Tuesday, March 27, 2018

Quaeritur: Logical Vocabulary in St. Thomas' Christology


Quaeritur: In St. Thomas' Christology, I have found some logical terminology that I do not understand, especially the terms "to predicate" and "reduplication."  Would you please define the following terms for me?  Thank you.


Predication: To "predicate A of B" is literally to make term A be the predicate of term B in a sentence or proposition. So to predicate A of B equals to saying that "B is A." For example, to predicate God of Christ is to say that "Christ is God." 

Reduplication occurs when a proposition has a qualification that specifies in which regard the predicate belongs to the subject.  So for example, I am both a father and a professor, and you might want to say that I am "stern" but maybe you want to add that I am so only as a professor and not as a father. So it would be reduplication to say "Professor Romero is stern as a professor." You are 'reduplicating' the term professor. And that reduplication is not a mere redundancy: it is necessary in order to specify in what regard the predicate belongs to the subject: "Prof. Romero qua professor is stern." This is often necessary in Christology in order to specify in what regard we predicate things of Christ. So for example, we can say of Christ the following: "That man is mortal as man" or "God incarnate is immortal qua God." Even if you don't repeat the subject in the predicate, it is considered reduplication if the subject implies the term: "Christ qua man is mortal." 

Reduplication is also common in philosophy; for example, when we say that the object of metaphysics is "being qua being." 

I hope this helps.

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