 Suppose, first, that we focus on the question of whether there are sets of rules that describe what a person and a machine “will” do in every possible set of circumstances. If the world is deterministic, then there are such rules for both persons and machines (though perhaps it is not possible to write down the rules). If the world is not deterministic, then there are no such rules for either persons or machines (since both persons and machines can be subject to non-deterministic processes in the production of their behavior). Either way, it is hard to see any reason for supposing that there is a relevant difference between people and machines that bears on the description of what they will do in all possible sets of circumstances. (Perhaps it might be said that what the objection invites us to suppose is that, even though the world is not deterministic, humans differ from digital machines precisely because the operations of the latter are indeed deterministic. But, if the world is non-deterministic, then there is no reason why digital machines cannot be programmed to behave non-deterministically, by allowing them to access input from non-deterministic features of the world.)