 Even if the first hurdle can be overcome, the second, namely establishing precisely what the actual laws are, may seem daunting indeed. In a sense, what we are asking for is precisely what 19th and 20th century physicists sometimes set as their goal: the Final Theory of Everything. But perhaps, as Newton said of establishing the solar system’s absolute motion, “the thing is not altogether desperate.” Many physicists in the past 60 years or so have been convinced of determinism’s falsity, because they were convinced that (a) whatever the Final Theory is, it will be some recognizable variant of the family of quantum mechanical theories; and (b) all quantum mechanical theories are non-deterministic. Both (a) and (b) are highly debatable, but the point is that one can see how arguments in favor of these positions might be mounted. The same was true in the 19th century, when theorists might have argued that (a) whatever the Final Theory is, it will involve only continuous fluids and solids governed by partial differential equations; and (b) all such theories are deterministic. (Here, (b) is almost certainly false; see Earman (1986),ch. XI). Even if we now are not, we may in future be in a position to mount a credible argument for or against determinism on the grounds of features we think we know the Final Theory must have.