The Physics of War Read Free Page B

Thales, who lived from 624 to 546 BCE. He was the first to emphasize the importance of explanations based on reason, and he was particularly interested in why things happened. Because of his contributions he is sometimes referred to as the father of science. He is said to have predicted the eclipse of May 28, 585 BCE. There is some controversy about this, however, as most modern astronomers feel that such a prediction was not possible at that time. But there is no controversy about his most important contribution. At that time Greek sailors never left the sight of land because theyhad no idea how to navigate when no land was visible. Thales showed them how to use Polaris (the North Star) for navigation. He also studied the strange phenomena associated with magnetism and amber, and he took a serious interest in the phenomena of time and the basic nature of matter.
    The two major philosophers who came after Thales, namely Socrates and Plato, were both giants of rational thought, but their interest was mostly in logic, philosophy, and mathematics. Socrates was considered one of the wisest people of his time, but science was not central to his thinking. Plato, a student of Socrates, was probably most famous for his founding of the Academy of Athens.
    In 384 BCE, however, the ancient philosopher best known to us was born: Aristotle. He was highly influential in his own era, and he remains influential today. He was strongly interested in science, and he made several contributions, but because his influence has extended over such a long period of time, he is frequently regarded as someone who hindered the development of science. Nevertheless, his goals were admirable. As he stated in his writings, his main aim was to discover principles and causes of change, and not just describe them. Much of what he came up with, however, was erroneous. One of his major hypotheses was that there were four basic elements: earth, water, air, and fire. And he postulated that everything was made up in some way from these four elements. He also had a strong interest in the phenomena of motion, and he classified all motions as either “natural” or “violent.” A falling object had natural motion; a thrown object had violent motion. He also believed that everything beyond the earth—sun, moon, and stars—was made up of a fifth element he called “ether.” 5
    A number of other Greek scientists of the time also made important contributions. Eratosthenes (276–194 BCE) invented a system of latitude and longitude for the earth. He also calculated the circumference of the earth using the shadows of sticks at different positions. In particular he pointed out that if the earth was flat, there should not be shadows from vertical sticks at different positions at the same time (only one could be shadowless) when the sun was directly overhead. He used his new knowledge to calculate the circumference of the earth to be two hundred fifty thousand stadia (we're still not sure however what a stade is). He also calculated the distances of the sun and the moon, giving us first, but very approximate, estimates.
    Another important early Greek scientist was Hipparchus, who was born in 175 BCE. He gave us more accurate measurements of the distances to the sun and to the moon, and he was the first to set up a catalog of most of the visible stars.
    Physics first appeared as a result of the studies and speculations of the above philosophers. It's important to note, however, that their contributionscame almost entirely from “thought.” Experimental physics was not known at the time, and, indeed, the early philosophers did not perform any experiments in their attempts to prove their ideas. Nevertheless, even at that time they realized that there was a difference between what we call “pure physics” and “applied physics.” Pure physics is usually thought of as the accumulation of knowledge about the physical aspects of