The subject has come up in a couple blog discussions I’ve been in recently – and a few months ago I visited many more blogs discussing zombies – on whats core to the issue of zombies. Why on earth do we care about what’s logically possible, rather than what’s actually possible? I’ve waffled on this one myself to be honest. And I plan about talking about it in more detail in the future.
But the point I want to make clear in this post, is that for those who buy into zombie and inverted spectrum arguments against physicalism, the goal posts they’re aiming for aren’t something they’ve conjured up on their own that no one but they believe in, but rather they’re working off of the standard definition of physicalism the way physicalists themsleves have defined it:
(1) Physicalism is true at a possible world w iff any world which is a physical duplicate of w is a duplicate of w simpliciter.
Again, the reasoning for holding a position of physicalism framed in modal terms is an issue for a later discussion. I’m just pointing out that this is how physicalists themselves typically define their position. So David Chalmers looks for the minimal violation. Physicalism holds that it’s not logically possible for two worlds to be physically identical in every respect and vary in any other way. Chalmers says that he’s found a case where it is logically possible for two worlds to be physically identical in every respect and vary in this one particular way – the existence of mind – hence physicalism is refuted.