Other Minds:
The Anti-Skeptical Position


Essay by
William H. Stoddard


May 1998

Anti-skeptical arguments

A crucial aspect of Ayn Rand's philosophy is her development of an anti-skeptical position. The key to this position is her identification of axioms, or truths that cannot be rejected without committing the fallacy of the stolen concept. Rand equates the acceptance of these axioms to the affirmation that human knowledge is possible.

But she does not give equal attention to all the skeptical arguments. Skeptics classically argued against the validity of the senses, against the existence of physical objects independent of the mind, against causality; and Rand presents arguments that all these assumptions are necessary and that they are aspects of the basic affirmation of existence and consciousness. But skeptics also classically argued against the continuity of consciousness and the reliability of memory, and against the possibility of knowing that other minds exist — that other people are conscious. Rand does not offer a critique of these claims, nor affirm memory and other minds as axiomatic.

Inferring other minds

In fact, Rand does not appear to address the question of knowledge of other minds at all. This question does appear in Nathaniel Branden's early, partially philosophically focused writings, however. Branden argues that we are directly aware of our own consciousness; that we are aware of the actions we perform that proceed from the control of our consciousness over our bodies; and that, seeing other human beings perform similar actions, we are able to infer that they are controlled by consciousnesses like ours, though we can never be aware of those consciousnesses. This is, in fact, very close to the classic introspectionist paradigm in psychology.

Epistemologically, this position has significant problems. Consider, for example, a parallel position about matter: that we do not have direct knowledge of material objects, but, from experience the sensory states that those objects create by impinging on our sense organs, we infer that the objects exist. This representationalist model of perception led naturally to Berkeley's questions about how this inference could be made, and to Hume's skepticism about knowledge beyond immediate sensory awareness. And in just the same way, the claim that we do not have direct awareness of other minds, but only infer such knowledge, leads to a skepticism about the validity of this inference that was at least latent in Hume and that emerged fully in his logical positivist successors — and was popularized in some of the fiction of Robert Heinlein, who was haunted by a nightmare solipsism that gave rise to stories such as "They" and "All You Zombies." In contemporary philosophy, it is commonly accepted that any claim to know what is in another person's mind, or even to know that that mind exists, is difficult to support and needs special justification.

Dualism; physics

And metaphysically, Branden's assertion that we cannot perceive another person's consciousness, but can only infer it from its effects, comes very close to the dualism that Rand claims to reject, and goes beyond Rand's legitimate claim that consciousness as such as axiomatic. It is one thing to say that our consciousness is an axiom which no knowledge of the physical basis of human life and behavior can ever overthrow. But it is another thing to say that no physical instrumentation can ever detect consciousness. To assert this is to claim that consciousness is not and cannot be a physical state or process at all — and if this is true, then it must instead be some kind of nonphysical state or process. This is exactly the kind of approach that Leonard Peikoff rejects as rationalistic. And if we do likewise — if we leave it to scientific investigation to discover whether consciousness is a specific configuration of physical changes or something apart from such physical changes — then we are leaving open the chance that physical instruments will be able to detect and measure consciousness within a living brain.

I don't suggest that philosophy can prove by logical arguments that this can or will happen. I think it's a question to be settled by observation and experiment. In fact, I think observation and experiment have already begun to settle it — see, for example, Paul Churchland's The Engine of Reason, the Seat of the Soul, which shows a sketch of an image taken from the brain of a monkey looking at a geometric design, in which a distorted but recognizable variant of that image is spread across the neurons of the monkey's visual cortex.

Philosophy & other minds

But, beyond questions of scientific fact, I think that philosophy does have something to say about knowledge of other minds; and I think what it has to say is quite parallel to what it has to say about knowledge of physical objects or of cause and effect.

In the first place, I think it can legitimately be claimed that the existence of other minds is an axiom. At a trivial level, if X tells Y that X does not believe in the existence of other minds, Y is entitled to ask, "Who do you think you are trying to convince?" By the mere fact of engaging in philosophical discussion, we are presupposing that the other participants in the discussion are conscious. But, more generally, the existence of other minds is at the base of our knowledge, and to deny it would be to deny the possibility of knowledge.

For one thing, conceptual knowledge is embodied in propositions that are expressed in language. But language is learned from other people; even if there are valid cases of children who invented their own languages when cut off from other human beings, such cases involve at least two children using language interpersonally. Solitary children do not learn to use a language. But if we are to learn to use language to refer to the physical world, it appears that we must presuppose that the people from whom we learn it are also using it to refer to the physical world, and thus that they too are conscious.

