In science the meaning of the word 'explain' suffers 【C1】______civilization's every step in search of reality. Science cannot really explain electricity, magnetism, and gravitation their effects can be 【C2】______ and predicted, but 【C3】______their nature no more is known to the modern scientist than to Thales who first 【C4】______the nature of the electrification of amber, a hard, 【C5】______ brown gum. Most contemporary physicists reject the 【C6】______ that man can ever discover 【C7】______these mysterious forces 'really' are. Electricity, Bertrand Russell says, 'is not 【C8】______thing, like St. Paul's Cathedral it is a way 【C9】______ which things behave. When we have told how things behave when they are electrified, and 【C10】______ what circumstances they are electrified, we have told all 【C1】______ to tell.' Until recently scientists would have 【C12】______of such an idea. Aristotle, for example, 【C13】______natural science dominated Western thought for two thousand years, believed that man 【C14】______rrive, at an understanding of reality by 【C15】______from self-evident principles. He felt, for example, that it is a self-evident principle that everything in the universe has its proper place, 【C16】______one can deduce that objects fall to the ground because that's where they belong, and smoke goes up because that's where it belongs. The goal of Aristotelian science was to explain 【C17】______things happen. Modem science was born when Galileo began 【C18】______to explain how things happen and thus originated the method of 【C19】______experiment which now forms the 【C20】______of scientific investigation. 【C1】