water appears to be clear, tasteless, etc.: it appears to be watery stuff (Chalmers 2010). But there is more to the real nature of water than that, namely, its chemical composition. Water has a backside, so to speak: part of its real nature is not revealed in our experiences of it (at least, outside of the lab). Mørch’s example involving phenomenal greenness also seems to be a case of an experience having a backside.

    Some non-reductionists about consciousness might argue that Incompleteness does not apply plausibly to phenomenally conscious experiences. In particular, emergentist Russellian panpsychists might argue that phenomenally conscious experiences have no backsides. But many Russellian panpsychists would not accept the emergentist’s argument. On the contrary, constitutive Russellian panpsychism a fits well with Incompleteness (so do many other non-reductionist views about consciousness). According to constitutive Russellian panpsychism, macro-experience is constituted by micro-experiences. One might maintain that the phenomenal natures of micro-experiences are entirely revealed in macro-experience. But it seems more natural for constitutive Russellian panpsychists to reject that claim. In any event, constitutive Russellian panpsychism is not motivated by the claim that phenomenally conscious experiences have no backsides.

    My point is this. Insofar the relativized Exclusion postulate entails an appearance/reality distinction for conscious experience, that appearance/reality distinction says not that conscious experiences can be radically inaccurate but rather that they have backsides; and that claim, that experiences have backsides, comports well with constitutive Russellian monism. (I regard this as a friendly criticism: the modification of Exclusion that Mørch devises does not have a problem she suggests it might have.)

    Do Mørch’s arguments generalize?
    Mørch characterizes her project as concerning IIT’s relationship with Russellian panpsychism. But many of her main argumentative moves would seem to apply, mutatis mutandis, equally to the panprotopsychist version of Russellian monism (Chalmers 2010, chapter 6, Pereboom 2011, 2015). Am I wrong about that? If not, then is her project really about IIT’s relationship with Russellian monism rather than with Russellian panpsychism per se?

    (For helpful comments, I thank Sam Coleman and Derk Pereboom.)


    Alter, T. Forthcoming. The structure and dynamics argument against materialism. Nous.
    Chalmers, D. J. 2010. The Character of Consciousness. New York: Oxford University Press.
    Howell, R. J. 2015. The Russellian monist’s problems with mental causation. Philosophical Quarterly 65: 22-39.
    Kind, A. 2015. Pessimism about Russellian monism. In T. Alter and Y. Nagasawa (eds.) Consciousness in the Physical World: Perspectives on Russellian Monism. New York: Oxford University Press, 2015: 401-21.
    Mørch, H. H. Is the integrated information theory of consciousness compatible with Russellian panpsychism?
    Pereboom, D. 2015. Consciousness, Physicalism, and Absolutely Intrinsic Properties. In T. Alter and Y. Nagasawa (eds.) Consciousness in the Physical World: Perspectives on Russellian Monism. New York: Oxford University Press: 300-323.
    Pereboom, D. 2011. Consciousness and the Prospects of Physicalism. New York: Oxford University Press.
    Stoljar, D. 2015. Russellian monism or Nagelian monism? In T. Alter and Y. Nagasawa (eds.) Consciousness in the Physical World: Perspectives on Russellian Monism. New York: Oxford University Press: 324-345.

  3. Response to comments

    Many thanks to Luke Roelofs and Torin Alter for your incredibly insightful and interesting comments! As will be obvious they have given me a lot to think about, and I’m very happy for the chance to have this discussion with you. I also want to thank Nick Byrd, Cameron Buckner and John Schwenkler for organizing this excellent conference. Here are my responses.

    Response to Torin Alter

    1.     Absolute vs. comparative intrinsicality

    In the paper, I claim that:

    (1) all major theories of causation entail that causal structure nomologically supervenes on intrinsic properties,

    (2) Russellian panpsychism entails that all intrinsic properties are phenomenal properties

    Therefore, Russellian panpsychism entails that causal structure nomologically supervenes on phenomenal properties.

    I show that Russellian panpsychism is therefore incompatible with IIT in view of its coarse-graining principle.

    Torin (if I may follow Luke and go by first names) asks whether by “intrinsic” I mean “absolutely intrinsic” or “comparatively intrinsic”. Comparatively intrinsic properties are properties which are necessitated by the extrinsic properties of its parts, thus not “really” intrinsic. This is a very important question. If I mean “comparatively intrinsic”, then premise 2 is indefensible (Russellian panpsychism allows that comparatively intrinsic properties are not phenomenal). If I mean “absolutely intrinsic”, then premise I may be indefensible, because most philosophers allow that causal structure might nomologically supervenes on, e.g, shape, which can be regarded as only comparatively intrinsic. If I mean “absolutely intrinsic” in premise 1, but “comparatively intrinsic” in premise 2, then the argument is invalid by the fallacy of equivocation.

    Here is a brief summary of my response to this comment: I have not construed the coarse-graining problem entirely accurately. After reflecting on this comment, it seems to me the problem is best understood as deriving from commitments specific to Russellian panpsychism, not from general theories of causation. The coarse-graining problem remains the same, but its basis is somewhat different.

    That was the summary, here is my full response:

    To begin by answering Torin’s concrete question: what I meant was “absolutely intrinsic” in both premises. Thus, what premise 2 really should say is:

    Premise 2’: All major theories of causation entail that causal structure nomologically supervenes on *absolutely* intrinsic properties.

    This is intended to capture the intuitive claim that what things do must follow from how they are. Comparatively intrinsic properties are necessitated by extrinsic properties of their parts, hence, reducible to mere doings of the parts. Comparatively intrinsic properties should therefore not really be regarded as part of how things are.

