This idea has become the foundation of modern scientific philosophy which makes no claim of attaining ultimate truth. The Greeks recognized no such limitation, and thereby stifled their progress. When one observation confirmed an axiom, they believed they had found ultimate truth and stopped thinking. Until an observation, an experience, occurs, inquiry is either speculation or a matter of faith. That is, for one to really know, one must experience.
Truth comes from the correct interpretation of the experience.
As often has been proven, free-thinking rebels are responsible for the reformation of human thought. The events which led Descartes to his conclusions3 make an interesting story which illustrates one of the mechanisms which has assisted scientists from time to time, but which science has yet to understand. Descartes was born to a noble French family. Much of the education process consisted of memorizing what the Greeks and Romans had to say. Being an intelligent and brash young fellow, at 18 Descartes declared that the whole education scheme was a farce since the only certainty he had learned in his 8 years of formal schooling was the knowledge of his own ignorance.