Epistemology itself is an example of a branch of philosophy that is basically unscientific. That doesn't mean it's of no worth, or anything of the sort. It just means that it makes no falsifiable predictions. This is typical of philosophy - things that are scientific end up outside the purview of philosophical argument, as a scientist can just test it at that point. All that remains in philosophy are thus the unanswered, and possibly unanswerable questions.

> The laws of logic are very clear

Clear logical laws do not imply that truth can always be reached by application of it. Differing (and untestable) premises are also problematic: see all the opposing schools of thought in various branches of philosophy.