We consider one aspect of Isaac Newton's thinking as regards science. He always considered the inverse aspects of any problem. We illustrate his approach in many areas of knowledge. In philosophy of science with the roles of analysis and synthesis. In mechanics with the law gravitation. In optics with the decomposition of while light and its composition from the spectral colours. In mathematics with the method of fluxions and its opposite. We believe this way of dealing with physics and mathematics is one of the sources of his immense creativity.