Panpsychism and Mental Monism: Comparison and Evaluation

Panpsychism and Mental Monism: Comparison and Evaluation

Peter Lloyd

In the contemporary debate on the Cartesian mind-body problem, the theories of panpsychism and mental monism are receiving growing attention as candidate accounts of the conscious mind. Panpsychism asserts that consciousness pervades a spatially extended physical universe, while mental monism asserts that consciousness exists in a purely mental domain, and denies the reality of physical substance and space. In this paper, I compare the two theories and evaluate whether each is true. They seem fundamentally contradictory, but I propose that they are closer than they seem. I argue that their apparent difference rests on a category-mistake (in Ryle’s term), a misplaced reification of the physical. My claim is that physics is topic neutral (in Foster’s use of the term) and that consequently situating consciousness in a purely notional physical universe adds nothing to our concept of reality beyond what mental monism gives us. I argue that: First, when we see physics correctly through the lens of topic neutrality, the physical part of panpsychism disappears and the theory reduces to mental monism. Second, that mental monism is true as a general thesis. That is, reality ultimately consists of nothing but conscious minds. Third, that panpsychism is false and that a Berkeleyan flavor of mental monism resolves the Cartesian mind-body problem, which in recent years has received attention in the form of Chalmers’ Hard Problem. Besides providing a resolution of this philosophical problem, mental monism also potentially offers a platform on which to build a naturalistic account of psi phenomena.

[Laird]

Am in the middle of reading this, Sci. Very interesting so far. I decided to dig in to it given that in my review of Bernardo Kastrup's Why Materialism is Baloney, I'd suggested that at an abstract level, idealism, (cosmo)panpsychism, and some form of dualism could all be accommodated without conflict. It looks like this essay might shed further light on that suggestion, potentially throwing a spanner or two into its works.

Incidentally, I couldn't find it at the link you supplied - it seems to have changed to https://www.researchgate.net/publication...Evaluation

[Laird]

I've (finally) finished reading this paper - here's an extended summary for those who don't want to, or don't have time to, read all 48 pages. In a follow-up post I my respond to the paper as this post summarises it.

First, a couple of notes on terminology. The author uses "mental monism" as a synonym for "idealism" (as well as for "subjective idealism" and "mentalism"). This seems consistent with that which I understand to be Bernardo Kastrup's position: that the idealism for which he advocates is "nondualism" by another name; "(mental) monism" and "nondualism" being essentially synonyms. He also uses "metamind" for that which Berkeley referred to as "God" and Śankara referred to as "Brahman" (to which I will add that also for this, Bernardo Kastrup has used "mind-at-large").

He undertakes some analysis to define and compare panpsychism and idealism / mental monism. First, he asserts this comparison between (micro-)panpsychism and micro-idealism:

• (Pφ) (Micro-)panpsychism: The basic units of reality are fundamental physical entities, and some or all of these possess ‘elemental’ minds (not composed of smaller
  minds).
  
• (Pψ) Micro-idealism: The basic units of reality are elemental minds, and some of these possess the extrinsic relations of fundamental physical entities.
  

However, on his view that "mental locality is impossible" because there is no substantive space described by physics over and above the extrinsic relations that comprise it (physics), he finds that "Micro-idealism, therefore, is conceptually distinct from panpsychism, but the difference is superficial, not substantial."

He then arrives at (Pυ) "neutral panpsychism" in which "There is a one-to-one mapping between fundamental physical entities and elemental minds".

Pointing out that "Panpsychism’s literature lacks a principled account of ‘fundamental physical entities’", and in view of the difficulty of defining them, he defines "‘generalized neutral panpsychism’ (GPυ)" as that in which "There is a one-to-one mapping between some physical entities, not necessarily fundamental, and elemental minds."

He goes on to distinguish two versions of mental monism: "‘Monolithic mental monism’ says that the metamind is not separable into constituents corresponding to bodies; and an ‘object-oriented mental monism’ maintains the Berkeleyan thesis that the metamind is separable into encapsulated archetypes corresponding to observed physical entities. The latter is a more parsimonious model and in what follows I shall consider only object-oriented mental monism."