    Is premise 2’ true? I.e., do all major theories of causation aim to capture this intuition? Typically, at least, Humean categorical properties, causal powers, and Armstrong-type categorical universals all seem to be regarded as absolutely intrinsic, not comparatively intrinsic. But is it outright incompatible with all these theories to regard causal structure as grounded in properties that are not absolutely intrinsic?

    One objection is the following. According to ontic structural realism (a la James Ladyman) there are no absolutely intrinsic properties, and causal structure is absolutely fundamental and does not supervene on anything else. But ontic structural realism seems compatible with at least some major theories of causation. Torin suggest that some might hold that causal structure nomologically supervenes on merely comparatively intrinsic shape properties. This view can also be regarded as a form of ontic structural realism, because if shape is comparatively intrinsic, it must be constituted by spatial structure only. Then this view should also be regarded as compatible with at least some major theories of causation, just like ontic structural realism in general.

    If this is correct, it might seem premise 2’ can simply be adjusted as follows:

    Premise 2’’: All major theories of causation entail that *if there are absolutely intrinsic properties,* then causal structure nomologically supervenes on them.

    Or, in more intuitive terms, what things do follows from how they are – unless being is entirely reducible to doing (as per ontic structural realism).

    Premise 2’’ still entails my conclusion (because according to premise 1 and Russellian panpsychism there are absolutely intrinsic properties to satisfy the proviso), but does not entail the somewhat implausible claim that ontic structural realism is incompatible with all major theories of causation.

    However, there seem to be more reasons to doubt premise 2’’. For example, it seems all major theories of causation are compatible with epiphenomenalism about phenomenal properties. If all (or some) of these theories are also compatible with ontic structural realism, it would be coherent to suppose that phenomenal absolutely intrinsic properties are epiphenomenal, while physical causal structure is ungrounded and fundamental as per ontic structural realism.

    The simplest response to this suggestion is probably not to insist that it is really incompatible with all major theories of causation, but rather that it is incompatible with Russellian panpsychism, because Russellian panpsychism denies epiphenomenalism. But if so, it seems the real argument for the conclusion that leads to coarse-graining problem is actually a different and more complicated one:

    1. Russellian panpsychism (RP) entails that phenomenal properties are causally relevant.
    2. If phenomenal properties are causally relevant, then some causal structure nomologically supervenes on phenomenal properties.
    3. RP entails that phenomenal properties are absolutely intrinsic.
    4. Therefore, RP entails that some causal structure nomologically supervenes on absolutely intrinsic properties.
    5. If some causal structure nomologically supervenes on absolutely intrinsic properties, then all causal structure nomologically supervenes on absolutely intrinsic properties.
    6. RP entails that *only* phenomenal properties are absolutely intrinsic.
    7. Therefore, RP entails that all causal structure nomologically supervenes on phenomenal properties.

    Premises 5 and 2 in this argument are not simply derived from Russellian panpsychism and so need some defense.

    One might deny premise 5 by saying that some causal structure (such as the microstructure of fine-grained systems such as silicon or organic neurons) is ungrounded but other causal structure is grounded in phenomenal properties. One way to defend premise 5 against this is just to say that it seems very ad hoc to claim that the world is a mix of pure structure and grounded structure. Furthermore, if causal structure can actually be pure and ungrounded, then phenomenal grounds look like redundant overdeterminers when they are present, which is arguably in conflict with premise 1.

    An objection to premise 2 could be that phenomenal properties can be causally relevant (within Russellian panpsychism) without nomological supervenience. For example, one might think that phenomenal properties realize causal structure without determining it, i.e., are relevant to causal structure in virtue of their (absolute) intrinsicality alone (i.e., as mere “fillers”) but not in virtue of their particular phenomenal character, and that this is sufficient for causal relevance. However, as Robert Howell has convincingly argued, this does not give a very satisfactory solution to the problem of mental causation (“The Russellian Monist’s Problems with Mental Causation”, Philosophical Quarterly, 2015) so it should be rejected by Russellian panpsychists.

    In this way, it seems the coarse-graining problem derives mainly from commitments regarding mental causation specific to Russellian panpsychism, and less from general theories of causation than I initially thought. But the problem still follows, just in a different way.

    2.    Appearance/reality-distinction for phenomenal properties

    In the paper, I propose that IIT might avoid the coarse-graining problem by modifying, but not wholly abandoning, its Exclusion postulate. I object to my own proposal that it seems to entail an appearance/reality-distinction for phenomenal properties which is incompatible with the motivation for Russellian panpsychism.

    Torin makes a friendly suggestion: only some kinds of phenomenal appearance/reality-distinctions are incompatible with the motivation for Russellian panpsychism, those that imply radical inaccuracy (that the phenomenal reality contradicts the appearance). The motivation for Russellian panpsychism seems compatible with appearance/reality-distinctions that merely imply phenomenal backsides (that phenomenal reality involves more than the appearance, where this “more” does not contradict the appearance). He suggests that my proposed modification of the Exclusion postulate might only entail backsides, not radical inaccuracy.

    This is a great suggestion for how to avoid the problem. I think Torin is right that backsides are not necessarily incompatible with the motivation for Russellian panpsychism, and it would be great if my proposal to modify Exclusion could actually work on that basis.

