A question like this was posted in Askphilosophers some months ago but was never answered, so I'll try it again. What kind of knowledge is chess knowledge? Some of it is deductive (e.g., if I move this piece over there it will be checkmate, given the rules of chess), but it is not possible to assess openings and middlegames deductively, since the number of possible positions until checkmate or draw is way too large for them to be computed. Some knowledge of chess players is empirical or has empirical grounds (e.g., if I play this opening my opponent will be worse, since s/he is not used to play it), but this is not exactly "chess knowledge", it is some application of "psychology" or common sense (there is also chess history, and that's empirical). Chess is mostly a non-physical matter, it is the abstract product of some rules and their possible applications. Anyway, chess players and other chess experts seem to know many chess things about openings and middlegames. If what they know is not empirical nor deductively established, what kind of knowledge do they have? Is it possible to have inductive knowledge about non-empirical, non-physical stuff?