A paragraph from Kant and associated discussion I added to the Wikipedia article on the Correspondence Theory of Truth in June 2006 is useful at this point, and it serves to set up a corresponding statement from Peirce that we’ll take up in due course. A version of this material survives on the InterSciWiki site:
Truth is said to consist in the agreement of knowledge with the object. According to this mere verbal definition, then, my knowledge, in order to be true, must agree with the object. Now, I can only compare the object with my knowledge by this means, namely, by taking knowledge of it. My knowledge, then, is to be verified by itself, which is far from being sufficient for truth. For as the object is external to me, and the knowledge is in me, I can only judge whether my knowledge of the object agrees with my knowledge of the object. Such a circle in explanation was called by the ancients Diallelos. And the logicians were accused of this fallacy by the sceptics, who remarked that this account of truth was as if a man before a judicial tribunal should make a statement, and appeal in support of it to a witness whom no one knows, but who defends his own credibility by saying that the man who had called him as a witness is an honourable man. (Kant, 45).
According to Kant, the definition of truth as correspondence is a “mere verbal definition”, here making use of Aristotle’s distinction between a nominal definition, a definition in name only, and a real definition, a definition that shows the true cause or essence of the thing whose term is being defined. From Kant’s account of the history, the definition of truth as correspondence was already in dispute from classical times, the “skeptics” criticizing the “logicians” for a form of circular reasoning, though the extent to which the “logicians” actually held such a theory is not evaluated in this account.
A careful analysis of what Kant is saying here can help to explain why there are so many theories of truth on the contemporary scene. In other words, why would thinkers who examine the question of truth not be satisfied to rest with this very first theory that usually comes to mind?
- Kant, Immanuel (1800), Introduction to Logic. Reprinted, Thomas Kingsmill Abbott (trans.), Dennis Sweet (intro.), Barnes and Noble, New York, NY, 2005.