Another consequence of the indivisibility of existence and identity is that a thing cannot exist without specific attributes—that is, without some particular nature. Without a specific nature, an entity could not exist at all and indeed would not be an "entity." In particular, a human being has a specific nature. A person's choices are not made in a vacuum, and if they do not accord with the natural requirements for his or her continued life, then they will lead to self-destruction, as will be amply evidenced in this course.

The principle that every thing is itself, that "A is A," is known as the law of identity. As a corollary of that law, a thing is bound by the laws of its own nature and can only act in a manner consistent with that nature. Thus natural law is an expression of the objective and observable properties of entities—an idea common to all branches of science.