Life of Homer, Thales and Aristotle

Ancient Greek science and philosophy were radical innovations, but they did not emerge from a void. This chapter will first look at the way in which the world was conceived and understood, around 800 bce , in the poems of Homer and Hesiod. These poems soon came to be taken as canonical: in archaic Greece, and right down to the end of the fifth century, to know and understand Homer and Hesiod was the accepted test of an educated person. This canonical status was not created or enforced by political or economic power. Apart from their poetic achievement, the conception of the world and of human life that they provided was one that was found convincing, authoritative, and comprehensive by successive generations. Their way of representing the world, and the god-given authority they claimed for their statements, constituted the established view, against which the Ionian proto-scientists of the sixth century were sharply reacting, but to which (not surprisingly) they were also indebted. There are no discontinuities in this kind of history, without accompanying partial continuities, which are also part of the story. It makes sense to focus, at the outset, exclusively on Homer and Hesiod, but the reader should remember that they were not the products of a static or self-contained society.

Thales, an engineer by trade, was the first of the Seven Sages, or wise men of Ancient Greece. Thales is known as the first Greek philosopher, mathematician and scientist. He founded the geometry of lines, so is given credit for introducing abstract geometry. It is possible that Thales has been given credit for discoveries that were not really his. He is known for his theoretical as well as practical understanding of geometry. Thales is acknowledged by a number of sources as the one who defined the constellation Ursa Minor and used it for navigation. Some believe he wrote a book on navigation, but it has never been found.

Aristotle is a towering figure in ancient Greek philosophy, making contributions to logic, metaphysics, mathematics, physics, biology, botany, ethics, politics, agriculture, medicine, dance and theatre. He was a student of Plato who in turn studied under Socrates. He was more empirically-minded than Plato or Socrates and is famous for rejecting Plato’s theory of forms. Aristotle sees the universe as a scale lying between the two extremes: form without matter is on one end, and matter without form is on the other end. The passage of matter into form must be shown in its various stages in the world of nature. To do this is the object of Aristotle’s physics, or philosophy of nature. It is important to keep in mind that the passage from form to matter within nature is a movement towards ends or purposes. Everything in nature has its end and function, and nothing is without its purpose. Everywhere we find evidences of design and rational plan. No doctrine of physics can ignore the fundamental notions of motion, space, and time. Motion is the passage of matter into form, and it is of four kinds: (1) motion which affects the substance of a thing, particularly its beginning and its ending; (2) motion which brings about changes in quality; (3) motion which brings about changes in quantity, by increasing it and decreasing it; and (4) motion which brings about locomotion, or change of place. Of these the last is the most fundamental and important.
Aristotle rejects the definition of space as the void. Empty space is an impossibility. Hence, too, he disagrees with the view of Plato and the Pythagoreans that the elements are composed of geometrical figures. Space is defined as the limit of the surrounding body towards what is surrounded. Time is defined as the measure of motion in regard to what is earlier and later. It thus depends for its existence upon motion. If there where no change in the universe, there would be no time. Since it is the measuring or counting of motion, it also depends for its existence on a counting mind. If there were no mind to count, there could be no time. As to the infinite divisibility of space and time, and the paradoxes proposed byZeno, Aristotle argues that space and time are potentially divisible ad infinitum, but are not actually so divided.
After these preliminaries, Aristotle passes to the main subject of physics, the scale of being. The first thing to notice about this scale is that it is a scale of values. What is higher on the scale of being is of more worth, because the principle of form is more advanced in it. Species on this scale are eternally fixed in their place, and cannot evolve over time. The higher items on the scale are also more organized. Further, the lower items are inorganic and the higher are organic. The principle which gives internal organization to the higher or organic items on the scale of being is life, or what he calls the soul of the organism. Even the human soul is nothing but the organization of the body. Plants are the lowest forms of life on the scale, and their souls contain a nutritive element by which it preserves itself. Animals are above plants on the scale, and their souls contain an appetitive feature which allows them to have sensations, desires, and thus gives them the ability to move. The scale of being proceeds from animals to humans. The human soul shares the nutritive element with plants, and the appetitive element with animals, but also has a rational element which is distinctively our own. The details of the appetitive and rational aspects of the soul are described in the following two sections.