He finally arrives at the following normalised summary and comparison of panpsychism and mental monism, in which the last two list items are shared between microphysical panpsychism, generalised panpsychism, and object-oriented mental monism:

• There is a one-to-one mapping of:
  
  • (in microphysical panpsychism) fundamental physical entities and elemental minds;
    
  • (in generalized panpsychism) some physical entities and elemental minds;
    
  • (in object-oriented mental monism) physical entities and object-minds.
    
• The physical properties (of each physical entity) are constituted by extrinsic relations between those entities.
  
• The intrinsic properties (of each mind) are phenomenal mental qualities.
  

Of this, he writes: "We see that: microphysical panpsychism is a special case of generalized panpsychism, which is a special case of object-oriented mental monism, which is a special case of general mental monism. (We also see that micro-panpsychism and micro-idealism are equivalent.)"

It is important to note that (as I understand it), in the terms above, ordinary (human) personal minds correspond roughly to "object-minds", whereas they (ordinary human personal minds) are constituted by aggregates of "elemental minds". Thus, the key distinction that the author makes between panpsychism and idealism / mental monism is not based in the ontological status of mind and matter and the relationship between the two, but in the way that mind is individuated and/or aggregated in its relationship with matter. This is made more explicit later in the paper where the author writes that "the core intuition—shared by panpsychists and object-oriented mental monists alike—[is] that we should expect the structure of the mental world to mirror the physical world, but panpsychists and mental monists require it to be at the micro and macro levels respectively".

Having established these definitions, he mounts an argument whose conclusion is that "reality is a non-panpsychist form of mental monism" (it is thus an argument for mental-physical mirroring at the macro rather than micro level). His argument has two steps: first, he argues that mental monism is true; second, he argues that panpsychism is false.

He argues for the truth of mental monism using the anti-physicalist argument that he calls his "Berkeleyan semantic argument", which he summarises thus:

"All physical terms are defined analytically in terms of undefined fundamentals, whereas all mental terms are rooted in private ostensive definition. Therefore physical terms and mental terms form disjoint sets, and so physical propositions and mental propositions are disjoint, hence no mental fact can be grounded in physical facts. This delivers the first limb of mental monism. The second limb stems from the fact that we have direct experience of mental content but not of mind-independent physical systems. This enables us to establish reference to mental entities but prevents us from making reference to those physical things. Any assertion that a mind-independent world exists is therefore an incoherent attempt to refer to what is unreferenceable, or what Berkeley termed an “unknown somewhat” (1710, §80; 1713, p 482). Therefore, the whole of physical discourse has the character of a text that refers to nothing outside itself, that is to say, it is a fiction, albeit a convenient one."

He goes on to unpack this argument at some length, and if you find the above summary difficult to follow, then I recommend reading that unpacking in the paper itself, between (inclusively) pages 21 and 29. It seems helpful though to share his conclusion, which reiterates the above summary in different words:

"Bringing these two limbs of argument together, we find: first, the domain of consciousness is not reducible to physics; second, the physical domain to which we ordinarily refer is a construct grounded in our phenomenal content; third, any attempt to refer to a mind-independent physical world is incoherent. We must conclude that reality comprises only conscious minds, and that what we take to be the physical world is a construct within this mental world."

In arguing for the falsity of panpsychism, he first clarifies that he doesn't "see anything philosophically problematic in the merging of minds [presumably including elemental minds --Laird] to form larger minds per se, since it could be achieved simply by taking the set-theoretic union of the contents of the merging minds. My concern here is not with combination as such, but with the combination of spatially separable minds into a unified mind." Then he examines three arguments that he thinks after evaluation disqualify spatially separable minds from combining into a unified mind.

The first argument that he examines (and rejects) is one that would support the possibility of spatially separable minds, and is based in (Einstein's) relativity. It runs that "as conscious events are in time (proposition R_T), so they must be in space (R_S) since relativity melds time and space inextricably in spacetime". He rejects this argument for localisation on the basis that it "rests on the premise that a physical event can cause a mental one" whereas under the theory of mental monism, "physical events cannot cause mental ones": relativity applies only to events in the rendered physical world, a construct, and not to the real mental events that subvene on that rendered world.

