1. Biology is epistemically independent of physics:
Let’s assume that biology is not epistemically independent of physics, i.e. to know any biology we must first know something about physics. However, consider evolution as determined by natural selection and the struggle for survival. We can know about the struggle for survival and natural selection without appealing to physics — just as Darwin did when he created the theory — and hence we can fundamentally understand at least some, if not most, of biology independent of physics.
2. Physics supervenes on biology:
Whatever ability we have to comprehend is an evolved skill. Therefore any physical understanding of the world, as an instance of general comprehension, supervenes on the biology of this skill.
3. Biology is just as fundamental as physics:
If the principles involved in biology and physics are epistemically independent and each can be said to supervene on the other, then neither has theoretical primordiality.
Therefore physics is not ontologically basic.
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[This argument was inspired by a discussion over at It’s Only a Theory start by Mohan Matthen.
And I want it to be known that I HATE SUPERVENIENCE. Basically if you use supervenience regularly then you are a BAD PERSON. The only good argument that uses supervenience is one that reduces the overall usage of the word: it is my hope that the above argument will prevent people from saying that biology supervenes on physics. For every argument in which I thought that using supervenience might prove useful, I found a much, much superior argument that did not make use of the term. I know you always live to regret statements like this, but right now I don’t care.]
Are you equivocating on metaphysics and epistemology here? It seems Premise 2 should read: Knowledge of physics supervenes on biological facts. At least, that’s what you end up saying: the “ability we have to comprehend” physical facts depends on biological facts about how we evolved.
But knowledge is not what’s at stake here — your conclusion is that the physical facts themselves are not basic. Whether or not that’s true, physical facts clearly are more basic than biological facts — after all, there were physical facts well before any biological systems ever existed. Indeed, physical facts are what gave rise to biological systems in the first place.
Bryan,
The trouble isn’t actually premise 2, but premise 1. If you grant full epistemic independence of biology from physics — which I don’t see as a completely unreasonable thing to do — I think that you’ve already committed yourself to the conclusion.
You have to forget all of your physics and only rely upon evolutionary explanations. I can make you do this if you grant premise 1: I’m taking full epistemic independence quite seriously. Once you do that, it is irrelevant whether we now know how old the universe is or when life started.
Therefore no, I am not equivocating because in this instance all physical facts are actually coextensive with the biology that is required to understand them (since the biological explanation is the only thing we are considering at the moment). So any physical fact does supervene on the biology.
If you can wrap your head around that, then the conclusion holds.
Ok, so let me see if I’ve got it. First, in the background, you’ve got the following picture: each physical fact corresponds to “a possible understanding of that physical fact,” which in turn corresponds to a biological fact (like a possible brain state or something). Now, your premise 1 (epistemic independence) guarantees that I can know this biological fact — that a certain brain state corresponds to a certain understanding of a certain physical fact — without knowing any physical facts at all. (Yes, that does seem questionable.) And you take this to be enough to suggest that you can access all the physical facts by just studying the biological facts.
If I’ve got that right, it is interesting — but it seems to hinge on the assumption that “knowing brain state corresponds to a physical fact” implies that you also know the physical fact. Is that really true?
Excellent. You’re almost there.
I don’t really like ‘brain state’. I’m going to call it ‘physics imagination’. ‘Brain state’ already seems to be in line with a physical description, which I want to avoid.
The argument does not require that having such an imaginative capability implies knowing physical facts. We don’t expect physicists to know biological facts in virtue of their physical knowledge of the world, so we shouldn’t ask this of biologists.
All that is necessary is that our biology be flexible enough to describe any physical fact, just as physics must be flexible enough to describe any biological fact. When we are describing some physical phenomenon the description will come from our physics imagination, and hence the physics supervenes on that biology.