At this point it will be useful to interrupt our exposition of the historical development of dynamics in order to make some brief retrospective observations on how the development of the theory up to the later part of the eighteenth century carried with it an ongoing and evolving debate about the very nature of scientific explanation and scientific theory. What are the legitimate forms an explanatory account can take in science? What are the legitimate concepts that may be employed in such explanations? What are the fundamental posits of our theory, and what are the legitimate grounds by which we may justify our beliefs in the fundamental posits of our scientific account of the world?

The Aristotelian account of dynamics, and Aristotle's related account of cosmology, employed explanatory notions adopted from our pre-scientific, “intuitive” ways of answering “Why?” questions about the world around us. The ultimate origin of our employment of such explanatory structures is a worthy topic for exploration, but one we will not be able to embark on here. The notion of efficient cause presumably comes from our everyday experience, primarily, one imagines, experience of things pushing and pulling each other around. This “everyday dynamics” as it appears in our daily experience may very well be the source of our idea that explanations are to be given in terms of something like Aristotelian efficient causes. The idea of an explanation given in terms of final causes may have its origin in the fact that so much of our activity as agents is accounted for by means–ends explanations in which motives, purposes and goals play such a significant role. Again the idea that various components of living beings, their organs, all have their specific functions or roles, and that their existence must somehow be accounted for in terms of those roles, long predates science properly so-called.