This post will be about the philosophy of mind, I promise. It will take some time to get there though. We need to muck around a bit in the philosophy of science to get at the relationship between neurology and psychology, which segues right back into the mind body problem. It might be more accurate to say that relationship is the mind body problem. In any case, let's get to it.
Some scientists and philosophers believe that true theories in any of the special sciences will turn out to be reducible to theories in broader sciences. Eventually, they claim, the special science theories will reduce to theories in the broadest science: physics. Jerry Fodor disagrees with such scientists and philosophers.
That claim and Fodor's rejection thereof is subject of the explanation to follow! To be honest though, it isn't even particularly obvious what we're talking about yet. This isn't a particularly easy argument to follow, and you can know I'm not being condescending because I had quite a bit of trouble understanding it when I first went through it. In an effort to make things more clear, I'll define some terms. I'm doing this because we're friends, and friends define terms for friends.
"Special sciences" are sciences which deal with a specific subject, such as biology, meteorology, or sociology. In contrast, purely physical science deals with physical interactions in general. This xkcd illustrates the divide nicely. If you ignore that one mathematician way on the right, you can see how all the sciences are, in a sense, built upon one another. They all deal with specific subjects which in turn fall within the purview of a broader science. Sociology, for example, is the study interaction between groups people; psychology is the study of human thought, motivation, and action in general. Psychology is interested in people's actions, and sociology is interested in people's actions insofar as those people are in groups and their actions are directed at one another. Psychology is therefore a broader science than sociology because it includes, but is not limited to, all the subjects which concern sociology.
The broadest science of all is physics, which deals with physical interactions in general.
If I'm doing a decent job of this at all, the first sentences of this post should be a bit clearer now. Read them again, I guess? I'm not just going to type them again here. Good? Good.
Here's an example of the sort of interaction the aforementioned philosophers and scientists would expect to exist between a theory in a particular special science and then physical science in general. Say that meteorologists have some true theory regarding how tornadoes are formed? I mean, hypotheticals aside, they probably do, right? Anyway. One might expect that because the formation of tornadoes is a purely physical phenomenon, it should be explainable purely through physics. So whereas the meteorologists might say that a tornado is formed when a warm front hits a cold front or something, the physicists would discuss both "warm fronts" and "cold fronts" in terms of the motions of individual air and water particles. The purely physical description of how tornadoes are formed would therefore make no reference to meteorological terms, but would instead entail a longwinded description of how various particles interact with one another in a long and complicated series of motions which eventually results in the phenomenon we know as a "tornado". The meteorological explanation and the physical explanation would both be accurate-- it's just that the meteorological explanation makes use of more specific terminology which is relevant only to meteorology. The purely physical terminology, on the other hand, could be used to describe all sorts of physical phenomena.
The claim being advanced by "some philosophers and scientists" is that theories in the special sciences always reduce to theories in the physics in the way I just described. And, as I've said, Fodor disagrees.
I've already written much more than I intended. I'll have to keep you in suspense for now. Why does Fodor disagree? Why do I not know shit about tornadoes? Why would I choose a subject about which I know nothing for my example? Why didn't I at least take a cursory look at the Wikipedia article for tornadoes? Find out the answer to at least one of these questions tomorrow!
