Last week, I attended a talk by a fellow contributor to this blog -- I don't think it's good to identify her or him since I want to discuss a view I only heard. I may easily have misunderstood the view, and the view I state may or may not be the same as a view that has been published by the speaker, or may distort what the speaker wanted to make of it.
So let's call the speaker X: if X reads this and wants to correct me with or without self-identification, so much the better.
X argued against the "reductionist" idea that some sciences are more basic than others.
1. All scientific theories are representations of reality, and as such they are incomplete since any representation leaves out something.
2. Let R1 and R2 be distinct representations of reality, neither of which is translatable into the other (e.g., by bridge principles). Suppose further that there is no representation R3, such that R1 and R2 are both translatable into R3. Under such circumstances, there is no basis for saying that R1 is more basic than R2, or vice versa.
3. Since there are no bridge principles, any two sciences (e.g., physics and chemistry; neuroscience and psychology; ecology and biology) are like R1 and R2 above.
4. Therefore, no science is more basic than any other. Any two sciences are different incomplete representations of reality -- each gets at features of reality that the other leaves out.
Now, it seems to me that this is a good argument for many conclusions. For example, it is a good argument for the autonomy of chemistry, psychology, ecology and so on. Of course, this depends on establishing premise 3 for the particular case -- but let's just grant that this can be done.
Now in the discussion of X's paper, some people urged the following sort of "objection" -- it isn't really an objection; more like an independent point. They said: Look, let's grant the above argument, but couldn't it still be the case that the reality that physics investigates is ontologically prior to the reality that chemistry investigates? -- perhaps in the sense that chemistry-facts are supervenient on physics-facts, or that chemistry-facts are just physics-facts under certain combinations, or something of the sort.
X's reply, or at least the reply I thought I heard was this: well, I agree that chemistry-entities are made up out of physics-entities, but because there are no bridge principles, the supervenience claim cannot be true. After all, there is no science in which it is true.
I am unsatisfied by this. I am inclined to think that IF chemistry-entities are made up out of physics-entities, then supervenience holds. (I don't want to put too much emphasis on supervenience: the claim that every chemistry-fact is a physics-fact is good enough for me -- some "ontological" claim of this sort.)
Now, the supervenience (or inclusion) claim may be of no interest to the chemist, since s/he has autonomous methods of investigating the domain. Further, it may be of no interest to the physicist, since it is messy and, moreover, reveals very little of interest concerning the physics-domain. It may even be the case that there is no effective way of stating the supervenience relation. But this does not imply that the supervenience claim is false.
What's wrong with my intuition?