    The question is whether the appearance/reality-distinction that my proposal entails merely commits it to phenomenal backsides only and not radical inaccuracy. My example is an experience that from the coarse-grained point of view is uniform green, but from the fine-grained point of view is complex blue-and-yellow (or another combination of non-green microphenomenal properties). If we describe blue-and-yellow (or other combinations of unknown microphenomenal properties) as “non-green” then the appearance of green contradicts the reality of non-green, which entails radical inaccuracy not a mere backside. But as Torin points out, maybe blue-and-yellow is not accurately described as non-green, because they jointly constitute green.

    My worry is whether blue-and-yellow could constitute uniform green (which I argue is what appears given coarse-graining). Green that is constituted by blue and yellow, or any other non-green qualities, might be green but not uniform green. Proper uniformity requires that any constituents dissolve. The appearance of uniformity equals the appearance of not having constituents. Therefore, the uniformity part (sadly) commits my proposal to radical inaccuracy, not just backsides. Or so it seems to me; I would be happy to be convinced otherwise.

    3.     Russellian panprotopsychism and neutral monism

    In the paper I only discuss whether IIT is compatible is compatible with Russellian panpsychism. Torin raises the question of whether my conclusions apply mutatis mutandis also to other forms of Russellian monism, such as panprotopsychism or neutral monism.

    I restricted my discussion to Russellian panpsychism because IIT is explicitly panpsychist, but it’s worth considering whether it would be a better, worse or equally good idea to combine IIT with panprotopsychism or neutral monism.

    In IIT, microphenomenal and macrophenomenal properties are completely continuous: one can gradually go from one to the other by incrementally increasing Φ. By introducing protophenomenal or neutral properties it seems one would have to say that at some threshold of Φ we suddenly go from protophenomenal/neutral to phenomenal, and any such threshold would seem somewhat arbitrary. So one reason to think IIT is more compatible with panpsychism is that it avoids this arbitrariness.

    However, on the plus-side, one might think panprotophenomenal/neutral properties don’t entail problematic appearance/reality-distinctions in the same way as microphenomenal properties. For example, perhaps the appearance of phenomenal uniformity should be regarded as incompatible with really having phenomenal constituents, but still compatible with really having non-phenomenal (protophenomenal or neutral) constituents.

    If so, one might associate the transition from proto/neutral to phenomenal not with a threshold of Φ, but with the transition from fine-grained to coarse-grained maxima, which does not seem as arbitrary.

    Something like this might be worth pursuing, but personally I’m skeptical to whether panprotopsychism and neutral monism have the same overall philosophical advantages as panpsychism (for other reasons that I won’t go into here), so I’m not too hopeful about it.

    Response to Luke Roelofs

    I’m going to divide my response to Luke into 4 main points.

    1.    The motivation for correlating combination with maximal Φ

    Luke argues that a law correlating consciousness with maximal Φ is inelegant because it has no justification either a posteriori or a priori. From the a posteriori point of view, maximal Φ or its elements don’t correspond to anything in physics. Correlating maximal Φ with consciousness a priori is incompatible with Russellian monism which takes consciousness as fundamental, and thereby not a priori analyzable into anything else.

    I don’t see it as a problem that maximal Φ or any of its elements don’t correspond to anything in physics. The only way to get a correlate of combination that is motivated by physics seems to be if we discovered some quantum coherence at the brain level, or if strong emergentism (a la C.D. Broad) turned out to be true, i.e., if microphysical causal closure turned out to be false. IIT seems to give a kind of correlate of combination that’s as good as you can get without coming into conflict with microphysical causal closure or positing radical new quantum hypotheses.

    IIT posits a single, well-defined property that both particles, human brains (or NCCs) and other things that we might think have combined consciousness unambiguously have in common. That is to say, it’s not disjunctive, as opposed to other views one might take, for example, the Van Inwagen-inspired view that unified consciousness is found in particles and organisms only. So in that respect it’s quite elegant.

    It’s also a posteriori motivated insofar as it aligns with (clinical, relatively theory-independent) judgments about when and where unified consciousness appears (wakefulness, dreaming), disappears (coma, deep sleep, anesthesia) or never occurs at all (i.e., why the cerebrum but never the cerebellum). I’m not sure what other kinds of a posteriori motivation would be possible. That is not to say that this a posteriori motivation could not be better – Φ is notoriously hard to measure so it’s far from strictly confirmed that it accounts for the coming and going of unified consciousness as well as I have indicated, but it seems to have made a good start.

    As noted in the paper, I set Tononi’s a priori motivation for IIT mostly aside and focus on Φ simply as a correlate of combination. IIT’s a priori motivation is somewhat difficult to get clear on, but I still think it is quite clear that it would not necessarily be incompatible with Russellian panpsychism. Luke implies that a priori correlations between consciousness and other properties are necessarily reductionistic. However, consciousness can also be correlated with other properties on the basis of structural similarity or isomorphism, which does not imply reduction. This is what IIT seems to do. It identifies some structural features that all experiences seem to share from the phenomenological point of view, and then takes it that consciousness should be correlated with physical systems that instantiate the same structure causally (this structural property is Φ). But why think consciousness is correlated with a structurally similar physical system, if not on the basis of a priori reductive analysis? As I said, this is somewhat difficult to get clear on, but here is one rough interpretation: the best explanation of why consciousness is correlated with physical systems such as the brain at all is that the phenomenological and physical points of view constitute two aspects of the same structure (the intrinsic and the extrinsic). If so, individual conscious experiences should be correlated with physical states which instantiate the same structure physically that the experiences do phenomenologically. This correlates consciousness with Φ via abduction, not reductive a priori analysis.

