Other Minds

The problem of other minds is the epistemological challenge of justifying belief that other persons have conscious inner experiences — that there is something it is like to be them. We observe the behavior of others; we infer minds behind the behavior. This inference is not logically compelled. A being behaviorally indistinguishable from a conscious person could, in principle, be a philosophical zombie — all behavior, no experience.

The problem matters practically as well as philosophically. It underlies debates about machine consciousness (when, if ever, is a system's behavior sufficient evidence of inner experience?), about behaviorist methodology (can behavior ever be sufficient evidence of mind?), and about the moral status of entities whose inner lives we cannot directly access — animals, infants, the severely brain-damaged.

Arguments for belief in other minds include the argument from analogy (I know I am conscious; others are physically similar; therefore they are probably conscious too) and inference to the best explanation (positing minds explains others' behavior better than any alternative). Neither is deductively certain. The problem of other minds is the epistemological twin of solipsism — both grow from the same root: the irreducible firstperson character of conscious experience, which makes it systematically resistant to third-person verification.