ABSTRACT
Direct observation had always been one of the most important foundations for the knowledge of reality. In the seventeenth century the range of observable things was made far greater than ever before by the introduction of new instruments. Mechanistic philosophy offered that long-sought alternative to the Aristotelian worldview. The significance of Galileo's discoveries became the subject of a lively debate. As regards methodology, it is of crucial importance that Rene Descartes rejected the then dominant tendency in science to base knowledge primarily on ancient writings. Descartes provided an example of such mathematization in his explanation of the rainbow. Since the invention of the telescope there had been a great deal of interest in optics. Descartes’ work indicated the direction the study of nature would take from the seventeenth century onwards, but his theories were often very wide of the mark. That honour is reserved for English mathematician Isaac Newton, whose theories have stood the test of time.