    2.    Why not universalism?

    In the paper, I claim that one of the reasons why we should combine IIT with Russellian panpsychism is that this gives us a correlate of combination that does not lead to universalism, the view that any thinkable object (any collection of particles or perhaps points/areas) has unified consciousness. I also argue that IIT should not abandon the Exclusion postulate because this would imply universalism or at least get it quite close to it.

    Luke claims that universalism might be counterintuitive, but there is no good reason to trust this intuition, especially when panpsychism already goes against widespread intuitions about what kinds of things are conscious. He suggests that bias against universalism in based on the intuition that consciousness necessarily connected with intelligent behavior.

    It should be noted that IIT explicitly disassociates consciousness from behavior, intelligent or otherwise. In IIT, consciousness only depends on connections between the system’s parts, not at all on connections to the environment. Thus, systems that are disconnected from their environment can be just as conscious as systems that have advanced inputs and outputs, as shown by dreams and hallucinations.

    IIT is rather based on the intuition that consciousness must have maximal internal unity and coherence, of a kind that non-integrated aggregates that are conscious according to universalism don’t have. This intuition seems to be shared by many philosophers including panpsychists. I’m not sure how to best defend this intuition, but here is an attempt.

    One worry with universalism is that it’s pretty hard to imagine what it could be like to be an aggregate such as, say, the combination my toe and a piece of my shoe, an arbitrary 30% area of the brain area that supports my consciousness, or the set of two people fighting. One might retort that it’s also pretty hard to imagine what it is like to be a fundamental particle. But it’s a different challenge to imagine what it is like to be a simple, but unified thing, than to imagine what it would be like to be a wildly disunified thing. Phenomenological simplicity may be hard to imagine mainly simply because our power of imagination is limited, whereas phenomenological disunity/incoherence seems hard to imagine because it’s hard to even make sense of.

    The experience of a system such as <my toe and a piece of my shoe> or <an arbitrary 30% area of the brain area that supports my consciousness>, and <the set of two people fighting> would have to be a very incoherent and meaningless experience, perhaps even paradoxical. In the case of <the set of two people fighting> it would involve being conscious of contradictory thoughts (person 1 is thinking “person 2 is wrong”, person 2 is thinking “person 2 is not wrong”; the aggregate is having both thoughts). In the case of <30% of a brain area> it would seem to involve something like thinking 30% of a thought, or having 30% of a feeling, which does not make a lot of sense either. There is nothing similarly borderline paradoxical about the idea of a very simple but still unified experience.

    A further worry is that if universalism is true, the number incoherent, meaningless or absurd experiences would be vastly higher than the number of meaningful and coherent experiences, because the number of arbitrary aggregates is vastly higher than the number of unified (by IIT’s criterion or otherwise) systems. This seems like very tragic situation and I would feel very fortunate that I’m having one of the comparatively few coherent and meaningful experiences. Perhaps one can’t regard a theory as less likely to be true merely because it has tragic consequences, but at least it gives motivation to see if it’s possible to make sense of a less tragic alternative.

    3.    Why not correlate low Φ with lack of memory/reportability

    One way of avoiding the coarse-graining problem is to abandon IIT’s Exclusion postulate. I argue that not only is this a bad idea because it leads to universalism, but because IIT with Exclusion enables a better explanation of why macro-consciousness seems to disappear in states like deep sleep and anesthesia than IIT without Exclusion.

    Human macroconsciousness seems to disappear long before the Φ of the brain area associated with it reaches zero. Given Exclusion, IIT can explain this as follows: when we go into deep sleep/anesthesia, the Φ of our NCC goes lower that the Φ of parts of the NCC. Without Exclusion, IIT would have to say that macroconsciousness does not disappear, it just becomes dimmer, simpler, or less intense, and therefore we don’t remember it (or can’t report remembering it, but from introspection I can at least rule that out for myself). I claim that the latter explanation is ad hoc, because there is no reason to think low Φ (dim/simple experience) is necessarily correlated with lack of memory or reportability.

    Luke questions whether this explanation is really that ad hoc. The correlation between memory/reportability with high Φ is supported by the fact that we already know that simple, low Φ entities like fundamental particles can’t report and it’s fair to assume they don’t have memory. In my response, I will focus on memory only (since from my own case I know that I don’t have memories of deep sleep that I can’t report), and set anesthesia aside (to keep it simple).

    I think Luke is correct that a correlation between memory and high Φ is not as ad hoc as I implied. It’s fair to assume that memory is connected with complexity, and low Φ states have less complexity. However, I do not find it plausible that less complex states are less likely to be remembered merely in virtue of being less complex, at least not on the basis of what I take to be the most basic, schematic characterization of what memory is.

    The most basic, schematic characterization of memory is that memory is the capacity of a present experience to represent, and thereby in some way contain a (full or partial) copy of, a previous experience. In order to contain a copy a previous experience, the present experience must be at least as complex as the previous experience (or the part of it that is remembered). This point would explain why we can’t (fully) remember our complex waking experiences while we are dreamlessly sleeping and having a less complex (low Φ) experience. But it would not explain why we can’t remember our less complex deep sleep experiences when we are back to complex wakeful states.

    In order to contain a copy of a previous state, the present and previous state must jointly support some sort of copy mechanism. One might think low Φ sleep states are so simple that they can no longer cause copies of themselves to occur in a later experience. But it does not seem obvious that the copy mechanism could not depend mainly on the complexity of the later state. Hence, an explanation of why we don’t remember deep sleep macroconscious experiences that does not appeal to Exclusion would need to bring in more details about how memory actually works.

