To what extent can we discover truths about the world through reasoning alone without science are there truths that we will never discover through reason?

One approach would be that neither reason nor scientific theory can bring us to any truth that is beyond further questioning or challenge. It is possible that nothing that is undiscoverable can be considered true by any reasonable definition of 'true', but there is something about the absolute nature of the suggestion that raises doubt. Also, attempts to categorically separate reason from science are doomed to fail; they are not identical, but they are much more alike than they are different. Pure reason is a myth. So is pure science, for that matter.