A major argument for the existence of the entities in scientific theories is that if these entities did not, on the whole, exist, the empirical adequacy of the theories would be miraculous. In other words, positing the reality of these entities, and the truth of the theories, is an inference to the best explanation, or IBE as it's abbreviated. Alan Musgrave has a new paper out in the online Rutherford Journal (which is of very high quality for an online journal) entitled "The 'Miracle Argument for Scientific Realism" which canvasses these issues.
IBE is also called "abduction", after C. S. Peirce's terminology. It works thus:
The surprising fact, C, is observed.
But if A were true, C would be a matter of course.
Hence, …A is true.
This is a common inferential move, but it is deductively invalid, so Musgrave treats it as an enthymeme, and develops a more complete argument:
It is reasonable to believe that the best available explanation of any fact is true.
F is a fact.
Hypothesis H explains F.
No available competing hypothesis explains F as well as H does.
Therefore, it is reasonable to believe that H is true.
So, he argues, that we are warranted in believing that any H that explains a fact F best, expresses the truth, and hence that the entities of H are real. Now this is a kind of theory-realism. It means that you think the best theory is true, and that the things that are posited by the theory are real. Does it mean that one has to be a realist if you use IBE and scientific explanation? Musgrave thinks it does.
His argument is this: On the "Truth Schema" (also known as Convention T) developed by Tarski, accepting the truth of a claim entails that one accepts the claimed states. So if I claim that "snow is white" is true, then I accept the disquoted statement that snow is white. Hence, says Musgrave, if I accept that H is the best theory, I accept that the best belief to have is that H is true, and therefore I accept that the things H asserts are true.
So if I accept that H is empirically adequate, I must accept that H is true, or there is no explanation going on in accepting H. In other words, if you use it, you own it. So anti-realism is not compatible with IBE.
I'm not going to deny scientific realism here. I am a scientific realist for a simple reason - scientific theories are the best explanations, and the most useful, and all the other epistemic virtues claimed on their behalf. In short, science is where the knowledge is. If we do not think that knowledge is knowledge of something, then nothing is ever of anything. That sort of constructivism is ultimately self-defeating, in my view. We are forced to believe there is a world because not believing in a world is insane.
But I wonder if Musgrave really has pained the anti-realist into a corner here. If you accept the epistemic modifier of his revised IBE, that it is "reasonable to believe" that H is true, deductively we get no further than "reasonably believing that H is true". Since Musgrave wants a deductively forceful form of IBE, then he had better not exceed the force of the conclusion here. All his argument gives us is reasonable believers in the realism of H.
The miracle argument states that the empirical adequacy of H is not reasonable unless there is a truth maker for H; that is, that there is a reason why H matches empirical observations (and why we might think that its predictions will hold in future, and why we think its generalisations are correct). Let us take a reasonable anti-realist (RAR) example, then. This RAR thinks that she is reasonable in thinking that H is true, but thinks that "being true" is a conceptual rather than objective relation between hypotheses and the world. It is her reasonable view H* that "H refers". She is epistemically warranted in believing that H*. But she is not warranted in asserting H* apart from the epistemic modal operator "It is reasonable to believe that". In short, she moves the antirealism up a level. This is sometimes called "semantic ascent" after Quine, in which "truth" is a disquotational device.
I am unsure if an anti-realist can employ IBE coherently, but Musgrave hasn't yet convinced me they cannot. Science as "saving the phenomena" often works, and it can work even when the practitioners know that their hypothesis or model is probably false. But this is an excellent paper. Go read it.
- Log in to post comments
This RAR thinks that she is reasonable in thinking that H is true, but thinks that "being true" is a conceptual rather than objective relation between hypotheses and the world.
There is a bit of a hidden recurrence here that I find problematic. After all, she is asserting that "being true" is conceptual rather than objective, but something that is "true" (at least in an empirical sense) is by definition objectively true. So objectivity is, by her calculi, also conceptual, rendering the distinction meaningless. I fail to see how such an argument can avoid falling into the pit of epistemological nihilism.
> if I accept that H is empirically adequate
Danger Will Robinson. Since van Frassen, "empirically adequate" is often used to mean "passes any relevant empirical test, past present or future". I think you're using it to mean "has passed empirical tests so far". Potential confusion lurks.
No, Musgrave means literally passes all empirical tests. He introduces a distinction between vertical leaps - from cases to generalisations - and horizontal leaps - from past to present to future. I meant it in that broader sense.
Past empirical adequacy is all I need - what happens in the future is opaque. So, "empirically adequated"?
Tyler: I think that anti-realism via disquotation is problematic, but not that it leads ineluctably to nihilism. Can you expand on this?
I think that anti-realism via disquotation is problematic, but not that it leads ineluctably to nihilism. Can you expand on this?
Well, to expand, I think the larger question surrounds her claim that "being true" is "conceptual" rather than "objective". As I said, something that is "true" in any meaningful sense is also "objective", and by such a standard "objectivity" is also "conceptual". Following the logic, everything is conceptual, and you've undermined any claim to legitimate knowledge or justified belief, which is what I understand to be nihilism. (Perhaps I am interpreting the term too broadly.)
And to clarify, when I say "everything is conceptual", I mean to say that eliminating the distinction between objective and conceptual leaves one without a means with which to objectively measure concepts. That pretty much undermined epistemology, from what I can tell.