Vulgarity is one of those many qualities that it is easier to discern than to define; suffice it to say that there is a lot of it about, perhaps more than ever. At any rate, I notice it more, and it seems to me ever more extreme: a sign, no doubt, of advancing age.

In his essay-length book Vulgarity in Literature, published in 1930, Aldous Huxley was much exercised by the definition of vulgarity. He assumes, wrongly in my view, that if no viable definition of the phenomenon is tendered, then nothing true or useful can be said of it, and only nonsense can result. He draws an analogy with the then recent Geneva Conference for the suppression of the traffic in obscene publications:

When the Greek delegate (too Socratic by half) suggested that it might be a good thing to establish a preliminary definition of the word “obscene,” Sir Archibald Bodkin [the English Director of Public Prosecutions who, having read pages 690 to 732, banned James Joyce’s Ulysses] sprang to his feet with a protest. “There is no definition of indecent or obscene in English statute law.” The law of other countries being, apparently, no more explicit, it was unanimously decided that no definition was possible. After which, having triumphantly decided that they did not know what they were talking about, the members of the Congress settled down to their discussion.

Is this right? The question no doubt raises some of the deepest problems of philosophy. Are there primary qualities so indisputable that all other qualities are ultimately reducible to combinations of them, so that we can know for certain, at least in theory, that we are all talking about precisely the same thing? Personally, I rather doubt it. In any case, in normal discourse we do not demand that everyone defines his terms; if we did, we should become rather like those antiquarian booksellers who know everything about books except their contents. In a world of continua, words cannot be entirely categorical.

The rest is here.