    The explanation in terms of Exclusion is much more straightforward and requires no elaboration: the reason we don’t remember deep sleep macroconscious experiences is because there are no such experiences.

    4.    Recombining my proposals

    I’m happy to hear that Luke likes my proposal for solving the palette problem and the grain problem. The palette problem says that macroconsciousness has too many qualities, the grain problem says that macroconsciousness has too little structure, so I suggest that the missing structure is somehow encoded in the surplus qualities.

    Luke suggests that this solution is compatible with my proposal to modify Exclusion, which seems to me correct. The reason I proposed it only for the other proposal to modify coarse-graining is that only for this proposal is the palette/grain problem solution essential to making IIT compatible with Russellian panpsychism, which was my primary aim. But the aim of solving the palette problem and grain problem is of broader interest than this, so it should be worth incorporating into the other proposal and also worth pursuing independently of IIT.

    However, it seems to me that it might not be possible to pursue it without some coarse-graining principle at least similar to the one that’s part of IIT. Luke also suggests that the “two birds, one stone”-solution is compatible with abandoning coarse-graining completely. But if there are no coarse-grained levels, it seems to me there are no points of view from which a complex set of microphenomenal qualities from a small palette can be transformed into or appear as a uniform quality from an expanded palette. One might still define what constitutes a coarse-grained level in a different way than IIT does, that is, one can still abandon IIT’s coarse-graining principle if it can be replaced by another kind of coarse-graining principle.


    Thanks again to Luke and Torin for your sharp and helpful comments! I hope I have understood all your points correctly and that I have not neglected to respond to anything – otherwise let me know. I’m looking forward to more discussion in the rest of this session.

    1. Hedda’s reply has forced me to think harder about several of the critical points I made, and clarified several of the things in her incredibly stimulating paper that I took issue with. I hope she’ll forgive me for adding a ‘response to response to comments’!

      The Motivations for IIT:
      I suggested that neither regarding IIT as an a priori conceptual necessity, nor positing it as a posteriori law of nature, was a very good theoretical fit with the kind of naturalistic anti-physicalism that motivates a lot of Russellian panpsychists.
      Hedda suggests, on the first score, that IIT might be a priori not as a reduction but as a necessary correlate based on structural similarities. I’ll concede that this is a way around the scruples I registered, though as Hedda notes the a priori case for IIT is not altogether clear.
      On the second score, Hedda points out that IIT is at least non-disjunctive, with some empirical support, and may be the best we’re going to get if we don’t find special sorts of quantum entanglement in the brain.
      Here I’ll just note that whether it’s ‘as good as we can get’ depends on whether we’re committed to combination happening only under specific brain-like circumstances. Someone willing to be universalist, or close-to-universalist, has plenty of perfectly natural physical relations that stand out as potential correlates of consciousness, like exchange of energy or sharing a spacetime manifold – or even quantum entanglement. But this really shifts the discussion onto the next point…
      Why not universalism?
      Hedda’s right to say that universalism has some implications that are hard to think through, but I don’t think they’re as paradoxical or tragic as she makes out. Indeed, I think they’re implications that are also posed by the forms of disunity and imperfection that human life itself involves.

      The question ‘what is it like to think two conflicting things at once?’ has been discussed by philosophers in the context of the split-brain phenomenon, and what emerges is that there’s nothing paradoxical about a single subject having thoughts with contradictory contents, as long as i) they’re not both having and not having the same thought, and ii) there’s no mechanism that can focus attention onto both thoughts at once. After all, it must be possible to have contradictory beliefs, at least, because people often do – especially when they don’t or can’t focus attention on both beliefs together.

      Similarly, what is it to have 30% of a thought? It’s not easy to say, but there are a lot of ways that thoughts might be divisible, might arise from the concatenation or super-imposition of multiple processes. 30% of a visual image might be a smaller visual image, or a ‘layer’ like just the motion-components, or just the colours. It might be something less familiar – no doubt it would depend on which particular 30% of the brain we’re talking about.
      But I don’t think there’s anything unattractive about the general thought that complex mental states can have simpler mental states as component parts. Maybe parts of thoughts display something akin to ‘semantic deference’, with content that is filled out by the other brain areas just like the content of my thoughts is partly filled out by experts in my linguistic community.

      I should emphasise that I say all this not to deny that Hedda’s remarks identify real, challenging, theoretical difficulties. But I see them as fertile directions for philosophical investigation, rather than as reasons to reject the possibilities in question.

      (As to the tragic implications – personally I’d rather have an incoherent, meaningless, or absurd experience than one as dull as that of an electron! Absurdity isn’t painful, after all (and when there are cognitive mechanisms that associate absurdity with pain, discomfort, or tension, well then you’re halfway towards cognitive mechanisms that can resolve the absurdity). But whether it’s more tragic that ‘most beings are super-dull particles and only a few are humans’ or that ‘most beings are mere aggregates and only a few are humans’, wouldn’t it be even more tragic that ‘most beings aren’t even conscious at all’ – a result which most people swallow without blinking? I’m very unsure how much sense it makes to deal in these kinds of statistical reflections.)

      Why not correlate low phi with lack of memory?
      I suggested that there’s no need to link low phi with unconsciousness, as the exclusion postulate implies, in order to explain why people pass out when in (estimated) low-phi states. We can instead just say that they have a dim, unreportable, unmemorable consciousness. Hedda asks why it should be that dimmer and simpler conscious states don’t leave memory traces, pointing out that if anything it should be easier to store a copy or record of a simpler state than of a more complex one.

