Reverting now to _real_ identity: whatever we can predicate affirmatively about a being considered as _one_, and as subject of a judgment, we regard as really identical with that being. We cannot predicate a real part of its real whole, or _vice versa_. But our concepts, when compared together in judgment, bear _logical_ relations of extension and intension to each other, that is, relations of logical part to logical whole. Thus, the _logical_ identity of subject and predicate in the affirmative judgment may be only _inadequate_.(152) But the real identity underlying the affirmative judgment is an adequate real identity. When we say, for example, that “Socrates is wise,” we mean that the object of our concept of “wisdom” is in this case really and adequately identical with the object of our concept of “Socrates”: in other words that we are conceiving one and the same real being under two distinct concepts, each of which represents, more or less adequately, the whole real being, and one of them in this case less adequately than the other.
We have to bear in mind that while considering being as one or manifold, identical or distinct, we are thinking of it in its _static_ mode, as an object of abstract thought, not in its _dynamic and kinetic_ mode as actually existing in space and time, and subject to change. It is the identity of being with itself when considered in this static, unchanging condition, that is embodied in the logical _Principle of Identity_. In order, therefore, that this principle may find its application to being or reality _as subject to actual change_—and this is the state in which _de facto_ reality is presented to us as an immediate datum of experience—we must seize upon the changing reality and think of it in an indivisible instant apart from the change to which it is actually subject; only thus does the Principle of Identity apply to it—as _being_, not as _becoming_, not _in fieri_, but _in facto esse_. The Principle of Identity, which applies to all real being, whether possible or actual, tells us simply that “a thing is what it is”. But for the understanding of actual being as subject to real change we must supplement the Principle of Identity by another principle which tells us that such an actual being not only is actually what it is (Principle of Identity), but also that it _is potentially something other than what it actually is, that it is potentially what it can become actually_ (Ch. ii.).