  The foregoing argument makes essential use of collapse. The existence of collapse as an alternative rule governing the evolution of the quantum state controversial, and it is a scandal of quantum mechanics that we have no satisfactory understanding of why collapse (or measurement) should give rise to basic probabilities. But that said, the existence of well-confirmed probabilistic theories which cannot be plausibly reduced to any non-probabilistic theory is some evidence that there are chances. (Though the Everettian (‘many-worlds’) program of generating quantum probabilities from subjective uncertainty, without basic chance in the present sense, has recently been gaining adherents—see Barrett 1999; Wallace 2007.) Indeed, it looks like the strongest kind of evidence that there are chances. For if our best physical theories did not feature probabilities, we should have little reason to postulate them, and little reason to take chances to exist. This will become important below  (§5),  when we discuss classical physics. The conventional view of classical physics, including statistical mechanics, is that it does not involve basic probability (because the state transition dynamics is deterministic), and is not accordingly a theory that posits chances (Loewer  2001).[5]  Below, we will examine this view, as well as some of the recent challenges to this conventional view. But there is at least enough evidence from fundamental physics for the existence of chances for us to adopt it already at this point as a defensible assumption.