Therefore...

Therefore, before dealing with the presentation and analysis of the problems of any science, one needs to have prior knowledge of a series of things: knowledge of the whatness and concept of the subject, knowledge of the existence of the subject, knowledge of principles by means of which the problems of that science are solved. Such knowledge is sometimes self evident and without need of exposition or acquisition, in which case there would be no difficulty.

But sometimes this knowledge is not self evident and needs exposition and proof. For example, it is possible that the existence of a subject (such as the spirit of man) is a matter of controversy, and it is considered possible that it is a fantasy and unreal, and in such a case its real existence must be proven. Likewise, it is possible for there to be some doubt about the principles on the basis of which the problems of a science are solved, and so it is necessary that these principles are…