Western philosophy is the philosophical thought and work of the Western world. Historically, the term refers to the philosophical thinking of Western culture, beginning with Hellenic (i.e. Greek) philosophy of the Pre-Socratics such as Thales (c. 624 – c. 546 BC) and Pythagoras (c. 570 – c. 495 BC), and eventually covering a large area of the globe. The word philosophy itself originated from the Hellenic: philosophia (φιλοσοφία), literally, "the love of wisdom" (φιλεῖν philein, "to love" and σοφία sophia, "wisdom").
The scope of philosophy in the ancient understanding, and the writings of (at least some of) the ancient philosophers, were all intellectual endeavors. This included the problems of philosophy as they are understood today; but it also included many other disciplines, such as pure mathematics and natural sciences such as physics, astrology, and biology (Aristotle, for example, wrote on all of these topics.)
In the pre-Socratic period, ancient philosophers first articulated questions about the "arche" (the cause or first principle) of the universe. Western Philosophy is generally said to begin in the Greek cities of western Asia Minor (Ionia) with Thales of Miletus, who was active around 585 B.C. and was responsible for the opaque dictum, "all is water." His most noted students were respectively Anaximander (all is apeiron (roughly, the unlimited)) and Anaximenes of Miletus ("all is air"). Pythagoras, from the island of Samos off the coast of Ionia, later lived at Croton in southern Italy (Magna Graecia). Pythagoreans hold that "all is number," giving formal accounts in contrast to the previous material of the Ionians. They also believe in metempsychosis, the transmigration of souls, or reincarnation.