Abstract

It is generally supposed that from the beginning of his inquiries, Newton applied a special method in his scholarly researches on the nature and his two influential works, Mathematical Principles of Natural Philosophy and Optics, are the product of applying such a method. However, Einstein has warned us that if want to know the physicists’ methods, we should pay attention to their actions not to their speeches. Keeping his warning in view, the author firstly attempts to evaluate Newton’s scientific methodology appeared in the different editions of his Optics. Secondly, he tries to present what Newton has done in reality, which divulges the contradictions between what he has expressed and what he has done, and which reveals that there weren’t any set of methodological principles in the beginning.