Why does T. S Eliot matter in the twenty-first century?

As with all great artists, the appeal of T. S. Eliot is timeless. More than any other poet of his day and age, he pushed back the boundaries of what poetry was capable of, showing us a different world, written in a completely different poetic language, that influenced successive generations of poets and still influences many of them today.
Eliot's contributions to poetry, not to mention drama and literary criticism, are many and various. But one of his most important was the notion of the dissociation of sensibility. This is a complex idea, but what it amounts to in basic terms is that, at some time in the seventeenth century, at the beginning of the Scientific Revolution, thought and feeling, which had previously been unified in Western culture, began to split apart. In relation to the arts, especially literature, this meant that artists increasingly chose to express only one part of themselves, either speaking through the heart or the head but not both together.
For Eliot, this was a dangerous development. Great art, he believed, can only come from a unification, a joining together, of the sensibilities, so that in writing poetry, a poet thinks his or her feelings and feels his or her thoughts. In other words, a poet should write with both the head and the heart. And that's precisely what Eliot sought to do in his own work. Even in works of great religious devotion, such as Four Quartets, there is not simply emotion, but also a profound intelligence at work, drawing on several centuries of Western intellectual heritage to give shape to Eliot's burgeoning Christian faith.
Though many critics have challenged Eliot's ideas, they have also acknowledged the suggestiveness of the dissociation of sensibility thesis. Certainly if one applies this idea to an art work, be it a painting, a poem, or a piece of music, it's striking just how many of the very greatest pieces exhibit exactly the same kind of unified sensibility that Eliot recommends. Whatever the truth of Eliot's most notable contribution to literary criticism, there can be no doubt that it does at least make us pause and think more deeply about what constitutes a great work of art. And for that, at least, we owe Eliot a profound debt of gratitude.