ABSTRACT
The motives which have led men to become philosophers have been of various kinds. The most respectable motive was the desire to understand the world. In early days, while philosophy and science were indistinguishable, this motive predominated. Another motive which was a potent incentive in early times was the illusoriness of the senses. Such questions as: where is the rainbow? Are things really what they seem to be in sunshine or in moonlight? In more modern forms of the same problem-are things really what they look like to the naked eye or what they look like through a microscope? Such puzzles, however, very soon came to be supplemented by a larger problem. When the Greeks began to be doubtful about the Gods of Olympus, some of them sought in philosophy a substitute for traditional beliefs. Through the combination of these two motives there arose a twofold movement in philosophy: on the one hand, it was thought to show that much which passes for knowledge in everyday life is not real knowledge; and on the other hand, that there is a deeper philosophical truth which, according to most philosophers, is more consonant than our everyday beliefs with what we should wish the universe to be. In almost all philosophy doubt has been the goad and certainty has been the goal. There has been doubt about the senses, doubt about science, and doubt about theology. In some philosophers one of these has been more prominent, in others another. Philosophers have also differed widely as to the answers they have suggested to these doubts and even as to whether any answers are possible.
