When I teach, such are the times, the objection to the correspondence theory of truth often takes a form something like this: “You say thought ought to reflect how the world really is. If we think dogs are cats, we’re mistaken, because dogs are not cats. But ‘dogs’ and ‘cats’ are just words. We can define words any way that we like. If some language used the word ‘dogs’ to mean both dogs and cats, who is to say they are wrong?”
There is no need to deny that some people might speak a language in which the same word were used for both dogs and cats. But such a language would be inconvenient, for it would be missing a distinction that actually exists in reality. If speakers of the language imagined that dogs and cats were the same species just because they used the same word, “dog,” for both of them, they would be mistaken. One sort of “dog” would pant and wag its tail; another sort of “dog” would purr and lick itself clean. The first sort of “dog” would chase the second sort, but the second sort would rarely chase the first. The two sorts of “dog” would be unable to interbreed, and people who liked one sort as pets would often dislike the other. Yes, one can use words any way one wishes, but not every way of using words is fitting, because not every way corresponds to reality. Truth really does lie in the equation of intellect with thing.
The question about calling both cats and dogs “dogs” may seem silly. But there is such a thing as motivated error: Often, when people keep asking the same silly questions, there is a reason, rooted in desire. For though no one in our culture seriously proposes to call cats “dogs,” people in our culture do earnestly seek to have us all call animals “persons,” some persons “non-persons,” some non-marriages “marriages,” and so forth. Because the case for these ways of thinking is difficult to make, proponents fall back on sophisms about words meaning whatever we say they mean and about reality being whatever we want it to be. Or they resort to insults, in the fashionable psychotherapeutic style. Those who resist “saying of what is that it is not, and of what is not that it is,” are said to have a “phobia” or irrational fear.
Then again, perhaps those who warn of phobias are onto something, for a certain irrational fear does seem to be abroad. Perhaps we might call it aletheiaphobia, fear of acknowledging the truth of how things really are, logophobia, fear of the supreme Logos; or nomophobia, hostility to eternal law.