Aristotle (384-322 BCE)
A Greek philosopher who stressed the importance of direct observations in securing facts and data. He drew conclusions from direct observations, and thus initiated the basis for a scientific method of solving problems. Earlier philosophers had a tendency to reach conclusions and then select data and facts that agreed with their conclusions. He theorized that in the living world there was a gradual change from the simple and imperfect to the more complex and perfect, thus suggesting the idea of evolution.