Mental Combination


A central topic of my work has been ‘mental combination’: part-whole relations between conscious minds. Under what circumstances could one mind count as part of another? Could a complex mind be nothing over and above a collection of simpler minds interacting? How should we relate to minds that we might contain, or be contained by?


In some ways this is a surprising idea: we don't normally think about parts of ourselves, or groups of us, as even candidates forhaving conscious minds. Lots of historical philosophers have even made it definitional that minds don't have parts: they are single, simple, and perfectly unified. But in another way it should be completely unsurprising: everything else in nature shows part-whole structure, from physical objects to biological systems to social groups (hence those historical philosophers often concluded that the mind must be something immaterial and outside of nature). So accepting mental combination just means treating minds like the rest of nature.

  • Combining Minds: How to Think About Composite Subjectivity. 2019. Oxford University Press.

These ideas are developed in my first book, “Combining Minds. It connects mental combination with a diversity of other debates in philosophy (such as debates about collective intentionality, panpsychism, the extent of consciousness in nature, and the future of AI) and defends the claim that it's possible ('combinationism') against various objections. I sketch out three different forms that combinationism could take: panpsychist combinationism, functionalism combinationism, and psychological combinationism, which reflect different starting points and assumptions about what mental combination would mean and why it might matter.

Sample material (chapters 1 and 9) are available here and here; I'm happy to share additional material privately on request. You can read a review of Combining Minds by Eric Schwitzgebel here, at  Notre Dame Philosophical Reviews. And there's a series of posts I wrote about it here at Brainsblog:

1. Why Think About Composite Subjectivity?

2. Composite Subjectivity and Functional Structure

3. Composite Subjectivity and Psychological Conflict

4. Composite Subjectivity and the Panpsychic Universe

My other publications on mental combination fall into a few clusters:

1. Metaphysics of Subjects

Some are about the general metaphysical questions associated with mental combination - about how different conscious minds sould be counted and individuated, whether they can overlap with one another, whether they can share ownership of particular conscious experiences. These are questions I examine especially in chapter 2 of Combining Minds.

  • “In Defence of Phenomenal Sharing.” (co-authored with Philip Goff; forthcoming in The Phenomenology of Self-Awareness and Conscious Subjects, edited by Julien Bugnon, Martine Nida-Rümelin, and Donnchadh O’Conaill. Routledge; presented in a talk at NYU.)

A paper arguing that a single conscious experience could potentially belong to two or more different subjects, if one of those subjects was a part of the other, or they partly overlapped. This is an idea I defend at length in Combining Minds, and here we consider a range of potential counter-arguments in detail, concluding that none are persuasive.

A paper arguing that there's nothing wrong with 'manyism', the idea that many overlapping, slightly different, conscious subjects exist in one place, wherever we thought there was just one. This idea has been accused of being metaphysically, phenomenologically, and morally absurd - I argue that it is in fact perfectly plausible, as long as phenomenal sharing (see above sharing) is possible.

  • "What’s Wrong with ‘One and a Half Minds’?" (In progress; presented in a talk at ASSC satellite workshop on the split-brain; slides here)

A paper starting from consideration of the split-brain phenomenon, which is sometimes thought to contain one mind, sometimes thought to contain two minds, and sometimes thought to be somewhere in between. People sometimes say 'maybe one and a half', but immediately follow up with 'but what would that even mean?' This paper delves into that question, expanding to ask what, in general, in means to talk about 'one and a half' of something, and then explaining why conscious subjects pose special problems. (Somewhat related to a post on the iCog blog where I discuss mental combination and the split-brain phenomenon.)

2. Phenomenological Structure

Other work is are about phenomenological structure: how to analyse our consciousness itself into parts, and how to think both about their unity with one another and the 'field' they are arrayed in.

A paper arguing that the relation known as 'phenomenal unity' or 'co-consciousness', which is often thought to connect all of a given subject's experiences to all others, could also connect two distinct subjects' experiences. That is, the unity of consciousness need not be an exclusively within-subject relation, but could in principle be a between-subjects relation as well.

A paper about the popular idea that our consciousness at any given moment forms a 'field': I ask what that means, and in particular what can be said about the dimensions of this field, given the plausible thought that a field logically implies some sort of dimensions. I argue that the dimensions cannot simply be drawn from perceived space, and suggest an analysis in terms of functional 'distance' as the inverse of tendencies towards direct interaction.

  • “The Metaphysics of Gestalt Perception.” (2013 talk at the University of Winnipeg, slides available on request)

A talk about whether Gestalt experiences, often held up as having a special, indissoluble, unity, pose a problem for the 'atomistic' idea that our consciousness is formed out of many simple parts woven together. I argue they don't: both holistic and atomistic analyses of  Gestalts are equally viable, as long as we sufficiently attentive to the sorts of relationships that can obtain among elements of experience.

3. Panpsychism and the Combination Problem

Some of my papers are focused specifically on aspects of the mental combination implied by panpsychism:

This explores the ‘subject-summing problem’: how to get a single subject out of many subjects. It compares and contrasts three approaches: experience-sharing, phenomenal bonding, and subject-fusion, and suggests that a combination of the first two has thebest prospects. (These ideas are developed at more length in Combining Minds, pp.81-120.)

This examines the ‘palette problem': how to get a qualitatively diverse consciousness out of the small number of basic qualities that are  supposedly associated with the fundamental physical properties. I argue that we have familiar examples of exactly this kind of 'phenomenal blending', and thus that this problem is not a threat to panpsychism.

This address the ‘revelation problem': if my consciousness arises from trillions of simple parts, why can't I tell that by introspection? This is a problem especially because the arguments panpsychists use against physicalists often rely on a 'revelation principle': having an experience reveals the nature of how it feels. I distinguish different versions of the revelation principle, and show that the most plausible ones are compatible with panpsychism but not with physicalism.