Philosophy Phriday: Anty-Nesting and Anty-Combination

The Daily Ant hosts a weekly series, Philosophy Phridays, in which real philosophers share their thoughts at the intersection of ants and philosophy. This is the sixty-fifth contribution in the series, submitted by Dr. Luke Roelofs.

Anty-Nesting and Anty-Combination

Here’s a question: are ants conscious? Here’s another question: are ant colonies conscious? I’m not going to defend an answer to either of these questions, but I do want to defend ‘compatibilism’ about positive answers to them. I think that, whether or not ants are conscious, their being conscious wouldn’t be a problem for the colony itself being conscious; likewise, whether or not colonies are conscious, their being so wouldn’t by itself imply that their members weren’t.

Some philosophers deny this: they’re ‘incompatibilists’ about ant-consciousness and colony-consciousness, because they endorse what Eric Schwitzgebel calls an ‘anti-nesting’ principle (2015, p. 1702). For example, Hilary Putnam, in an influential early discussion of what would come to be called ‘functionalism’, stipulates, in his suggested schematic definition of ‘pain’, that “No organism capable of feeling pain possesses a decomposition into parts which separately [satisfy this definition]”, this stipulation being intended “to rule out such ‘organisms’… as swarms of bees as single pain-feelers” (1965, p. 163). Bees being just the flower-themed sisters of ants, we may assume that ant colonies are also meant to be ruled out here.

A flower-themed ant. Image: Alex Wild

Taken at face value, this might seem to imply clear absurdities: Ned Block points out that if it rules out having even one sentient part, then potentially “pregnant women and people with sentient parasites will fail to count as pain-feeling organisms” (Block 1978, p. 291). A more plausible reading would be that Putnam means to rule out cases where, as Block puts it, conscious parts of something “play a crucial role in” the whole being conscious. Even then, we might wonder what the motivation is for this principle. Unfortunately, as Schwitzgebel notes, Putnam “doesn’t explain why this possibility is absurd for actual swarms of bees, much less [for any] possible future evolutionary development of a swarm of conscious bees…” (2015, p. 1702).

A more developed defence of Anti-Nesting comes in Giulio Tononi’s explanation of what he calls ‘the exclusion principle’, part of his ‘Information Integration Theory of Consciousness’ (2009, 2012). Consciousness is integrated information, but not all integrated information is conscious; if a system is contained within a supersystem with equal or greater informational integration, or contains a subsystem with greater, it cannot be conscious. That doesn’t by itself tell us whether colonies or ants would win out, or what sort of consciousness they have, but it does guarantee that they are ‘in competition’ for consciousness. In a way that somewhat echoes the disputes Jack Samuel discusses in a prior contribution to this series, about whether to prefer individual or collective levels of explanation. The exclusion principle tells us that one level must be privileged over the other.

But why? One rationale Tononi offers for this principle is parsimony, ‘Occam’s razor’. François Kammerer, defending his own more limited anti-nesting principle, says something similar:

“[Anti-nesting] can be seen as a consequence of a broader principle that seems to be an important prima facieconstraint on our theories of consciousness: one should not needlessly multiply ascriptions of consciousness, which is itself a specialized version of Occam’s Razor.” (2015, p. 1055)

To allow nesting would be unparsimonious, since given the whole, we gain nothing explanatorily by positing additional, ‘less conscious’, complexes.

But this isn’t how we think about parsimony in other cases. Given the existence of four table legs and a tabletop attached to them, the existence of a table adds nothing: the table causes only those effects that its parts do. But we would normally never think this made it unparsimonious to accept that tables exist, though some philosophers do draw that conclusion (e.g. Merricks 2001). The normal way to think here is that recognising the existence and powers of wholes isn’t an additional posit at all, not the kind of ‘needless multiplication of entities’ that Ockham’s razor would slice at. What I’m drinking my coffee out of is both a single mug, and trillions and trillions of atoms: neither of these descriptions undermines or competes with the other.

Given the existence of six ant legs and a tabletop anthead, does an ant exist? Image: Alex Wild

Not only does the parsimony argument fail to support Tononi’s exclusion principle, there are intuitive arguments against it. My favourite example appeared in a previous post here by Schwitzgebel (another example is Block 1978, pp. 291-292). He describes the ‘Antarean Antheads’: outwardly elephantine aliens from a planet near Antares whose ‘brains’ are in fact a swarm of minute insects, individually conscious but of rudimentary intelligence, living inside a ‘mobile hive’ which their aggregate wrigglings and scent signals control intelligently just as our bodies are intelligently controlled by the aggregate synaptic firings of our trillion neurons. As Schwitzgebel argues in the paper that post excerpts, it would be grossly implausible, not to mention decidedly unfriendly, for humans to re-interpret the Antheads’ actions and utterances (in which they come across as “sanitary, friendly, and excellent conversationalists”, 2015, p. 1701) as non-conscious as soon as they discovered what their brains were made of.