      But I think IIT itself provides an answer. When phi is low, the state of each brain area doesn’t carry much information about the states of other brain areas (by definition). But surely whatever mechanisms lay down memory traces, they do so on the basis of receiving information about what’s going on the rest of the brain (again, almost by definition). If the hippocampus (or wherever) is ‘in the dark’ about the rest of the cortex, surely the natural thing to expect it to do is to stop laying down new memories – after all, if it does lay down memories, they’ll have little to do with whatever else is going on in the brain, and so will just be senseless fantasies.

      Abandoning coarse-graining, but keeping blending
      I suggested that the two-birds-one-stone approach that Hedda suggests to the palette and grain problems is a good one, which need not be combined with the specific version of IIT that she suggests (indeed, my work develops essentially that very approach). Hedda agrees, so I won’t argue!

      I will, though, add a thought that perhaps connects Hedda’s comments to me about needing some sort of coarse-graining principle, and her comments to Torin about phenomenal backsides. In the latter comments she says:
      “Green that is constituted by blue and yellow, or any other non-green qualities, might be green but not uniform green. Proper uniformity requires that any constituents dissolve. The appearance of uniformity equals the appearance of not having constituents.”

      I have to say, I just don’t feel that the uniformity of my green experiences is a positive part of their phenomenal character. I can’t discern differently-coloured elements within them (well, usually I can, but the argument just ramifies down to the colours of those smaller elements), but that’s the lack of an appearance, not an appearance in its own right. I’m wondering what Hedda would say to an interlocutor who just denied that they experienced ‘uniform green’ as such.

      Once again, thanks to Hedda and to the organisers for this opportunity to discuss what seem to me some of the most interesting questions around!

  4. Hi Luke, thanks for taking the time to respond to my response! Glad that you find these questions as interesting as I do.

    I agree the case against universalism is far from clear cut. A few points (that I don’t take to be definitive). You give the example of split brain cases to illustrate how there can be contradicting thoughts in one subject. In my view split brain bases seem to involve two subjects in one brain (or perhaps one subject switching back and forth), not one disunified subject. I suspect it’s hard to settle this question independently of the question of we are discussing. If you think it’s paradoxical that one subject has two contradictory thoughts (i.e. two thoughts with precisely opposite contents, which is weaker than having and not having the same thought), then one would be inclined to think split brain cases are also cases of split subjects. If one thinks two contradictory thoughts is fine (only having and not having the same thought is impossible), then one would be inclined to think split brain cases need not involve split subjects. So maybe there is not much help in appealing to this.

    Maybe electron experiences are dull (my intuition is not so clear but I will leave that aside…), but we don’t get fewer of those experiences by adding incoherent universalist forms of experience anyway (a good way of getting fewer of both is to accept something like IIT’s Exclusion principle)… But I agree it’s probably not the most illuminating strategy to argue in this way about which theory of combination gets us “the best of all possible worlds”! But perhaps identifying what we find ethically bad or tragic about the results of certain theories combination can sometimes give a clue to what is bad about them in a more theoretical sense, therefore it can be worthwhile as an experiment.

    Here is another experimental argument against universalism:

    It is a priori true that the co-consciousness relation is the most unifying relation between phenomenal properties that exists (or that the unity of consciousness is the strongest kind of phenomenal unity).
    Therefore, there cannot be minds whose phenomenal parts are more unified than the minds they are part of.
    Aggregates (such as my shoe and my toe) have parts that are more unified (by any measure, not just IIT’s) than the whole aggregate from the physical point of view.
    Physical structure should match phenomenological structure.
    Therefore, aggregates can’t have unified minds.

    I would be curious to know which parts of this argument you (or anybody else reading this!) would disagree with (one or more premises, or overall validity…) and why.

    I also wanted ask more about the point you make about phenomenal grain. You claim that:

    I have to say, I just don’t feel that the uniformity of my green experiences is a positive part of their phenomenal character.

    My question is: If you think there is no positive appearance of uniformity, how does this affect the grain problem? I always thought the grain problem derives from positive appearance of uniformity. But perhaps it could be thought to derive merely from lack of a positive appearance of complexity (if these are really distinct options, I’m not entirely sure I can conceive of one without the other). But if so, would it mean that the grain problem is less serious that it is generally thought to be?

    As for low &Phi and memory, you claim that:

    When phi is low, the state of each brain area doesn’t carry much information about the states of other brain areas (by definition).

    That’s doesn’t seem to me entirely correct, because &Phi measures the information a system carries about itself, not about other systems. So the low &Phi states might still be well-connected to other systems (perhaps they shouldn’t be connected in ways that would make the low &Phi system and memory-serving system it is connected to get high &Phi together, but this seems avoidable. &Phi only increases if there is mutual influence, so the low &Phi system can influence the memory-serving system as long as it isn’t influenced in return with no increase of &Phi). Maybe one can still get the sort of implication Luke suggests, but I find it very hard to evaluate. In that respect I think my point stands that an account of no memory of sleep that does not appeal to Exclusion is not straightforward (which is not at all to say that it can be ruled out, it will just have to appeal to non-obvious empirical details).

    Thanks again, Luke, I really appreciate this discussion!

    1. Thanks Hedda, I figured you might want to say that about split-brain patients – that they’re not one subject with disunified consciousness but two subjects. Without getting into how well that squares with the partial unity they do display, I’ll just say that it seems to me that both sorts of account are conceivably correct, which makes me less inclined to think that disunified consciousness is strictly inconceivable. But as you say, I suspect we’re just going to find the same disagreement in a new guise here.

