One of the fundamental, persistent, claims of wisdom traditions is that to be wise one must seek to not deceive oneself. That unsparing knowledge of oneself is a key element in wisdom.
We live in societies of ever-expanding evolutionary novelty. An expanding novelty that better understanding of our evolved selves is necessary to navigate, and increasingly so. Contagious self-deception is the opposite of what we need.
One of the adaptations from French theory that has feed into contemporary ideas about progress and social justice makes it much easier to deceive oneself. This is the characterisation of discourse as entirely self-referential; that text, language, discourse only refer to themselves. The consequence of this characterisation is that truth no longer operates as the marker of having apprehended reality. There is, in this construal of reality, no unified truth to act as a arbiter of reality.
The concept of truth is inherent in language. ‘Cat refers to a cat’ is a truth claim. What is the word for …? What is the name of …? What does that mean …? These all involve truth claims. Truth is odd, however, because it refers to a certain form of success in using words.
Words are generally defined by sorting definitions — the definition allows you to sort things into what is, or is not, referred to by the word. There may well be fuzzy cases, but even a fuzzy case is sorted into being a boundary case.
Typically, there is a set of characteristics such that if a thing has all of them, it is in the set; if it has none of them it is outside the set; and the fewer of the characteristics a thing has, the closer to being outside the set it is. With the boundary being set by the use of the word, as it evolves over time.
Truth does not work the same way as words normally do. First, it refers to a certain sort of successful use of statements and not individual words or things in the world. Second, precisely because truth refers to a certain sort of success in word use, no definition of truth will allow you to sort (merely by use of the definition) any statement into true or not true. Truth does not sort in the way words that are directly about things do.
The same also applies to knowledge, as it is about the successful apprehension of reality. No definition of knowledge will, by itself, tell you whether you have successfully apprehended reality. Whether what you have, in a particular case, is knowledge. Neither truth nor knowledge entail sorting definitions in the conventional sense.
This is not a problem of reference. Saying something is false does not mean it has failed to refer. On the contrary, it is because the reference is grasped that a judgement about a statement’s truth can be attempted. Saying a statement is nonsense often implies it has failed to refer (though it can also be used to say it has failed to refer to how the world is).
The denial that language has reference beyond itself is an adaption from Jacques Derrida. (A useful quick guide to Derrida on language is here.) As with the other French theorists, Derrida is a pre-Darwinian thinker. That is, he is post-Darwin-the-icon-of-science but not Darwinian in his thinking, he does not embrace the evolutionary lens. (Ludwig Wittgenstein’s view of language, that language is defined by use, fits much more naturally with evolutionary thinking.)
Language is a technology; a technology that assists us to act in the world across a wide range of aims or goals. Words are tools for communication, but tools that work because they enable us to act in the world more effectively — otherwise the capacity for language could not have evolved. (One reason that Noam Chomsky does not have much regard for the French theorists intellectually is that he is very much a Darwinian thinker.)
Structuring truth
Humans have certain physical characteristics, nutritional needs, cognitive structures etc. The world has various structures that operate in various structured ways. So human languages tend to develop somewhat similar structures (to the extent there are patterns in, for example, vowel shifts over time) while still evidencing considerable linguistic variety.
