An acceptable empiricist account of laws of nature would havesignificant implications for a number of philosophical projects. For example, such an account may vitiate argumentsthat the fundamental constants of nature are divinelydesigned so that laws produce a life permittinguniverse. On an empiricist account, laws do not produce the universe but are designed by us to systematize theevents of a universe which does in fact contain life; so any ``fine tuning'' of natural law has a naturalistic explanation.But there are problems for (...) the empiricist project. This paper develops a ``perspectival'' version of the Humean bestsystem approach and argues that this version solves the standard problems faced by the empiricist project.Furthermore, the paper argues, this version is best able to answer the proponents of divine design while leaving scientificlaw a suitably objective matter.[I]t is possible tocondense the enormous mass of results to a large extent – that is to find laws which summarize...Richard Feynman It has become fashionable in some circles to argue thatscience is ultimately a sham, that we scientists read order into nature, not out of nature, and that the laws of physicsare our laws, not nature's. I believe this is arrant nonsense. You would be hard-pressed to convince a physicist thatNewton's inverse square law of gravitation is a purely cultural concoction. The laws of physics, I submit, reallyexist in the world out there, and the job of the scientist is to uncover them, not invent them. True, at any giventime, the laws you find in the textbooks are tentative and approximate, but they mirror, albeit imperfectly, a reallyexisting order in the physical world. Of course, many scientists do not recognize that in accepting the reality of anorder in nature-the existence of laws `out there' – they are adopting a theological world view. P. C. W. Davies. (shrink)

August 16, 1997 David Lewis2 has long defended an account of scientific law acceptable even to an empiricist with significant metaphysical scruples. On this account, the laws are defined to be the consequences of the best system for axiomitizing all occurrent fact. Here "best system" means the set of sentences which yields the best combination of strength of descriptive content 3 with simplicity of exposition. And occurrent facts, the facts to be systematized, are roughly the particular facts about a localized (...) space-time region that are non-modal, non-dispositional, and non-causal. Scientists providing or attempting to provide laws are plausibly seen as giving general principles that unify a body of data. Thus they organize or systematize the arrangement of occurrences. For this reason, Lewis's account has the important merits of providing contact with actual scientific practice while making sense of the standard philosophical conception that laws should be general but more than mere accidental generalizations. However, Lewis has long known about a potential problem with this account, a problem involving chance and credence.4 In a recent series of articles he, Michael Thau, and Ned Hall have developed a new formulation of the relationship between chance and credence which solves the problem. However, I will argue that these articles leave untouched and even exacerbate a closely related and more fundamental problem with the best system account, the problem of nomic necessity. Laws are supposed to be more than true; in some sense they must be true. Yet a principle's membership in the best systematization for one world seems to say nothing about its necessity, i.e., its truth at other worlds. I close by briefly describing how an alternative empiricist account may remove both problems. (shrink)

If the laws are deterministic, then standard theories of counterfactuals are forced to reject at least one of the following conditionals: 1) had you chosen differently, there would not have been a violation of the laws of nature; and 2) had you chosen differently, the initial conditions of the universe would not have been different. On the relevant readings—where we hold fixed factors causally independent of your choice—both of these conditionals appear true. And rejecting either one leads to trouble for (...) philosophical theories which rely upon counterfactual conditionals—like, for instance, causal decision theory. Here, I outline a semantics for counterfactual conditionals which allows us to accept both (1) and (2). And I discuss how this semantics deals with objections to causal decision theory from Arif Ahmed. (shrink)

This paper considers how counterfactuals should be evaluated on the assumption that determinism is true. I argue against Lewis's influential view that the actual laws of nature would have been false if something had happened that never actually happened, and in favour of the competing view that history would have been different all the way back. I argue that we can do adequate justice to our ordinary practice of relying on a wide range of historical truths in evaluating counterfactuals by (...) saying that, in typical cases, history would have been only *very slightly* different until shortly before the relevant time. The paper also draws some connections between the puzzle about counterfactuals under determinism and the debate about whether determinism entails that no-one can ever do otherwise than they in fact do. (shrink)