The central and outstanding fact is that the change in the method of knowing, due to the scientific revolution begun in the sixteenth and seventeenth centuries, has been accompanied by arevolution in the attitude of man toward natural occur- rences and their interactions. This transformation means, as was intimated earlier, acomplete reversal in the traditional relationship of knowledge and action. Science advances by adopting the instruments and doings of directed practice, and the knowledge thus gained becomes ameans of the develop- ment of arts which bring nature still further into actual and potential service of human purposes and valuations.