Philosophy
The Zombie Argument Against Physicalism
Quick fact
The term 'philosophical zombie' was popularized by philosopher David Chalmers in the 1990s, but the argument's roots trace back to earlier discussions of consciousness and property dualism.
Why this is interesting
You have a twin—identical in every physical detail—but with one difference: they have no inner conscious experience. Could such a being exist? The zombie argument claims that if it's even conceivable, then physicalism is false.