The modern title, physics, of the course of study upon which the reader is embarking reveals something of the nature of that course. The word is derived from the Latin physica, natural science, which in turn is derived from the Greek plural phusika of the adjective phusikos meaning "of or pertaining to nature." In recent decades the scope of the meaning of the word physics has narrowed considerably until it is a "science that deals with matter and energy and their interactions in the fields of mechanics, acoustics, optics, heat, electricity, magnetism, radiation, atomic structure, and nuclear phenomena." As such a definition implies, the way to know and understand what physics is, is to do physics. This, it is suggested, is the true destination of this course of study.
The earlier title of a course such as this, still found in an occasional college catalogue, is "natural philosophy." While the philosopher is the "lover of wisdom," the word "philosophy" has come to mean a "search for truth through logical reasoning" and so the name "natural philosophy" is richer in meaning--it not only tells us that our study is the study of nature but also implies that this study will be one not merely of simple observation but will also emphasize logical reasoning.
The philosopher and the physicist of today share another common link: the same man, Thales of Miletus, is claimed by each as the FATHER of his profession. His biographer, Diogenes Laertius, narrated anecdotes about him which are worthy of mention for the sake of tradition rather than fact. Two of these anecdotes are quite famous, namely, that he fell into a well or irrigation ditch while star-gazing, and that, predicting a scarcity of olives, he cornered the olive market.
Thales is said to have predicted the eclipse of the sun which, according to Herodotus' History, occured at the close of the war between the Lydians and the Medes. By astronomical calculation such an eclipse took place on May 28th, 585 B.C. Thus we know Thales must have been well known in the early part of the sixth century, B.C. He is said to have died shortly before the fall of Sardis which took place in 546 B.C.
Among the scientific activities ascribed to Thales are the construction of an almanac and the introduction of the Phoenician practice of steering a ship's course by the Little Bear. In his metaphysics, Aristotle asserts that according to Thales the earth is superimposed upon water. Most importantly, Thales declared the primary stuff of all things to be water. This is the only certain and really important point about Thales, that he conceived "things" as varying forms of one primary and ultimate element. That he assigns water as this element is merely interesting. He earned his place as FATHER from the fact that he conceives the notion of unity in difference, and endeavours to account for the evident diversity of the many.
Some other ancient philosophers are often cited among the names of scientists, particularly Aristotle (384-322 B.C.) who is well known for his extensive writings, Democritus (460-370 B.C.) who is credited with naming the atom and expounding the original atomic theory of matter, and Archimedes (287-211 B.C.) perhaps the greatest of all Greek mathematicians and scientists.