Aristotle distinguishes seven meanings of the Greek word physis, settling on it as the essence of things that have a source of movement within themselves. The world, for Aristotle, is a world of self-moving or self-developing things, and physis is the principle of growth and change. The view makes it easy to conceive of things as having a nisus or principle within them whereby they are drawn to actualize a potential, or to become what it is in their nature to be (see mover, unmoved). This conception of physis enables Aristotle to effect some sort of bridge between physis and nomos, or the world of what is and the world of what ought to be. However, it was this teleological conception of nature that was supplanted by the Renaissance, and by the scientific revolution of the 17th century (see Galilean world view). With the emergence of physics as a distinct discipline, philosophical reflection turned towards attempts to interpret the results of the science, and its presuppositions and methodology. In this field, there are questions of the nature of experiment, the distinction between observation and theory, the justification of induction and its methods, the nature of explanation, and the role played by falsifiability in science. Increasingly interest has turned from highly abstract models of the logical structure of physical science to a more historical and empirical concern with the dynamics of theoretical change and the nature of research programmes. Another prominent problem is to understand whether physical description is but one kind of description amongst others that we might give of the world, and to assess what peculiar authority it does, or does not, possess.

Although the nature of space and time, and of physical magnitudes such as force and mass, have always prompted philosophical reflection (see, for example, action at a distance, Zeno’s paradoxes), the onset of relativity theory and quantum mechanics provide a yet richer field for foundational conceptual questions. The peculiar nature of time, and the apparent asymmetry of time and space, become extremely puzzling if the underlying reality is best thought of in terms of a unified field of space-time. Problems brought out by the Einstein-Podolsky-Rosen thought experiment, or the example of Schrödinger’s cat, invite us to ask whether the world quantum mechanics reveals is merely strange, or so unintelligible that it is preferable to treat the theory purely in an instrumentalist spirit (see also Copenhagen interpretation).

http://web.mit.edu/afs/athena.mit.edu/user/r/e/redingtn/www/netadv/hist.html A list of online resources on the history of physics