Bernard Williams argues that philosophy is in some deep way akin to history. This article is a novel exploration and defense of the Williams thesis —though in a way anathema to Williams himself. The key idea is to apply a central moral from what is sometimes called the analytic philosophy of history of the 1960s to the philosophy of philosophy of today, namely, the separation of explanation and laws. I suggest that an account of causal explanation offered by David Lewis may be modified to bring out the way in which this moral applies to philosophy, and so to defend the Williams thesis. I discuss in detail the consequences of the thesis for the issue of philosophical progress and note also several further implications: for the larger context of contemporary metaphilosophy, for the relation of philosophy to other subjects, and for explaining, or explaining away, the belief that success in philosophy requires a field-specific ability or brilliance.