If we survey early Greek philosophy with a modern scientific eye, certain pieces of it look familiar. The pre-Socratic inquiry into the shape and arrangement of the cosmos, its origin, or its fundamental ingredients reminds us of questions still investigated in modern astrophysics, cosmology, and particle physics. However, other pieces of early philosophy look considerably more foreign. Working scientists today do not inquire whether change is logically possible or where true reality is to be found; and it would be a considerable feat to turn up, say, a physicist or chemist who worries about how to balance the respective claims of reason and observation. These matters are no longer talked about by scientists. Does it follow that the early philosophers who devoted their lives to such questions were "unscientific," perhaps even misguided or dim-witted?
This question needs to be handled with some delicacy. Surely the fact that the physikoi were concerned about some matters no longer of interest is no indictment of their enterprise; in the course of any intellectual endeavor some problems get resolved, while others go out of fashion. But the objection may go deeper than that: are there issues that are intrinsically inappropriate or illegitimate, questions that were futile from the beginning? And did Plato and the physikoi waste their time on any of these? Perhaps we can answer in this way. Themes such as the identity of the ultimate reality, the distinction between natural and supernatural, the source of order in the universe, the nature of change, and the foundations of knowledge are quite different from the explanation of small-scale observational data (say, the descent of a heavy body, a chemical reaction, or a physiological process) that have occupied scientists for the past few centuries; but to be different is not to be insignificant. At least until Isaac Newton, these larger themes demanded as much attention from the student of nature as did the problems that now fill up a university course in science. Such questions were interesting and essential precisely because they were part of the effort to create a conceptual framework and a vocabulary for investigating the world. There were foundational questions; and it is often the fate of foundational questions to seem pointless to later generations who take the foundations for granted. Today, for example, we may find the distinction between the natural and supernatural obvious; but until the distinction was carefully drawn, the investigation of nature could not properly begin.
Thus the early philosophers began at the only possible place: the beginning. They created a conception of nature that has served as the foundation of scientific belief and investigation in the intervening centuries - the conception of nature presupposed, more or less, by modern science. In the meantime many of the questions they asked have been resolved - often with rough-and-ready solutions, rather than definitive ones, but resolved sufficiently to slip from the forefront of scientific attention. As they have sunk from view, their place has been taken by a collection of much narrower investigations. If we would understand the scientific enterprise in all of its richness and complexity, we must see that its two parts - the foundation and the superstructure - are complementary and reciprocal. Modern laboratory investigation occurs within a broad conceptual framework and cannot even begin without expectations about nature or the underlying reality; in turn, the conclusions of laboratory research reflect back on these most fundamental notions, forcing refinement and (occasionally) revision. The historian's task is to appreciate the enterprise in all of its diversity. If the garden of the physikoi is situated at the beginning of the road to modern science, then the historian of science may profitably dally in its shady corners before embarking on his journey. (43ff.: emphasis added, CE)