Eric’s post the other day about conceivability arguments got me thinking about Jackson’s (1982) thought experiment about Mary the color scientist–in particular, about a conversation with Justin Sytsma that I had at the PSA this past Fall. Here is a sketch of the Mary case:
- Mary is a brilliant color scientist that knows all of the neural (i.e. physical) facts about color perception.
- However, Mary has never actually experienced color, having lived her entire life in a colorless lab.
- One day Mary goes outside and sees a red object, and has a new experience, the experience of red.
As Jackson argues, Mary has seemingly learned a new fact. But she already knew, all the relevant neural/physical facts. Therefore, she was learning something over and above these facts. A phenomenal, non-physical fact. Hence, objection to physicalism.
In convo with Justin he/we/I thought up a different sort of case, which involves (we may suppose) an even more brilliant colleague of Mary, named Gary. Working in the same lab, (1) and (2) above also hold for Gary, but the following is also true of Gary:
- Gary has built a device which he has attached to his brain. This device is a complex electrode array, over higher-level visual areas (essentially, a more advanced version of this), which receives inputs regarding activation patterns (distribution, firing rates, etc.) from a computer.
- Using his knowledge of the neuroscience of color vision, Gary creates a program that provides inputs to the array such that their stimulation induces in himself an experience of red (let us say a just a crude blob of red–nothing so fancy as a red apple.)
Now, Gary seemingly learns something new as well, namely, what it is like to see red. However, for my part, I don’t find the Gary argument remotely compelling as an argument against physicalism: I find it less compelling to claim that the fact he has learned is not, in some sense, physical. But Gary’s case is, as far as I can tell, analogous to the Mary case, except that the causal route by which he gains his knowledge of red depends rather crucially on his knowledge of the neuroscience of vision.
So, if I am right that the Gary argument fails, then I find myself wondering: (i) why does the argument fail? and (ii) does the Mary argument fail for the same reason? While I find myself endorsing (ii), I am not sure what to say about (i), exactly. So, what do people think? Am I a missing something here?