Another easy answer
As I see it, the “philosophical zombie”, a hypothetical creature that can pass as a normal human being in every way but is actually just a “brilliant robot”, entirely automatic, is simply a person with whom you do not empathise. But of course there’s more that can be said about it than that.
Daniel Dennett, the high-profile atheist and professor at Tufts University outside Boston, argues that consciousness, as we think of it, is an illusion: there just isnâ€™t anything in addition to the spongy stuff of the brain, and that spongy stuff doesnâ€™t actually give rise to something called consciousness.. Common sense may tell us thereâ€™s a subjective world of inner experience â€“ but then common sense told us that the sun orbits the Earth, and that the world was flat.
This is wrong—at least as I read it, because this point is quite subtle. Dennett does not deny “there’s a subjective world of inner experience”, he says something like “of course we genuinely do have these experiences” (I can’t look it up just now but I think it’s in the introduction to The Mind’s I). The mistake that some make is to objectify that experience. And in this I’m with Dennett, though his theories do lack certain vital elements (see my dissertation).
What Dennett would not say, but I do, is that subjectivity, and especially intersubjectivity, have for many decades been sadly undervalued in English language academic philosophy. Some philosophers, like Dennett, just “go with the flow”, others react against it by insisting that consciousness is so important it must be objectively real, but both are wrong. Consciousness is extremely important, absolutely central to us as humans, and at the same time not at all objective. Its “reality status” is inter/subjective (subjective and intersubjective).
Many people, reading Dennett, think he’s somehow denying consciousness. Both David Chalmers (see the article and the previous post) and Jaron Lanier (@Wikipedia) have suggested, only half-jokingly, that maybe Dennett is a zombie. But though they don’t realise it, what that really means is that they find themselves tending not to empathise with him, and suspect him of failing properly to empathise with others.
If we properly valued subjectivity and intersubjectivity we’d feel no need to insist that there must be an objective difference between ourselves and the philosophical zombie. If we recognised the fundamental importance of empathy we’d see that’s all it takes to make the difference.