St. Thomas’s adherence to the correspondence theory of truth -- that “an opinion is true or false according as it answers to the reality” -- is apt to provoke protests in our day. We are told that truth is a “social construction,” which lies not in the agreement of intellect with reality, but in mere consensus among different intellects. It would seem that even on its own terms, this consensus theory of truth could be true only if everyone agreed that it were true, for otherwise there would be no consensus. Not everyone does agree that it is true; therefore it is false.
Since the incoherency of the consensus theory seems not even to make a dent in its vogue, one wonders what kind of consensus its proponents think it does enjoy. Perhaps this kind: “Everyone I talk to thinks truth lies in consensus!”
I was once privileged to hear a lecture by a visiting scholar in defense of the consensus theory of truth. During the discussion period afterward, someone asked him quite soberly whether poisonous mushrooms would still be deadly if everyone thought they were harmless. Four things were noteworthy: First, that he said a great many erudite words in response; second, that despite these many words he never answered the question; third, that everyone recognized the evasion; and fourth, that despite recognizing the evasion, nearly everyone continued to take him seriously.