Philosophy of Science

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

Every morning the sun has risen. On that basis, everyone expects it to rise tomorrow. Hume's question is not whether this expectation is reasonable in some loose, practical sense, everyone has it and could hardly function without it, but whether there is any argument, any chain of reasoning, that could justify it as more than habit dressed up as knowledge. Try to supply one, and the options narrow fast. You cannot justify the inference by an argument from pure logic, because there is no contradiction in supposing the sun fails to rise tomorrow; a rising sun is not contained in the concept of yesterday's sunrise. So the justification would have to come from experience instead, from the observation that nature has been uniform in the past. But that is exactly the premise in question, restated. To argue nature will keep behaving uniformly because it has always behaved uniformly assumes the very principle, that the future resembles the past, that needs justifying, which makes the argument circular rather than a genuine proof. Hume's own answer was not skepticism about crossing the street; he thought custom and habit did the practical work perfectly well, and that no one, including Hume, actually lived as though induction might fail at any moment. What he denied was that reason alone, unaided by habit, could underwrite the inference. This leaves the whole of experimental science resting, at its foundation, on a habit rather than a proof, an uncomfortable place for a discipline that prides itself on proof, and the reason the problem of induction still opens every serious discussion of what scientific method can and cannot deliver.

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

Hume's problem does not stop laboratories from running experiments, and it is worth asking why not, since nobody has actually solved it in the sense of supplying the demonstrative proof he showed was missing. Part of the answer is practical: a habit that has never once failed, however philosophically ungrounded, is still the only tool anyone has, and refusing to use it buys nothing, since the alternative is not a better method but no method at all. Part of the answer is a change of question. Twentieth century philosophy of science largely stopped trying to justify induction directly and asked instead whether science needs it at all. One influential answer holds that science does not confirm theories by accumulating supporting instances, the way induction is usually pictured, but by trying, honestly and severely, to refute them, keeping only the theories that survive serious attempts to break them. On this picture a theory is scientific not because enough sunrises have been observed to prove the next one, but because the theory forbids something, some observation that would count against it, and has been tested against that forbidden possibility and held up. This does not answer Hume's original question so much as route around it: a surviving theory is not proven true, only not yet shown false, which turns out to be a weaker and more honest thing to claim than proof ever was. Whether this fully escapes the problem, or only restates it one level up, since a theory's past survival is itself an inductive basis for trusting its future survival, is exactly the kind of question that keeps philosophy of science a live argument rather than a settled one.