The Principle of Reciprocal Identity states that if two terms are identical to a third term, they are identical to each other. Which of the following best describes its consequence?

• A. The two terms are identical to each other
• B. The two terms become unrelated
• C. The two terms are identical to the third term only
• D. The two terms must be distinct from the third term

Answer: (A)

Identity is transitive in this logic: if A is the same as C and B is the same as C, then A and B must be the same as each other. This is the substitutivity of identicals in action—two terms that share the same reference with a third term end up referring to the same thing as one another. So when both terms are identical to that third term, they are identical to each other.

That means the consequence is that the two terms are identical to each other. It would contradict this to say they are unrelated, or that they are only identical to the third term and not to each other, or that they must be distinct from the third term.