The cognitive division of labor

More generally, consider the enormous extent of human knowledge, and how much human knowledge is needed even to think of philosophical questions such as whether other people are conscious. No one person could possibly invent all that knowledge alone, or hold it in their awareness. People may perceive and reason alone, but without a massive cognitive division of labor, they would do so in an unimaginably narrow scope. We have to accept that other people have knowledge of reality — and thus that they are able to identify reality — and thus that they are conscious. If we don't, we have no warrant to accept any beliefs that rest on what we have read, or heard in conversation. In short, the existence of other minds is an axiom, in the strongest sense: to deny that other people are conscious is to deny the basis of so much of our own knowledge that even the denial itself could not be claimed to be a valid belief. Or, to paraphrase John Galt, let the psychotic who denies that other people are conscious prove it without drawing on anything they were taught by other people.

But, in the second place, Rand also states that axioms are known by direct perception. We don't deduce that existence exists; we see it before us. We don't deduce that we are conscious; we experience consciousness. Axioms are first known by perception, and only later consciously identified and underscored as the basis of knowledge; and that underscoring is not a proof of the axioms — since any attempt to prove anything already presupposes that they are true — but a recognition that we are presupposing them and a reaffirmation of our intent to go on doing so.

It's easy to grasp that the validity of the senses can be known implicitly in this way; all knowledge starts out through sensory perception, and thus the fact that we are relying on our senses is implicit in all awareness of anything. But how can we know that other people are conscious in this way? How can we perceive consciousness in other people?

Detection, attention, theory of mind

A scientific approach to this question can be found in a book that I believe has been referred to in the Objectivism-L mailing list previously: Simon Baron-Cohen's Mindblindness. Baron-Cohen proposes that there are automatic neural mechanisms through which human beings perceive other beings, and particularly other human beings, as conscious, and that the basis for autism is the impaired functioning of some of these mechanisms. Baron-Cohen describes four such processes: intentionality detection, which identifies self-propelled motion; eye-direction detection, which identifies the focal point of another's attention; shared attention, which turns one's own attention to such a focal point, as when a baby looks in the direction of its mother's gaze; and theory-of-mind, which infers internal mental states.

Whether Baron-Cohen's account of the causes of autism is correct is a complex issue needing further research. But the idea that such automatic mechanisms operate within perception makes it comprehensible that we could perceive each other's consciousness, rather than inferring it through abstract thought. Remember that a perception is a group of sensations that are automatically retained and integrated into a whole. The fact that there is no sensory receptor for the neural activity within another brain, or for the mental activity within another mind (if the two are distinct), no more means that we cannot perceive consciousness than the fact that there is no sensory receptor for three-dimensional shape means that our brains cannot integrate sensations of light, contact, pressure, and muscular effort into a perception of shape, or that such a perception is merely a theoretical inference, or that it is open to skeptical doubts. In fact, perception of three-dimensional shape is the starting point for our knowledge of the physical world; and perception of other people as consciousness is the starting point for our knowledge of psychology, or at least a starting point for it.

The conscious cat

And once we are freed of the idea of consciousness as a mysterious hidden force, state, or process that lurks within the brain, we can see that consciousness is readily apparent to observation. Is the cat asleep or awake? I say his name, softly, and watch his ears; if they turn toward the sound of my voice, he is awake and has heard. When I see this, I see a shift in his attention — and thus I see his consciousness.

On the usual dualist or behaviorist accounts, going from the motion of the ears to the functioning of consciousness to produce that motion requires sophisticated scientific and philosophical theorizing, to such a degree that only a brilliant mind could achieve it; but, in fact, most species of animals that are preyed upon have some ability to perceive that a predator is looking at them. Consciousness is known perceptually long before it is identified conceptually.

Perception of other minds

Of course, we can be mistaken in seeing someone as conscious, just as we can be mistaken in seeing two lines as having the same length. We can certainly misperceive what specifically another person is paying attention to, or what they are thinking about it. But this no more invalidates our basic awareness that they are conscious than misperception of physical objects gives us any ground for doubt that physical objects exist.

In short, other minds can be known to exist in the same way that physical objects can be known to exist, by perception; and such perception is at the base of our knowledge long before we gain enough knowledge to identify it consciously as having the status of an axiom, which it has. And to argue for knowledge of other minds as an inference from our own introspection and from perception of other people's bodies is to grant too much validity to skeptical doubts on the subject — just as to treat physical objects as having existence inferred theoretically from our own sensations is to grant too much validity to that sort of skepticism.


© 1998 William H. Stoddard

Originally appeared on the
Objectivism-L mailing list

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