The reformed subjectivist principle adopted by the philosophy of organism is merely an alternative statement of the principle of relativity (the fourth Category of Explanation). This principle states that it belongs to the nature of a 'being' that it is a potential for every 'becoming.' Thus all things are to be conceived as qualifications of actual occasions. According to the ninth Category of Explanation, how an actual entity becomes constitutes what that actual entity is. This principle states that the being of a res vera is constituted by its 'becoming.' The way in which one actual entity is qualified by other actual entities is the 'experience' of the actual world enjoyed by that actual entity, as subject. The subjectivist principle is that the whole universe consists of elements disclosed in the analysis of the experiences of subjects. Process is the becoming of experience.
Alfred North Whitehead, Process and Reality, Ch. VII, Section V
