The Zombie Argument
I’m going to present to you an argument by David Chalmers which purports to show that physicalism is false. I begin by defining terms. If one is a physicalist, then one believes that all that exists is physical—that every fact in the world can be adequately explained in terms of the physical. With regard to mental states a physicalist will say that, given all the physical facts that there are about the world, we’ll get the mental ones for free. Another way to think about this is the following: We have in front of us a pencil drawing of a bear. Now if an artist were to recreate those same pencil markings on another sheet of paper, then we’d get a drawing of a bear for free. In the same way, the physicalist will say, given all of the physical facts in our world we get the mental facts for free, too. It is this thesis which the zombie argument wants to show is false.
I now introduce the notion of a zombie world. First, what’s a zombie? The type of zombie I want to talk about is not the type you see in movies. For the purposes of this argument, zombies are exact physical duplicates of us. If there were a zombie world in which all of the physical facts about our world hold, then in that world there’d be a zombie-Torrance right now typing on his laptop. Zombie-Torrance walks, talks, looks, and acts like the Torrance in the actual world. The only difference is that zombie-Torrance has no phenomenal consciousness or phenomenal states. In fact in the hypothesized zombie world there is no consciousness present at all in anybody or anything; there’s no what-it’s-like to be, do, or feel anything—no “inner cinema” or “lens of consciousness” through which anybody views the world. Zombie-Torrance may get pinched and respond by saying “ouch!” But he doesn’t actually feel pain because, as stipulated, there are no phenomenal states in the zombie world.
The proponent of the zombie argument will first say that a zombie world is conceivable: that is, it’s conceivable that there be a world in which all of the physical facts in our world hold and that in such a world there are no phenomenal states of consciousness. The second claim is that if a zombie world is conceivable then it’s possible; this is because whatever state of affairs we can conceive of is generally something that’s at least possible. The third claim is that if a zombie world is possible, then physicalism is false. Why? Well if it’s possible that given the physical facts we don’t get the mental ones for free, it’s necessarily the case that given the physical facts we don’t get the mental facts for free. That is, if it’s possible that phenomenal consciousness is not a physical thing or process, then it’s necessarily the case that phenomenal consciousness is not something physical. Another way to think about it is this: If it’s possible that A is identical to B, then it’s necessarily the case that A is identical to B because, e.g., there is no possible circumstance in which this particular cup is not identical to this particular cup. In the same way, if it’s possible for consciousness to not be something physical, then it’s necessarily the case that consciousness is not physical; and this is enough to show that physicalism is false. My reasoning can be summarized as follows:
(1) Zombies are conceivable.
(2) If zombies are conceivable, then zombies are (metaphysically) possible.
(3) If zombies are (metaphysically) possible, then physicalism is false.
(4) Therefore, physicalism is false.
Notice that this is a valid argument. That is, if the premises really are true then the conclusion follows logically and inescapably. In order to rationally escape the conclusion, then, we’d have to argue that at least one of the premises is false. We shouldn’t deny (3), however, because this is just part of the definition of physicalism with which we are working. The physicalist will have to deny either (1) or (2). So are you a physicalist? If so, which premise do you deny, and why? (Also remember that one doesn’t need to be a physicalist to disagree with the premises.)