Recognising that this argument assumes the truth of mental monism in the first place, he notes that his second argument, also based on relativity, does not. It runs as follows: "A mind has experiences in an absolute sequence, but [a human brain expanded to the size of the Earth’s orbit around the Sun could not], because the sequence of spacelike-separated physical events is relative to the observer’s frame of reference". He considers this expanded brain because "events in a brain of normal size are not spacelike separated", and argues that "Given two spacelike-separated brain events B₁ and B₂, in some frames of reference, B₁ will precede B₂; in some B₁ and B₂ will be simultaneous; and in some B₂ will precede B₁, depending on the velocity of the observer. Yet, if the phenomenal contents M₁ and M₂ that are associated with events B₁ and B₂ are combined into a unified mind, then M₁ and M₂ will have a determinate temporal sequence [...] and therefore the combination of spatially distributed elemental minds into a unified mind is untenable".

The third argument against spatially separable minds that he presents is the "Argument from Excision", which runs something like this: if two physically separate brain events, B₁ and B₂, correspond respectively with mental events M₁ and M₂, and the mental events are co-conscious, then on a panpsychic view there must be some further physical event B₀ that, owing to its being involved in a causal connection between B₁ and B₂, makes M₁ and M₂ co-conscious. If, though, we were to delay via surgical manipulation the onset of B₀, then we would have the paradoxical situation in which M₁ and M₂ become retrospectively co-conscious some time after the brain events B₁ and B₂ with which they correspond occurred, which "contradicts the principle that the macro-ordering of mental events is indubitable".

Those, then, are his arguments for a non-panpsychic (macro) mental monism / idealism. Here are some of the features he describes of that mental monism:

The simplicity of physical correlates of mind: Given his arguments against spatially separable minds, he writes that "Therefore, a mind’s correlate within the physical construct must be a spatially non-separable ‘simple’, a physical entity of some sort that, if it has parts, then those parts cannot be separated out. The nature of that simple is beyond this paper, but quantum-mechanical correlates of consciousness, such as the state of a microtubule, might work (e.g. Hameroff and Penrose 2014)."

Maximum of a singular subject: He asserts that at most one subject (of consciousness) exists. Whilst he is open to the possibility that there is no subject whatsoever (eliminativism about subjects), his arguments, he says, can also allow for the possibility of a singular subject, which "coincides with Śankara’s doctrine, that the individual Atman is non-different from the universal Brahman".

On this view, the subject is the "witness" of phenomenal experience, and whilst we naively assume each person to have a unique subject, there are no distinguishing features for each witness (as witness), and thus - if any witnesses exist - they are all identical; one and the same. He argues that physical location does not count as a distinguishing feature, since mental monism rejects physical location as other than a construct, and thus that minds cannot have a location in physical space. He also argues that whilst mental privacy fuels our intuition of a distinct subject, "It is more exact to think in terms of co-mentality than subject privacy: the phenomenal content in my mind is co-mental insofar as I have access to all of it".

Personal minds (versus the metamind): He outlines a theory of personal minds as distinct from the metamind based on "Lloyd’s (1999a) reductionist picture of mental monism". This uses set theory on sets of "experientia" - volitional acts and qualia - and defines a personal ("ordinary") mind as "a subset of the metamind, closed under ordinary operations of mental access", whereas the metamind is "the union of all existing minds". He writes of this that:

"Within mental monism, all mechanisms must be reducible to conscious volition and qualia. There is no non-mental substrate that can serve to explain vortices or dissociations. [...] Instead of metaphors from fluid dynamics and psychiatry, analogies from computer science seem more apt as it addresses and solves the same logical problems that face the metamind. In a multi-user computer, the operating system partitions memory into private areas, and each user can access only her own section of memory. Processes in different user areas communicate only through defined channels. Operating systems often achieve this with autonomous software helpers, to which software engineers refer with the evocative name of ‘daemons’.

"I therefore posit a mental daemon that interfaces the personal mind and the metamind. The daemon must have access to all of the metamind (for otherwise we must posit another daemon to explain the first daemon’s restricted access, leading to an infinite regress), and will deliver to the private mind only the experiences that are derivable from the sense organs of its avatar. An empirical implication of this hypothesis is that there could be failure modes of the daemon in which it could deliver experiences from parts of the metamind outside its sensory scope, that is, extra-sensory perception. I shall discuss this in a follow-up paper."

