I can't speak for anyone else, but at a certain point the experience of running surpassed in value, and by a pretty wide margin, my desire to make sense out of it.
I don't know why I run. I don't know why I race. I don't know why I compete. I don't need to know. Because running means more to me than curiosity. It goes deeper than knowledge. I run. I compete. I move on down the line. I'm a runner.
For us runners, the question of “why” is pretty moot. Not because it may not be interesting, or important, from a certain point of view, but because we’ve left the question of the meaning of running behind. After all the questions have been asked, and all the answers given, in spite of the disagreement on essences, physiology, rationales, training strategies, trail running, road racing, i-pod wearing, mid-foot striking, turnover cadences, arm carriages, Jack Daniels, Arthur Lydiard, 20 miles a week or 100, 5k or the 50k, whether it's really the Miles of Trials or the Trial of Miles, after all the words have been spoken and keyboards have been pounded, meanings given and ideologies subverted... After all this, we runners bend down and tighten the laces, open the door, brace for the cold and are renewed: another godawful, glorious, and meaningless 8 miler.