Specter of Reason

In my last post , I argued that the knowledge argument and the conceivability argument are incompatible, which is interesting if only because they are commonly supported together in attacks against physicalism. Torin Alter has just emailed me saying that Mary Z has appeared in the literature already, and even in an argument similar to--though perhaps not identical with--my own (see McGeer, 2003). I haven't read his references, so I cannot comment on any of that yet. What I want to do here is defend my incompatibility argument against possible objections, including one raised in Torin Alter's email. First, a brief review of the incompatibility argument: If zombies are conceivable, then we can conceive of Mary Z, a zombie version of the original Mary (hereafter 'Mary O'). If zombies are conceivable, then Mary Z gains knowledge when she leaves her black-and-white room. If zombies are conceivable, then Mary Z's new knowledge does not entail non-physical facts. If z...

Two of the most popular and widely discussed arguments against physicalism are the knowledge argument and the conceivability argument. The knowledge argument is often described in terms of Mary, a super-scientist who learns every physical fact there is to know about color vision before she ever sees a color. She does this by reading black-and-white books and watching black-and-white science lectures from inside a black-and-white room. When she leaves the room and enters the polychromatic world, she experiences the color red for the first time. Only then does she learn what it is like to see red. Thus, the argument goes, Mary learns new facts about color vision. These new facts cannot be physical facts, because she had learned all of those already. So there must be facts about color vision which are not physical facts. Thus, physicalism is false--not all of the facts are physical facts. One response to the knowledge argument is to reject the premise that anyone could ever learn ...

The ability hypothesis is a defense of physicalism, and it is most commonly discussed as a response to the knowledge argument. Physicalism is the view that the world is entirely physical--or, to put it another way, that all of the physical facts about the world are all of the facts about the world. Against physicalism, the knowledge argument argues that one can know all of the physical facts without knowing all of the facts. This is most popularly discussed in terms of Mary, a super-scientist who comes to learn all of the physical facts about color vision without ever seeing a color. She lives her life confined to a black-and-white room. Yet, intuition tells us that, even though she knows all of the physical facts, she does not know what it is like to see colors. When she leaves her black-and-white room and sees colors for the first time, she learns what it is like to see colors. Thus, she learns new facts--facts which obviously cannot be physical facts, because Mary had already ...