Here are some other miscellaneous notes on aspects of the paper that I found interesting:

The author asserts the "topic-neutrality" of physics, by which he means that it concerns only the extrinsic relations between entities, and not their intrinsic natures. He also asserts that consciousness, in contrast, concerns intrinsic natures which are directly accessible to minds. This forms the background of his argument for mental monism.

He writes of one of the most widely-used anti-physicalist arguments, by Chalmers:

"The conceivability argument says that we can conceive of a universe that is physically identical to our own, but contains no consciousness. People in this hypothetical universe behave as we do, but they are so-called ‘philosophical zombies’. If we can conceive a world that is physically identical to ours, but devoid of consciousness, then we can infer that consciousness is not a necessary concomitant of the physical workings of the brain, and so consciousness is not grounded in physics. The argument’s weakness is its assumption that we know enough about a complete physics to tell whether a zombie universe is genuinely conceivable. In particular, its premise requires that zombies have the same debates about consciousness that we have. They, too, ask what it is like to be a bat, and struggle to understand how conscious minds emerge from insentient matter. If, however, zombie philosophers were to discover, and assert, that there is nothing it is like to be a zombie, then Chalmers’ argument collapses. Conversely, if zombies do debate consciousness, then our own such debates are a sham as they too stem from neural activity only, not consciousness. Either way, the conceivability argument fails."

Finally, he acknowledges that along with micro-panpsychism, there is also the idea of "‘cosmopsychism’, associating a universal mind with the state of the whole physical universe. For example, Mathews (2011), Jaskolla and Buck (2012), Shani (2015), Nagasawa and Wager (2016). At first, this seems like an extrapolation of panpsychism, but jettisoning any structural mirroring between the physical construct and the mental world loses the core intuition of panpsychism. Cosmopsychism is another special case of mental monism, for the same reason as panpsychism is, namely because the mind cannot really be in space, which is part of a topic neutral system. Cosmopsychism is not, however, equivalent to the most general form of mental monism as the latter allows for disembodied mental entities.

"Berkeleyan idealism seems more plausible, and offers more explanatory power, than cosmopsychism, but it remains to be seen which theory is right."

[Laird]

He undertakes some analysis to define and compare panpsychism and idealism / mental monism. First, he asserts this comparison between (micro-)panpsychism and micro-idealism:

• (Pφ) (Micro-)panpsychism: The basic units of reality are fundamental physical entities, and some or all of these possess ‘elemental’ minds (not composed of smaller
  minds).
  
• (Pψ) Micro-idealism: The basic units of reality are elemental minds, and some of these possess the extrinsic relations of fundamental physical entities.
  

However, on his view that "mental locality is impossible" because there is no substantive space described by physics over and above the extrinsic relations that comprise it (physics), he finds that "Micro-idealism, therefore, is conceptually distinct from panpsychism, but the difference is superficial, not substantial."

He then arrives at (Pυ) "neutral panpsychism" in which "There is a one-to-one mapping between fundamental physical entities and elemental minds".

I am relieved to find that the author and I agree after all that panpsychism and idealism are compatible because only superficially distinct, although it seems that we have arrived at this view for somewhat different reasons. His reason seems essentially to be that the physical is not real anyway, and is merely a construct grounded in the mental, such that in a sense it's all mental anyway even when referring to the nominally physical (and its relationship with the nominally - and genuinely - mental). My reason is that that which lies beyond our immediate and apparently private mental experience is at an abstract level just structured energy through which consciousness experiences and expresses itself, and that in a sense it doesn't matter (and is perhaps even impossible to know) whether that structured energy is mental (some variety of "experience") or physical (some variety of "matter").

Pointing out that "Panpsychism’s literature lacks a principled account of ‘fundamental physical entities’", and in view of the difficulty of defining them, he defines "‘generalized neutral panpsychism’ (GPυ)" as that in which "There is a one-to-one mapping between some physical entities, not necessarily fundamental, and elemental minds."

He goes on to distinguish two versions of mental monism: "‘Monolithic mental monism’ says that the metamind is not separable into constituents corresponding to bodies; and an ‘object-oriented mental monism’ maintains the Berkeleyan thesis that the metamind is separable into encapsulated archetypes corresponding to observed physical entities. The latter is a more parsimonious model and in what follows I shall consider only object-oriented mental monism."

