 Then it is very plausible that there will be some explanation, which may or may not be known at present, that explains why  (5)  is true in terms of more fundamental biochemical mechanisms or physical/chemical laws and various initial and boundary conditions. What is less obviously correct is the further idea that we can elucidate these underlying mechanisms/laws without appealing to counterfactuals. It is this further idea that is appealed to when it is claimed that it must be possible to describe a truth maker for a counterfactual like  (5)  that does not itself appeal to counterfactual or modal claims. The correctness of this idea is not guaranteed merely by the existence of an explanation in the ordinary sense for why  (5)  is true; instead it seems to depend on whether a reductivist account of laws, mechanisms, etc. in terms of non-modal primitives can be given—a matter on which the jury is still  out.[7]