d is the material one; that thoughts, ideas and sensations are the product of matter organised in a certain way (a nervous system and a brain); that thought cannot derive its categories from itself, but only from the objective world which makes itself known to us through our senses.
The earliest Greek philosophers were known as "hylozoists" (from the Greek, meaning "Those who believe that matter is alive"). Here we have a long line of heroes who pioneered the development of thought. The Greeks discovered that the world was round, long before Columbus. They explained that humans had evolved from fishes long before Darwin. They made extraordinary discoveries in mathematics, especially geometry, which were not greatly improved upon for one and a half millennia. They invented mechanics and even built a steam engine. What was startlingly new about this way of looking at the world was that it was not religious. In complete contrast to the Egyptians and Babylonians, from whom they had learnt a lot, the Greek thinkers did not resort to gods and goddesses to explain natural phenomena. For the first time, men and women sought to explain the workings of nature purely in terms of nature. This was one of the greatest turning-points in the entire history of human thought. True science starts here. p> Aristotle, the greatest of the Ancient philosophers, can be considered a materialist, although he was not so consistent as the early hylozoists. He made a series of important scientific discoveries which laid the basis for the great achievements of the Alexandrine period of Greek science.
The Middle Ages which followed the collapse of Antiquity were a desert in which scientific thought languished for centuries. Not accidentally, this was a period dominated by the Church. Idealism was the only philosophy permitted, either as a caricature of Plato or an even worse distortion of Aristotle.
Science re-emerged triumphantly in the period of the Renaissance. It was forced to wage a fierce battle against the influence of religion (not only Catholic, but also Protestant, by the way). Many martyrs paid the price of scientific freedom with their lives. Giordano Bruno was burnt at the stake. Galileo was twice put on trial by the Inquisition, and forced to renounce his views under threat of torture.
The predominant philosophical trend of the Renaissance was materialism. In England, this took the form of empiricism, the school of thought that states that all knowledge is derived from the senses. The pioneers of this school were Francis Bacon (1561-1626), Thomas Hobbes (1588-1679) and John Locke (1632-1704). The materialist school passed from England to France where it acquired a revolutionary content. In the hands of Diderot, Rousseau, Holbach and Helvetius, philosophy became an instrument for criticising all existing society. These great thinkers prepared the way for the revolutionary overthrow of the feudal monarchy in 1789-93.
The new philosophical views stimulated the development of science, encouraging experiment and observation. The 18th century saw a great advance in science, especially mechanics. But this fact had a negative as well as a positive side. The old materialism of the 18th century was narrow and rigid, reflecting the limited development of science itself. Newton expressed the limitations of empiricism with his celebrated phrase "I make no hypotheses." This one-sided mechanical outlook ultimately proved fatal to the old materialism. Paradoxically, the great advances in philosophy after 1700 were made by idealist philosophers.
Under the impact of the French revolution, the German idealist Immanuel Kant (1724-1804) subjected all previous philosophy to a thorough criticism. Kant made important discoveries not only in philosophy and logic but in science. His nebular hypothesis of the origins of the solar system (later given a mathematical basis by Laplace) is now generally accepted as correct. In the field of philosophy, Kant's masterpiece The Critique of Pure Reason was the first work to analyse the forms of logic which had remained virtually unchanged since they were first developed by Aristotle. Kant showed the contradictions implicit in many of the most fundamental propositions of philosophy. However, he failed to resolve these contradictions ( "Antinomies" ), and finally drew the conclusion that real knowledge of the world was impossible. While we can know appearances, we can never know how things are "in themselves." p> This idea was not new. It is a theme which has recurred many times in philosophy, and is generally identified with what we call subjective idealism. This was put forward before Kant by the Irish bishop and philosopher George Berkeley and the last of the classical English empiricists, David Hume. The basic argument can be summed up as follows: "I interpret the world through my senses. Therefore, all that I kn...
