What must the world be like for this mechanistic perspective to be accurate? Clearly, there are many ways of answering this question from different metaphysical starting assumptions. And clearly, many metaphysical starting assumptions rule this world picture out as illegitimate. The clearest path forward, it would seem, is to work out precisely what one must be committed to in holding that the world is composed of a hierarchy of mechanisms and precisely what of that can be recovered on the basis of different starting assumptions.