the greatest of all novels

Pierre senses the meaning of things, though he cannot explain it to others. In the close of the Tractatus Logico-Philosophicus (1921), which was heavily influenced by Tolstoy, the great philosopher Ludwig Wittgenstein explains why that sense cannot be communicated:

6.251. The solution of the problem of life is seen in the vanishing of the problem. (Is this not why those who have found after a long period of doubt that the sense of life became clear to them have been unable to say what constituted that sense?)

6.522. There are, indeed, things that cannot be put into words. They make themselves manifest.

It is not some fact about the world that has changed for Pierre, but his sense of the world as a whole. With that new sense, Pierre’s questions are not answered but simply disappear. He has found faith—“not faith in any sort of rule, or words, or ideas” but in a God perpetually present in the very processes of life. The real sense of the Gospel words Andrei cites—“they sow not, neither do they reap”—is that God is to be found not in remote aims but in the immediate present always before one’s eyes. Pierre has learned, “not by words or reasoning, but by direct feeling, what his nurse had told him long ago: that God is here and everywhere.” Like Pierre, Tolstoy cannot answer the questions of life in words, but instead shows us from within the experience of discovering faith.

Reading War and Peace is an experience unlike that of reading any other book, except, I suppose, Anna Karenina. We move from amazement at the smallest movements of consciousness to a grand vision of life in all its endless complexity and variety. Perhaps we become convinced of this vision because we have always tacitly and unconsciously known it. Here is Tolstoyan wisdom: real insight lies not in some abstract system, which necessarily oversimplifies, but in a faith always within our grasp. The truths we seek are so difficult to discern precisely because they are hidden in plain view.

Here.