Cohen does not say: being is equivalent to thinking –Parmenides or Hegel might say that. He says: being is equivalent to scientific thinking. Here we see the essential difference from the Arisotelian system. For Aristotle, philosophy is concerned with the problem of being or existence, it addresses knowledge as such or existence as such. Science describes ‘that which exists’, but the sum of its descriptions, even when supplemented by a formal ‘and so on’ does not address existence as such. The ultimate problem of knowledge is to resolve what reality is. Science does not need the concepts of being or existence; its subject is the –existing- physical universe and its activities to not even implicitly posit the idea of being or existence and what that idea means. Being or existence is a theme of philosophy, of a philosophy, that is, that is not mere scientific generalisation. Aristotelianism is a pragmatic example. It does not matter, in this context, that the historical form of Aristotelianism was not sufficiently equipped to arrive at a solution to the problem. What matters is, that it became aware of the difference between philosophy and science with regard to the problem of reality and existence; and that difference cannot be reduced to an explicitly defined and supposed empirical reality.
Reality or Being – in contradistinction to the scientific conception of that which exists – is the theme of Religion. This kind of philosophy and religion have a common subject; they may even converge to the point of identity. Only this kind of philosophy is able to form the basis for a philosophy of religion, fusing religion and philosophy into a unified system. When Maimonides stated that the philosophical elucidating of the teachings of religion is a religious duty, it was this that he had in mind. For the other type of philosophy, the product of the scientific, i.e. the empiricist mentality, the only path to religious thought is one that Cohen traced out: the view of the Divine as Idea.