The predicates prefixed with the definite article that refer to one and only one individual are definite descriptions, while those prefixed with the indefinite article, some, all and so on that can refer to more than one individuals are indefinite descriptions. Can the definite descriptions identify the essence of individuals and take the place of proper names?
1. Proper name is not the essence of individuals
Let the unique philosopher indicated by a proper name Aristotle be x. You can attribute a definite description to it as follows:
X was the teacher of Alexander the Great.
But you cannot substitute the definite description the teacher of Alexander the Great for the proper name Aristotle. Therefore, even if historians should discover that no one had ever taught Alexander the Great, we will say, Aristotle was not the teacher of Alexander the Great instead of Alexander did not exist.
This indicates that the proposition, X is the teacher of Alexander the Great is not analytic and the definite description is not the essence of x. You can attribute other predicates such as the disciple of Plato, the author of the Nicomachean Ethics and so on, but none of them can be the essence of x.
How about the proper name Aristotle, then? Is it the rigid designator that essentially refers to x? No. Even if historians should discover that he was not called Aristotle those days, we will say, X was not called Aristotle instead of Alexander did not exist.
Another problem: there must have been many nameless people called Aristotle. You cannot identify x only with that name. So, Aristotle is not the essence of x.
2. The essence is the unification function
Is the essence of x the spatio-temporal existence that still remains even if you deprive it of all the predicates such as Aristotle, the teacher of Alexander the Great, the disciple of Plato and so on? No. If x does not have any predicates attributed to it, we cannot recognize it. The entity we can never recognize is not really or ideally.
Although the connection between x and predicates is accidental, x could not exist, if it were not for any predicates attributed to it. This relation is the same as that between whole and part. You cannot reduce the whole to a particular part, but the whole cannot exist without any parts.
This metaphor provides us with an important clue as to what the essence is. The essence of x is not a predicate that satisfies the blank of the analytic propositional function, X is…, but the function at the meta-level that unifies predicates. It follows that losing some predicates do not prevent x from identifying its essence so long as this function works.
3. The essential self-identity of individuals
Suppose the predicates I could know about an individual y were only three: 1. y was named Richard Rockwell, 2. y was a family therapist, 3. y majored in sociology.
- Stage 1
Later I was informed that y was not a family therapist but a college instructor. So, I judged y was a college instructor named Richard Rockwell, who majored in sociology.
- Stage 2
Later I was informed that what y majored in was not sociology but history. So, I judged y was a college instructor named Richard Rockwell, who majored in history.
- Stage 3
Later I was informed that y was called not Richard Rockwell but Allen Olsen. So, I judged y was a college instructor named Allen Olsen, who majored in history.
If the three pieces of information were given to me at once, I would conclude that y did not exist. But by replacing predicates one by one, I continued to believe in the existence of y.
This might remind you of the body identity. Metabolism replaces all the matter that composes our bodies little by little within a certain period of time. You cannot replace your body with another’s at once, but you can gradually renew your body without losing your identity.
I explained in the previous article that existence is a real being while essence is an ideal being. Existence and essence is not in the relation of substance and accident. Both of them as substance have their accidents on their levels. Namely, both in the ideal subject/predicate and the body/matter relation, substance as the whole does and does not depend on accidents as parts.