First, then, we must consider that all men are endowed with the same sort of intellect, an intellect capable of some insight at least into the nature of things; that therefore they abstract the same transcendental notions and the same widest concepts from their experience: transcendental concepts of being, unity, truth, goodness; generic concepts of substance, matter, spirit, cause, of accident, quantity, multitude, number, identity, similarity, distinction, diversity, etc. They also form the same _specific_ concepts of possible essences. Although, therefore, they may disagree and err in regard to _the application_ of those concepts, especially of the lower, richer and more complex specific concepts, to the actual data of their experience, they agree in the fact that they have those common concepts or idea-types of reality; also in the fact that when they apply those concepts _rightly_ (_i.e._ by _logically true_ judgments) to the things that make up their experience, they have so far grasped the real natures of these things; and finally in recognizing that the ontological truth of these things lies in the conformity of the latter with their true and proper mental types or essences. And just as each of these latter is one, indivisible, immutable, necessary and eternal (14, 15), so is the ontological truth of things, whether possible or actual, one, indivisible, immutable, necessary and eternal. Of course, just as the human mind does not constitute but only apprehends reality, so the human mind does not constitute the ontological truth of reality, but only apprehends it. Every reality is capable of producing in the human mind a more or less adequate mental representation of itself: in this lies what we may call the potential or fundamental ontological truth of reality. When it does produce such a mental concept of itself its relation of conformity to this concept is its formal ontological truth. Of course the human mind may err in applying to any reality a wrong concept; when it does it has so far failed to grasp the real nature of the thing and therefore the ontological truth which is really identical with this nature. But the thing still has its ontological truth, independently of the erring mind; not only fundamental truth, but also possibly formal truth in so far as it may be rightly apprehended, and thus related to its proper mental type, by other human minds. Reality itself, therefore, is not and cannot be false, as we shall see more fully later; error or falsity is an accident only of the mind interpreting reality.