I think logic is more a proxy or a heuristic. It helps you make conjectures about the world even if you don't necessarily have direct evidence.
But if your observations contradict your logic? Something must be wrong. It could easily be the observations, but the more you have, the less likely it is. I think, at the very limit, deduction would have to give way to induction.
This happened to Kant. In Critique of Pure Reason, he presents Euclidean geometry as a set of incontestable, fundamental truths that human beings understand intuitively, and uses that as a launching point to argue for the existence of an ideal universe outside of our own perceptions and experience. Problem is, Euclid's parallel postulate is contradicted by observable evidence, as per general relativity. Other fundamental logical ideas about causality seem to be contradicted by experiments involving quantum mechanics. For science to work, though, we do have to take one thing on faith: That the universe can be understood through observation. Everything else, even logic, is fair game.
I'm sorry, my particular choice of words is sloppy. Ricardobeat said that "philosophy can only offer logical proof, non-observable/measureable". In this context, I assumed that "logic" really meant deduction or, at most, observations much less rigorous than science.
Now, assuming that by "logic" I really mean reasoning without observations, I hope my point becomes more clear. My impression is that philosophers do not really go in for scientific studies and experiments; if an idea proved logically by a philosopher contradicted sufficiently good experimental evidence, for some value of "sufficiently good", I would side with the evidence.
Hopefully my thinking is clearer now. I'm working on improving my writing, so hopefully I'll be less needlessly ambiguous in the future :).
But if your observations contradict your logic? Something must be wrong. It could easily be the observations, but the more you have, the less likely it is. I think, at the very limit, deduction would have to give way to induction.
reply