Philosophical Zombies

Someone recently joked with me about being a telepath.  Amused, I asked what I was thinking at that time.  "Something logical," I was told.  Ha!  She knew me at least that well!  This answer was too general, and anyone who regularly spends time around me could at least guess this safely.  I pressed for more detail.  As all evidence available suggested would happen, she did not actually correctly describe my then-present thoughts, content with her assertion that I was thinking something "logical."

Since I am not a telepath (unless there are no other minds, of course), I have to rely on facial expressions, behaviors, and verbal communication to inform me of the mental states of others.  But do any of these things actually demonstrate that there is even a single consciousness (mind) outside of my own?

Not at all.  Every person and animal I see might be a philosophical zombie.

In popular culture, zombies are reanimated corpses, with
entertainment sometimes portraying masses of zombies
as wandering around in apocalyptic or post-apocalyptic
situations (The Walking Dead, Call of Duty: Black Ops III).
In phenomenology and philosophy, "zombie" can refer to
a being that seems to have its own consciousness when it
actually has no interior mental life.

A philosophical zombie is a thing that seems to be animated by its own consciousness, when, in actuality, it has no mind, no consciousness; it is only a physical shell devoid of inner life.  Philosophical zombies, of course, by their very nature could never be demonstrated to exist or not exist by a creature with my limitations, since the same limitations prevent me from establishing either possibility as true.  Thus the idea of such an entity is something that is useful for epistemological and metaphysical considerations.

The notion of a philosophical zombie can be used as a hypothetical concept that establishes 1) the immateriality of consciousness (which can be proven in other ways) and 2) the inability of a person (with my limitations, at least) to prove that other minds actually exist.  The former follows necessarily from the fact that a body can be imagined without consciousness, and vice versa, and the latter follows from the fact that all people and animals besides me might be philosophical zombies.  Perhaps some of them are, or all of them, or none of them at all, but I am utterly unable to actually discover which of these possible options is the case.

As a mental exercise, thinking about philosophical zombies (also called p-zombies sometimes) can set our limitations before us and draw us into a rich contemplation about the nature of consciousness.  Since neither of these outcomes is unprofitable, reflecting on p-zombies can be both enjoyable and educational.  I cannot be a p-zombie, however--my own consciousness is infallibly certain.  I can only legitimately doubt the minds of others.