The dual existence of form is the heart and core of Thomistic noetics; it is another vitally important application of the real distinction between essence and existence. The same form exists in knowledge, and it simultaneously exists outside of knowledge. In its existence in knowledge it is called specieslikeness, similitude of the thing. In its existence outside of knowledge it is called form, inner cause of determination, perfection. Because of the fundamental dualism of existence, the same form can be immanent and transcendent, in thought and outside of thought. The act of knowing can take place in the innermost depths of the intellect and nevertheless attain things which are outside of thought, fo rthat which determines the thing determines the thought of the thing.
[John Frederick Peifer, The Concept of Thomism, Chrzastek, ed. Cluny Press (Providence, RI: 2026), p. 199.]
