<P> René Descartes' metaphysical system of mind--body dualism describes two kinds of substance: matter and mind . According to this system, everything that is "matter" is deterministic and natural--and so belongs to natural philosophy--and everything that is "mind" is volitional and non-natural, and falls outside the domain of philosophy of nature . </P> <P> Major branches of natural philosophy include astronomy and cosmology, the study of nature on the grand scale; etiology, the study of (intrinsic and sometimes extrinsic) causes; the study of chance, probability and randomness; the study of elements; the study of the infinite and the unlimited (virtual or actual); the study of matter; mechanics, the study of translation of motion and change; the study of nature or the various sources of actions; the study of natural qualities; the study of physical quantities; the study of relations between physical entities; and the philosophy of space and time . (Adler, 1993) </P> <P> Humankind's mental engagement with nature certainly predates civilization and the record of history . Philosophical, and specifically non-religious thought about the natural world, goes back to ancient Greece . These lines of thought began before Socrates, who turned from his philosophical studies from speculations about nature to a consideration of man, viz., political philosophy . The thought of early philosophers such Parmenides, Heraclitus, and Democritus centered on the natural world . In addition, three presocratic philosophers who lived in the Ionian town of Miletus (hence the Milesian School of philosophy,) Thales, Anaximander, and Anaximenes, attempted to explain natural phenomena without recourse to creation myths involving the Greek gods . They were called the physikoi (natural philosophers,) or, as Aristotle referred to them, the physiologoi . Plato followed Socrates in concentrating on man . It was Plato's student, Aristotle, who, in basing his thought on the natural world, returned empiricism to its primary place, while leaving room in the world for man . Martin Heidegger observes that Aristotle was the originator of conception of nature that prevailed in the Middle Ages into the modern era: </P> <P> The Physics is a lecture in which he seeks to determine beings that arise on their own, τὰ φύσει ὄντα, with regard to their being . Aristotelian "physics" is different from what we mean today by this word, not only to the extent that it belongs to antiquity whereas the modern physical sciences belong to modernity, rather above all it is different by virtue of the fact that Aristotle's "physics" is philosophy, whereas modern physics is a positive science that presupposes a philosophy...This book determines the warp and woof of the whole of Western thinking, even at that place where it, as modern thinking, appears to think at odds with ancient thinking . But opposition is invariably comprised of a decisive, and often even perilous, dependence . Without Aristotle's Physics there would have been no Galileo . </P>

The miletians lived during what period in the history of western philosophy