      (I suspect there may be more than one good concept deserving the label ‘subject’ around here. There may be a sense of ‘subject’ in which a high degree of unity and coherence is a necessary condition on being a subject, and another sense in which a subject is something more like a mere locus for consciousness to go on at, regardless of the coherence or otherwise of its contents. Ideally a panpsychist theory of combination would be able to say something about both.)

      You offer an argument that begins:

      “It is a priori true that the co-consciousness relation is the most unifying relation between phenomenal properties that exists (or that the unity of consciousness is the strongest kind of phenomenal unity).
      Therefore, there cannot be minds whose phenomenal parts are more unified than the minds they are part of.”

      I’m afraid I don’t know what the first sentence means. When I see the word ‘unifying’ I take it as a stand-in for some more specific sort of relation, or an umbrella term covering several. So I just can’t see what it would mean for one relation among properties to be ‘the most unifying’.

      Insofar as I can understand the first sentence, I think it has easy counterexamples. All of the experiences I can currently report are co-conscious, but some are much more unified with one another than others are – for instance, some of my visual experiences are bound so that I see one object with many qualities. Some of my conscious thoughts are relevant to some of my current actions, but irrelevant to others. Some of my bodily sensations forms characteristic gestalts, like when my various fingers detect different edges of a single shape and recognise the shape. When I focus my attention on two experiences at once to compare them, they are in a sense ‘more unified’ than they were a moment before.

      So I’m not really seeing where you’re coming from. Could you elaborate?

      Regarding the grain problem, yes I do think that if there is no positive impression of uniformity (what I called ‘phenomenologically simple character’ in my 2014 paper on the topic) that does significantly contribute to the project of resolving the grain problem. I mean, part of the problem is that it’s really unclear how to decide whether we’re positively presented with uniformity or just not presented with distinguishable elements, so insofar as that’s part of the problem the problem remains.

      Finally, what about memory. You’re right that a general lowering of information-integration is compatible with some particular information links remaining strong. But although the general reduction in information-integration doesn’t guarantee the informational impoverishment of a particular system or connection, it does seem to me to still be a ‘straightforward’ explanation. By analogy, turning off the lights clearly doesn’t guarantee that light won’t reach my retina, let alone that I’ll stop having visual sensations. But given what the visual system is set up to do, it looks like a good explanation to me. I think to get clearer on this we might need to look more closely at what the relevant data actually are (given that nobody has ever actually calculated phi for a real system, you know…)

  5. Hedda,

    Thanks for the great paper, interesting stuff as always! Really good comments from Luke and Torin too (I’ll follow suit and use first names).

    I like the argument against universalism, so I’ll comment on that a little:

    1) It is a priori true that the co-consciousness relation is the most unifying relation between phenomenal properties that exists (or that the unity of consciousness is the strongest kind of phenomenal unity).
    2) Therefore, there cannot be minds whose phenomenal parts are more unified than the minds they are part of.
    3) Aggregates (such as my shoe and my toe) have parts that are more unified (by any measure, not just IIT’s) than the whole aggregate from the physical point of view.
    4) Physical structure should match phenomenological structure.
    5) Therefore, aggregates can’t have unified minds.

    So this argument works because aggregates have parts which are more unified than the whole and minds cannot have parts more unified than the whole itself, hence, because of match between the physical and phenomenal, we must say that aggregates can’t be unified minds.

    Firstly, if co-consciousness is a non-transitive relation, then I think (2) may be false, or at least questionable. My experiences, for instance, may all be directly co-conscious, but I may be a proper part of a larger mind which has mostly indirectly co-conscious experiences. This may qualify as an instance of a mind-part being ‘more unified’ than a mind-whole. Maybe this idea could be illustrated by a split brain example again: one part, i.e. a hemisphere, is more unified than the whole, i.e. two partially overlapping hemispheres.

    Secondly, is (4) thrown into some doubt in light of your ‘two-birds-one-stone’ style response i.e. encoding phenomenal quality in physical structure. Could physical structure not match qualitative variation now? Maybe if we have an aggregate with parts that fall below the relevant grain size for measuring PHI?

    Thirdly, on (2) again, could your formulation of this be falsified by a mind which had two simple minds as proper parts? The proper parts of the simple minds are not more unified than the mind of which they are a part precisely because they do not have proper parts. Reformulating it to something like ‘there cannot be minds which are more unified than the minds they are part of’ would allow you to capture the case of a mind with simples as parts.

    This may or may not be something you want to do: if the panpsychist thinks that (2) is true, the world is made of mereological simples, and co-consciousness is the unity that characterises these simples, then it looks like we will be coming close to never having mental combination. Moreover, if we think (4) is true, and phenomenal and physical structure should match, we will be coming close to never getting physical combination, and, hence, your argument not only shows the falsity of universalism but affirms the truth of nihilism.

    Finally, as Luke says there may be some confusion in (1), but I think I understand what you mean, Hedda: ‘co-consciousness is the most unifying relation between experiences’, more so than causal relations for instance. On Luke’s exmaples: paying attention to two of my experiences does not seem to make them more co-conscious, they just seem to be the focus of my attention. If I stare at my keyboard at the G and H keys, it seems that the key experiences closer to the periphery of my attention like DELETE or NUM LOCK are just as co-conscious with my experience of the G and H. Likewise, that certain visual experiences are bound as objects, e.g. a chair, doesn’t seem to make them more co-conscious than two parts of experiences of distinct bound objects, e.g. the leg of one chair and the arm of the chair next to it. That being said, I do share the suspicion that when using ‘unity’ we may be talking about quite a few different things.

    I hope you find the comments helpful.


