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These are all 'theories of everything' of a very different sort. (You can't usefully index library books according to the flavors of their quarks!) But in general, the reference books that need such theories fall back instead on lists of alphabetized keywords, because every other scheme ever proposed has been fraught with (even worse) redundancies and uncertainties. (Prototypical example: books of quotations sorted into themes like Angels, Animals, Baseball, Capitalism, Conformity, Democracy, Enlightenment, etc...)” source...