I've gained a very patchy working knowledge via osmosis and I find introductory guides to be frustratingly slow, re-treading the same old ground over and over again, while anything more specific dives right into the deep end. I can't seem to find something which is a middle-ground, assuming a reasonable grasp of the absolute basics and helps me fill in the gaps.

What I'd love to find is a "Philosophical Map", a tree-like structure which links philosphies together based on the answers each gives to the questions raised by the previous one. I've come to understand that any given philosophy has a number of prior assumptions, answered by earlier philosophies - you can always ask a more fundamental question. The search for the "most fundamental" question, on which all subsequent philosophy hangs, is a recurring distraction of mine.

I'm currently leaning towards "Was I created with intent?"