He finally arrives at the following normalised summary and comparison of panpsychism and mental monism, in which the last two list items are shared between microphysical panpsychism, generalised panpsychism, and object-oriented mental monism:

• There is a one-to-one mapping of:
  
  • (in microphysical panpsychism) fundamental physical entities and elemental minds;
    
  • (in generalized panpsychism) some physical entities and elemental minds;
    
  • (in object-oriented mental monism) physical entities and object-minds.
    
• The physical properties (of each physical entity) are constituted by extrinsic relations between those entities.
  
• The intrinsic properties (of each mind) are phenomenal mental qualities.
  

Of this, he writes: "We see that: microphysical panpsychism is a special case of generalized panpsychism, which is a special case of object-oriented mental monism, which is a special case of general mental monism. (We also see that micro-panpsychism and micro-idealism are equivalent.)"

It is important to note that (as I understand it), in the terms above, ordinary (human) personal minds correspond roughly to "object-minds", whereas they (ordinary human personal minds) are constituted by aggregates of "elemental minds". Thus, the key distinction that the author makes between panpsychism and idealism / mental monism is not based in the ontological status of mind and matter and the relationship between the two, but in the way that mind is individuated and/or aggregated in its relationship with matter. This is made more explicit later in the paper where the author writes that "the core intuition—shared by panpsychists and object-oriented mental monists alike—[is] that we should expect the structure of the mental world to mirror the physical world, but panpsychists and mental monists require it to be at the micro and macro levels respectively".

And so, unfortunately, it seems that the author and I agree about the compatibility of panpsychism and idealism only at the micro level. Beyond that, the author seems to see idealism as occupying the most abstract level, whereas I see a compatibility too between idealism at the macro level and panpsychism at the macro level, in the form of cosmopsychism. I covered the paper's reference to cosmopsychism in my previous post:

Finally, he acknowledges that along with micro-panpsychism, there is also the idea of "‘cosmopsychism’, associating a universal mind with the state of the whole physical universe. For example, Mathews (2011), Jaskolla and Buck (2012), Shani (2015), Nagasawa and Wager (2016). At first, this seems like an extrapolation of panpsychism, but jettisoning any structural mirroring between the physical construct and the mental world loses the core intuition of panpsychism. Cosmopsychism is another special case of mental monism, for the same reason as panpsychism is, namely because the mind cannot really be in space, which is part of a topic neutral system. Cosmopsychism is not, however, equivalent to the most general form of mental monism as the latter allows for disembodied mental entities.

"Berkeleyan idealism seems more plausible, and offers more explanatory power, than cosmopsychism, but it remains to be seen which theory is right."

Whilst I am not well-read on cosmopsychism, it seems to me that the author is mischaracterising it as "jettisoning any structural mirroring between the physical construct and the mental world". It also seems to me that for the same reason for which he recognises a compatibility between micro-panpsychism and micro-idealism (that the physical is but a construct grounded in the mental), he ought to recognise a compatibility between cosmopsychism and mental monism, including Berkeleyan idealism. Whether cosmopsychism allows for disembodied mental entities is a question that I am not well-read enough to answer, but I don't see why it couldn't allow for a type of energy with which a mental subject associates itself which is so ethereal as to qualify that subject as being "disembodied" and "mental". Acknowledging that experience (by/within minds) is some type of energy, we can - as I wrote above - at an abstract level dissolve the distinction between "physical" and "mental" energy, and thus the distinction between "embodied" and "disembodied" minds. It seems to me that our language and terms here are flexible enough to encompass these sort of possibilities.

Having established these definitions, he mounts an argument whose conclusion is that "reality is a non-panpsychist form of mental monism" (it is thus an argument for mental-physical mirroring at the macro rather than micro level). His argument has two steps: first, he argues that mental monism is true; second, he argues that panpsychism is false.

I don't think that this argument succeeds, which is not to say that its conclusion is necessarily false.