I find this argument very convincing, and the parsimony argument very unconvincing. Yet there is still this sense of puzzlement that floats around the idea of minds composed of other minds. Historically, for instance, dualist philosophers like Descartes, Plotinus, and Ibn Sina have all made arguments along roughly the following lines: all material things are divisible into parts, but minds have a special unity that makes them indivisible, so they cannot be material. Not many people make this argument any more, but I think the intuitions that it draws upon are still around, and the appeal of anti-nesting principles is a manifestation of them.

Here’s something else Tononi says to justify his exclusion principle:

“No matter how hard I try, I cannot become conscious of what is going on within the modules in my brain that perform language parsing: I hear and understand an English sentence, but I have no conscious access to how the relevant part of my brain are achieving this computation, although of course they must be connected to those other parts that give rise to my present consciousness…” (2012, p. 276)

At first glance this argument seems incomplete. After all, the fact that lack conscious access to a given process doesn’t entail that the process is not itself conscious. If an ant colony is conscious, then it might not have access to all the same information that each individual ant is: why should that entail that the ants themselves aren’t conscious of that information?

I think Tononi is gesturing in the direction of the following thought: if a conscious whole had conscious parts, its consciousness would have theirs as parts, so that their streams of consciousness were elements within its stream of consciousness. Its experiences would also include their experiences, so that by attending to the experiences the whole shared with a particular part, it could ‘introspect onto someone else’s mind’. And this, we’re meant to think, is problematic.

I think this is an interesting argument, but it fails as an argument for anti-nesting, because that first step – “if a conscious whole had conscious parts, its consciousness would have theirs as parts” – is false. That’s what Block’s example of the sentient parasite illustrates: the existence of conscious parts of me doesn’t by itself guarantee any relationship between their consciousness and mine.

But Tononi’s worry here is still pointing at something important: not anti-nesting, but rather a principle I call ‘anti-combination’:

Anti-Combination: The experiential properties of a conscious subject cannot be mere combinations of the experiential properties of other subjects which compose it.

By ‘mere combinations’ I mean something like ‘composed of and fully explained by’: if my consciousness is a mere combination of three other consciousnesses, that means it’s nothing but those three, together. I think anti-combination has a grip on our imaginations, and anti-nesting principles, though they don’t follow from it, are motivated by our intuition that there’s something weird and confusing about the idea of minds entirely composed of other minds.

But guess what! I think that weird and confusing idea is actually true, and minds built out of other minds may be quite common. In fact, I just wrote a book, Combining Minds, that aims to analyse, clarify, and ultimately refute anti-combination. If you’re interested in knowing more about it, you can order it here, or read my posts about it on the Brains Blog here. If I’m right, then we ourselves may be more like ant colonies (and swarms of bees, and Antarean Antheads) than we seem.



Block, N. (1978). “Troubles with Functionalism.” Minnesota Studies in the Philosophy of Science 9:261-325.

Kammer, F. (2015). “How a Materialist Can Deny That the United States is Probably Conscious – Response to Schwitzgebel.” Philosophia 43:1047–1057.

Roelofs, L. (2019). Combining Minds. Oxford University Press.

Putnam, H. (1965). “Psychological predicates.” In W. H. Capitan & D. D. Merrill (Eds.), Art, mind, and religion. Liverpool: University of Pittsburgh Press.

Schwitzgebel, E. (2015). “If Materialism Is True, the United States Is Probably Conscious.” Philosophical Studies 172: 1697–1721.

Schwitzgebel, E. (2017). “Antarean Antheads.” The Daily Ant.

Samuel, Jack. (2018). “Unity and Antnihilation.” The Daily Ant.

Tononi, G. and Balduzzi, D. (2009). “Qualia: The Geometry of Integrated Information.” Computational Biology 5 (8): 1-24.

Tononi, G. (2012). “Integrated information theory of consciousness: an updated account.” Archives Italiennes de Biologie 150 (2-3): 56-90.


31131040_10160213255580612_4836716052191142178_n croppedDr. Luke Roelofs is a postdoc at the Ruhr-University Bochum, and certainly not a colony of ants piloting a human-shaped vehicle. He works on a bunch of things: panpsychism, collective agency, and most recently the philosophy of imagination. And, just to emphasise, not an ant colony in disguise. His current project, ‘Reason, Empathy, and the Minds of Others’, focuses on meta-ethics and social cognition, and just for the record, he is definitely human, not 20 million ants cooperating to infiltrate human academia.