    1. Thanks Greg, but I’m not quite seeing how your suggestion about that first premise works. What you seem to say is that co-consciousness doesn’t admit of degrees – establishing other relationships between experiences doesn’t make them ‘more co-conscious’. I’m inclined to agree (I rather like Tim Bayne’s construal of co-consciousness as ‘the composite state formed by these two experiences is itself a larger phenomenal state’, and I don’t think ‘being phenomenal’ comes in degrees).

      But that seems to me to have nothing to do with a comparison between different relations according to which ones are ‘more unifying’. On what single measure does co-consciousness score higher than, say, causal interaction? The point you make, and which I agree with, seems to suggest that co-consciousness is sharply distinct from those other relations, so what does it even mean to rank and compare them?

      (By analogy, and hoping this doesn’t muddy the waters even further, the premise as you interpret it says something like ‘being equidistant is a more unifying relation than being the same colour’, and I said I didn’t know what that meant. You’ve pointed out that things can be of the same or different colours, without that making them more or less equidistant, and indeed being equidistant may not come in degrees at all. But that doesn’t help me at all to know what it means to compare two distinct relations according to their ‘unifyingness’.)

  6. Great paper and great comments! Really enjoyed this, although it hurt my head a bit…

    I’m very sympathetic to the things Luke says about universalism. I’ve never really understood why most panpsychists dismiss it as counter to common sense.

    I want to say something about the issue Torin raises about phenomenal properties potentially having backsides. My response to this in my book (sorry for the plug, but it’s relevant) to this kind of strategy (which I call ‘phenomenal translucency’ and discussed in section, also relevant is discussion of ‘partial revelation’ in 5.5…full manuscript on my website…) is that I want to hear a detailed account of phenomenal concepts that entails it. Exactly which aspects of the conscious state are revealed and which hidden? In each case how is reference fixed, and how does this fit in with the reference fixing of the whole phenomenal concept? Robert Schroer has a detailed physicalist account of phenomenal concepts that entails phenomenal translucency. But, although Russellian monists often gesture in that direction, I’ve never seen these details filled in. And until they are, we can’t really evaluate the proposal.

    Having said this, I don’t agree with Hedda’s argument that Torin is responding to. It’s perfectly coherent to suppose that I grasp the full nature of my green experience without knowing anything its micro-level constituents, so long as my experience is not identical with its micro-level constituents. Compare: I can grasp the nature of the property of being a heart, without having any idea about the underlying physical nature that realises that property. I don’t think phenomenal properties are functional properties, but why shouldn’t they also be multiply realisable? (I make this point in response to Luke in 8.1.1 of me book…sorry for the plug again!)

  7. Thanks, Luke, Greg and Philip!

    So it seems some people (like Greg and I) find it intuitive that subjects must be more unified than their experiential parts/aspects, and others (like Luke and Philip) don’t. I’m not sure what more to say in defense of my intuition at the moment. I will think about it more in view of this very helpful discussion.

    To Greg:
    You are right that premise 4 should be weakened if it is to be compatible with my “two birds, one stone” solution to the grain and palette-problem. It should not require perfect match between physical and phenomenal structure, but only that they correspond in some weaker sense. I have to think about this more. Thanks for pointing this out!

    As for premise 2, it does seem it might rule out minds having other minds as proper parts. If so, you can still get mental combination with the fusion view, but constitutive panpsychism in general seems ruled out, which is perhaps not a good result because the argument was only supposed to target universalism, not constitutive panpsychism in general. Perhaps a constitutive panpsychist can say could say that there can be parts of minds that are also minds as long as these parts are not more unified than (just equally unified as) the whole. Perhaps they could also say that even if the unity of consciousness is stronger than any other kind of unity, there are degrees of such unity. So the lesser minds can be less unified than the greater mind, but stronger than any other unities.

    To Luke:
    I’ll read up on your work that you mentioned, thanks for the pointer! As noted, I admit I don’t have much more to say about the first premise in the argument against universalism at the moment, will think about it more. I still don’t quite understand the explanation you suggest of lack of memory, but you are probably right that there are more resources to deal with this in IIT than Exclusion. I’ll think more about this too.

    To Philip:
    Your point that we might grasp the full nature of an experience without grasping the nature of its constituents is clearly very relevant. I don’t take myself to have argued against this – I just think it’s a controversial idea (it’s not obviously false but not obviously true either, maybe for hearts but not for experiences) and a full defense of my proposal to modify Exclusion would probably need to include a defense of something like this point (in order to accommodate backsides as Torin suggested).

    1. Like Hedda, I think it’s one really useful upshot of this discussion to bring out the intuitive divide over universalism and unity. The argument against universalism that Hedda offers and Greg endorses (which I have to admit I still don’t know how best to interpret) looks to me to have something very close to the Exclusion Postulate itself as a premise, which suggests that there may be a dispute to have over Exclusion that doesn’t focus on its implications but just on its intrinsic intuitiveness.

      (The difference that should be noted is that Exclusion is explicitly about systems that are conscious, i.e. about subjects, while Hedda’s premise is about co-consciousness, which I at least had understand to be a relation among experiences, and only indirectly between subjects.)

      I’m wondering how far this conflict of intuitions parallels people’s intuitions on the following principle:

      ‘Two experiences belonging to distinct subjects cannot be co-conscious.’

      This says nothing about degrees of unity, but I suspect people sympathetic to Hedda’s premise will also be sympathetic to this principle. If people think I’m right that there’s a connection, it might be relevant to point up a paper I recently put out explicitly arguing against the above principle.

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