He argues for the truth of mental monism using the anti-physicalist argument that he calls his "Berkeleyan semantic argument", which he summarises thus:

"All physical terms are defined analytically in terms of undefined fundamentals, whereas all mental terms are rooted in private ostensive definition. Therefore physical terms and mental terms form disjoint sets, and so physical propositions and mental propositions are disjoint, hence no mental fact can be grounded in physical facts. This delivers the first limb of mental monism. The second limb stems from the fact that we have direct experience of mental content but not of mind-independent physical systems. This enables us to establish reference to mental entities but prevents us from making reference to those physical things. Any assertion that a mind-independent world exists is therefore an incoherent attempt to refer to what is unreferenceable, or what Berkeley termed an “unknown somewhat” (1710, §80; 1713, p 482). Therefore, the whole of physical discourse has the character of a text that refers to nothing outside itself, that is to say, it is a fiction, albeit a convenient one."

He goes on to unpack this argument at some length, and if you find the above summary difficult to follow, then I recommend reading that unpacking in the paper itself, between (inclusively) pages 21 and 29. It seems helpful though to share his conclusion, which reiterates the above summary in different words:

"Bringing these two limbs of argument together, we find: first, the domain of consciousness is not reducible to physics; second, the physical domain to which we ordinarily refer is a construct grounded in our phenomenal content; third, any attempt to refer to a mind-independent physical world is incoherent. We must conclude that reality comprises only conscious minds, and that what we take to be the physical world is a construct within this mental world."

It seems to me that the author is contending that it is a logical truth that (because physical things are unreferenceable) the physical has no mind-independent grounding and is but a (convenient) fiction. If so, then we would expect that the negation of this logical truth would entail a contradiction or at least be inconceivable, but I don't think that it does or is. I seem to be able to conceive of a physical world that is grounded, and not in the mental, and that is no mere fiction, and I seem to be able to do so without encountering a contradiction.

My view is along the lines of the author's acknowledgement midway through his argument: that "one could still argue that (as a metaphysical hypothesis) there might actually be a physical universe that may or may not have any effect on our phenomenal content. A common motivation for this is the observation that much of our phenomenal content is not under our personal control and appears to be governed by an unobservable mechanism. Why couldn’t that unobservable mechanism just be the physical universe? This leads us to the final step of the argument for mental monism."

I am not convinced that the final step of the author's argument - the putative lack of referenceability of the physical world - actually dispenses with this possibility. I think that it is fair to say that we probably don't know the ultimate nature of that which we reference in the physical world, but I don't think it's tenable to say that we necessarily cannot reference those physical entities in the first place, and thus that they do not exist as other than useful constructs. Why could our references not be tentative pointers towards genuine physical entities whose grounding and nature we simply don't know or have access to?

Also, I'm not sure how those contents of the metamind beyond our personal minds (the "physical world" of mental monism) avoid falling foul of this argument too: likewise, we don't have direct access to those either; are they not then equally as unreferenceable as a mind-independent reality would be, and, if so, then why would we assume that they are grounded in a mind and not "really physical"? Does the author's argument when carried through to its ultimate conclusion not lead to solipsism?

In arguing for the falsity of panpsychism, he first clarifies that he doesn't "see anything philosophically problematic in the merging of minds [presumably including elemental minds --Laird] to form larger minds per se, since it could be achieved simply by taking the set-theoretic union of the contents of the merging minds. My concern here is not with combination as such, but with the combination of spatially separable minds into a unified mind." Then he examines three arguments that he thinks after evaluation disqualify spatially separable minds from combining into a unified mind.

Unlike the author, I do see a philosophical problem in the merging of minds to form larger minds, even given his set-theoretic conception of minds. It seems to me that on the author's set-theoretic conception, the qualia and volitional acts of elemental minds would join in a union into the larger mind, which would have no other source of qualia and volitional acts. Thus, every quale experienced by the larger mind would originate in an elemental mind. But for many (most?) quales, this makes no sense: the quale in the larger mind could not plausibly be present in the elemental mind. Take, for example, a feeling of being hungry due to an empty-feeling stomach: this quale makes sense only for an organism large enough to have a stomach in the first place; it could not plausibly be associated with an elemental mind [ETA: of a physical entity] smaller than a stomach, and thus could not originate in one.

But I think that this is enough for one post, so I will end there.

Very interesting paper! Thanks for analyzing it, Laird.