Actually, there are a number of significant arguments against the principle of sufficient reason; you can find them in Sextus Empiricus, Hume, Wittgenstein and Nāgārjuna to name but a few. In terms of accessibility, I suppose I'd recommend starting with Hume's view, which you can read about in "David Hume: Causation" (Internet Encyclopedia of Philosophy) or "Kant and Hume on Causality" (Stanford Encyclopedia of Philosophy) , followed by Wittgenstein on rule-following, which you can read about in Wittgenstein on Rules and Private Language (Wikipedia article about Saul Kripke's book) . Of course, if you are more familiar with classical literature, you can check out Sextus Empiricus ( Outlines of Pyrrhonism , Book III, if I recall correctly); similarly, if you are more familiar with Buddhist philosophy, you can begin with Book I of the Mūlamadhyamakakārikā . EDIT: I should clarify that none