 Interestingly, philosophers tend to acknowledge the apparent threat determinism poses to free will, even when they explicitly reject the view that laws are pushy explainers. Earman (1986), for example, advocates a theory of laws of nature that takes them to be simply the best system of regularities that systematizes all the events in universal history. This is the Best Systems Analysis (BSA), with roots in the work of Hume, Mill and Ramsey, and most recently refined and defended by David Lewis (1973, 1994) and by Earman (1984, 1986). (cf. entry on  laws of nature).  Yet he ends his comprehensive Primer on Determinism with a discussion of the free will problem, taking it as a still-important and unresolved issue. Prima facie this is quite puzzling, for the BSA is founded on the idea that the laws of nature are ontologically derivative, not primary; it is the events of universal history, as brute facts, that make the laws be what they are, and not vice-versa. Taking this idea seriously, the actions of every human agent in history are simply a part of the universe-wide pattern of events that determines what the laws are for this world. It is then hard to see how the most elegant summary of this pattern, the BSA laws, can be thought of as determiners of human actions. The determination or constraint relations, it would seem, can go one way or the other, not both.