Axiomatic concepts identify explicitly what is merely implicit in the consciousness of an infant or of an animal. (Implicit knowledge is passively held material which, to be grasped, requires a special focus and process of consciousness — a process which an infant learns to perform eventually, but which an animal’s consciousness is unable to perform.)
Man grasps [the concept of “existent”] implicitly on the perceptual level — i.e., he grasps the constituents of the concept “existent,” the data which are later to be integrated by that concept. It is this implicit knowledge that permits his consciousness to develop further.