Tuesday, February 12, 2008

Reply to Normajean's query

Normajean: You once summarized Quine stating that physical facts do not logically entail mental facts, just as physical facts do not logically entail moral facts. Getting an "about" from an "is" is just as impossible as getting an "ought" from an is, and for much the same reason.

VR: The analogy to the problem of getting an ought from an is is mine, not Quine's. But the idea is that many people argue, and I think they are right about this, that if you add up all the physical truths, broadly conceeived, you cannot get to any conclusion like "Jones ought to stop beating his wife." The physical facts are facts of the wrong type to entail any moral truths. Such truths, if they existed would, as J. L. Mackie puts it, be queer pieces of furniture in a physicalistic world.

At the same time, if you add up all the physical facts, it doesn't seem to me that what someone's thought is about is strictly entailed. Physical facts, by their very nature, are going to underdetermine mental states like beliefs, and even just the entertaining of propositions. Whatever the state of the physical world is, it is compatible with a multiplicity of mental states, or even, with no mental states at all (in which case we'd all be zombies). Physical states don't entail the existence of determinate mental states. But, whatever exists must be determined by the physical, then it follows that there is no fact of the matter as to what our thoughts are about, and that has all sorts of disturbing implications. For example, it means that we don't literally add, subtract, multiply, divide, or take square roots of numbers.


normajean said...

ok, thanks Victor.

IlĂ­on said...

BR: "But, [IF] whatever exists must be determined by the physical, ..."

I'm thinking that the above is what you meant to write.

Jason Pratt said...

Heck, if it comes to that, some of those numbers we take square roots of are totally imaginary constructs anyway! (i.e. the square root of negative one.) Yet the relevant math absolutely doesn't make sense, and absolutely cannot be done, unless we factor in that i.


Rino said...

Hi Victor,

Nice post. What would you say to someone who attempts to naturalize intentionality in the following way:

I have the thought 'the statue of liberty is in new york'. When I was in New York, the sun reflected light off of the statue and entered into my eyes and arranged my neurons in a certain way. Whenever those neurons are activated i now have the accompanying belief that 'the statue of liberty is in new york'. Having all of the physical facts, I can explain why that thought arose because those neurons fired, and those neurons were structured in a certain way due to the physical causal sequence that occurred many years ago while in New York. Thus the thought is about the statue in new york because my neurons were structured by the light coming off of the statue many years ago.