I argue that we ought to distinguish two notions of "sufficiency." The first is the deductive notion, that of a "sufficient condition", wherein one thing is sufficient for another if and only it entails the other. The second is the ordinary language notion, in which one thing is sufficient for another when it is "enough" for the other, such that nothing more is needed. This ordinary notion of sufficiency can be developed into a distinctive notion of a "sufficient cause". I argue the resulting notion of sufficient causation comes at lower metaphysical cost than the deductive notion, and is the more relevant one for our purposes of prediction, manipulation, and understanding. I suggest that a number of problems in philosophy might be clarified by this distinction. In particular, I explain how Jaegwon Kim's causal overdetermination arguments against non-reductive accounts of mental causation seem to rely upon a confusion between these two notions of sufficiency.