In 1966, at a conference at Johns Hopkins University that would turn out to be among the most consequential academic events of the 20th century, a relatively unknown French philosopher named Jacques Derrida (1930–2004) gave a paper called "Structure, Sign. and Play in the Discourse of the Human Sciences Derrida's paper was supposed to discuss structuralism. Instead, it detonated it.
For the next forty years, Derrida remained the most celebrated, the most attacked, the most misrepresented, and arguably the most consequential philosopher working in the Continental tradition. He was denied an honorary degree at Cambridge in 1992, with a group of analytic philosophers signing a letter calling his work "little better than elaborate nonsense." He was awarded the degree anyway, after a ballot of the university's senate. He had his luggage searched by Czech secret police for smuggling dissident literature (he was). He was accused by critics of relativism, nihilism, sophistry, and intellectual irresponsibility. He spent much of his career patiently insisting that his accusers had not read him.
So: what is he actually doing?
The starting point is Saussure, the same structural linguistics that informed Barthes and Lévi-Strauss. Recall: for Saussure, meaning in language is not produced by the intrinsic properties of individual signs but by the system of differences among signs. "Cat" does not mean what it does because of any natural connection between the sound and the animal; it means what it does because of how it differs from "bat," "hat," "car," and every other sign in the language. Meaning is differential and relational, not intrinsic.
Derrida accepts this differential structure of meaning, and then pushes it further than Saussure intended, in a direction Saussure would have resisted. If meaning is produced by differences among signs, and if those differences extend indefinitely through the sign system (every term is defined by its differences from other terms. Are themselves defined by their differences from still other terms, and so on without end), then meaning is never fully present in any individual sign. There is always deferral: the meaning you are looking for is always to be found in the differences from other terms, which refer to still other differences. Meaning is always deferred, never completely captured or present.
Derrida invents a new word for this structure: différance, a deliberate misspelling of the French différence that is pronounced identically (you cannot hear the difference between the two words; you can only see it in writing). The word combines two meanings of the French verb différer: to differ (spatial relation: signs differ from each other) and to defer (temporal relation: meaning is perpetually deferred, never fully arrives). The undecidability built into the word, it marks a concept that cannot be contained in either of its two components, is itself a demonstration of the concept it names.
A clarification that is philosophically essential: Derrida is not saying that texts have no meaning, that all interpretations are equally valid, or that language is just a game we can play however we like. These are the misreadings he spent decades correcting. He is making a structural claim: that the conditions of meaning in language, the differential, relational, indefinitely extending structure of the sign system, make absolute, total, self-present meaning impossible. This is not the same as saying that relative, contextual, provisional meaning is impossible. Texts do mean things. Interpretations can be more or less adequate, more or less attentive, more or less responsive to the text's own movements. But the dream of a perfectly transparent text whose meaning is fully present and requires no interpretation, the dream of a language that says exactly what it means and nothing else, is precisely that: a dream. And most of Western philosophy, Derrida argues, has been organized around that dream.
Quick reflection
Think about the last time you felt completely misunderstood — when you said something that seemed clear to you but was heard very differently by the person you were talking to. Now: which of you was right about what you meant? Can you appeal to your intention as the final authority? Can you appeal to the words themselves? What would it mean to say that the words meant something you did not intend? Does the experience of being misunderstood suggest something about the relationship between language and meaning that is not just accidental communication failure but something structural?