How time vanishes: the more we study it, the more protean it seems

Some books elucidate their subject, mapping and sharpening its boundaries. The Clock Mirage, by the mathematician Joseph Mazur, is not one of them. Mazur is out to muddy time’s waters, dismantling the easy opposition between clock time and mental time, between physics and philosophy, between science and feeling.

That split made little sense even in 1922, when the philosopher Henri Bergson and the young physicist Albert Einstein (much against his better judgment) went head-to-head at the Société française de philosophie in Paris to discuss the meaning of relativity. (Or that was the idea. Actually they talked at complete cross-purposes.)

Einstein won. At the time, there was more novel insight to be got from physics than from psychological introspection. But time passes, knowledge accrues and fashions change. The inference (not Einstein’s, though people associate it with him) that time is a fourth dimension, commensurable with the three dimensions of space, is looking decidedly frayed.