Gore Vidal remarks somewhere upon the irony that George Santayana is remembered today only for his warning about forgetting. (All who remember Santayana are doomed to repeat that those who do not remember history are doomed to repeat it.) Theodor Adorno seems to have suffered a similar fate, remembered by most nonspecialists only as a German gloom-meister who pronounced that after Auschwitz, poetry could no longer be written. Few realize that what Adorno actually wrote was more complex and subject to revision in his later work.
The original quote (always taken out of context and rarely footnoted) occurs in the concluding passage of a typically densely argued 1949 essay, "Cultural Criticism and Society," reprinted as the first essay in Prisms. Here is the entire passage, from the English translation by Samuel and Shierry Weber:
The more total society becomes, the greater the reification of the mind and the more paradoxical its effort to escape reification on its own. Even the most extreme consciousness of doom threatens to degenerate into idle chatter. Cultural criticism finds itself faced with the final stage of the dialectic of culture and barbarism. To write poetry after Auschwitz is barbaric. And this corrodes even the knowledge of why it has become impossible to write poetry today. Absolute reification, which presupposed intellectual progress as one of its elements, is now preparing to absorb the mind entirely. Critical intelligence cannot be equal to this challenge as long as it confines itself to self-satisfied contemplation. (Prisms, 34)
It's a difficult passage from a difficult essay, made more difficult by being wrenched out of context. (One really must read the entire essay to understand the closing lines. If you find an inexpensive copy of Prisms in a secondhand bookstore, grab it.) Adorno's meaning, particularly what he means by the word "reification," becomes clearer when read in light of two earlier sentences in this same page-long paragraph: "In the open-air prison which the world is becoming, it is no longer so important to know what depends on what, such is the extent to which everything is one. All phenomena rigidify, become insignias of the absolute rule of that which is." Here's my paraphrase/interpretation of the key sentences: To persist, after Auschwitz, in the production of monuments of the very culture that produced Auschwitz (Adorno might have spoken of Strauss's Four Last Songs rather than generalized "poetry") is to participate by denial in the perpetuation of that barbaric culture and to participate in the process (reification) that renders fundamental criticism of that culture literally unthinkable.
This is a harsh, devastating idea, and Adorno eventually came to consider it something of an overstatement. In his late work Negative Dialectics he offers this conditional revision--a revision that is, in its own way, perhaps even more devastating than the final paragraph of "Cultural Criticism and Society." I quote from the English translation by E. B. Ashton:
Perennial suffering has as much right to expression as a tortured man has to scream; hence it may have been wrong to say that after Auschwitz you could no longer write poems. But it is not wrong to raise the less cultural question whether after Auschwitz you can go on living--especially whether one who escaped by accident, one who by rights should have been killed, may go on living. His mere survival calls for the coldness, the basic principle of bourgeois subjectivity, without which there could have been no Auschwitz; this is the drastic guilt of him who was spared. By way of atonement he will be plagued by dreams such as that he is no longer living at all, that he was sent to the ovens in 1944 and his whole existence since has been imaginary, an emanation of the insane wish of a man killed twenty years earlier. (Negative Dialectics, 362-363)
This is a great and terrible passage, philosophy written with Kafka's ice-axe, history as a nightmare from which there is only one awakening. It's impossible for me to read these lines without thinking of Primo Levi, of Jean Amery, of Paul Celan (whom Adorno may well have had in mind as he wrote). This passage deserves to be at least as well-known as the line about poetry and barbarism.