I. Enigma of Time WHEN WRITERS TAKE UP the knotty issue of time, they often acknowledge their frustration by invoking this famous passage from St. Augustine's Confessions: So just what he asks. If no one asks me, I know. But if I wish to explain it to anyone who asks, I know not. (1) Perhaps these same writers, once they have admitted their despair, will go on to invoke another famous line from one of Shakespeare's sonnets: And time that gave doth now his gift confound. (2) Taken together, these two passages sum up the strange paradox of time: it both inexorably ubiquitous, yet also maddeningly difficult to talk about. Lots of things, after all, are difficult on their own terms without their being familiar to us in our ordinary lives--and in fact are difficult precisely in their unfamiliarity. One thinks here of cryptography, the Latin of Duns Scotus or the Greek of Maximus the Confessor, the chemistry of polymers, Attic epigraphy, Kremlin politics. But time, weirdly, both difficult to analyze yet inescapable. As science writer Dan Falk says, The great paradox of time that it at once intimately familiar and yet deeply mysterious: nothing more central and yet so remote. To be human to be aware of the passage of time; no concept lies closer to the core of our consciousness. Yet who can say just what time is? It thoroughly intangible. We cannot see, hear, smell, taste, or touch Yet we do feel Or at least we think we feel it. (3) Despite this ineluctable dilemma, perhaps there a way out. One way of beginning to say something meaningful about time might be to look at an eighteenth-century debate between Isaac Newton and Gottfried Leibniz. Newton had claimed that time was absolute, that is, that it served as the presupposition for nondivine reality inside of which the universe was created. Leibniz disagreed and held instead that time was entirely relational, allowing one event to be related to another. In other words, without a universe of interrelated events there would be no time. Leibniz's argument rested--as did so much of his philosophy--on his most fundamental bedrock, the so-called Principle of Sufficient Reason, which says that nothing happens without there first being a reason for it to happen. In other words, this principle insists that the universe rational through and through: there can be no event without a precedent cause that brings about that event. Without a reason for it to occur, an event simply doesn't happen. Period. But for Leibniz the same principle applies, much more controversially, to God: God does nothing on a whim but always motivated by a sufficient reason for doing so. It was this principle of course that got Leibniz into so much trouble when he said that, out of all the possible worlds God could have created, he pick what he called the of all possible worlds. Any other possible world would lack a sufficient reason to exist. As everyone knows, this conclusion threw theodicy (a word he invented) into disrepute thereafter. But he was on surer ground when he invoked that same principle to dispute Newton's notion of absolute time, as Falk explains: Leibniz believed that if time were absolute--continuing even when no change observed--then time must have been passing even before God created the universe. In that case, God created the universe at some particular time. But why that particular time? Why not five minutes earlier or five minutes later? After all, in the Newtonian scheme, every moment alike. (The best that Newton's ally [Samuel] Clarke could offer in reply was that sometimes God did do certain things on a whim. That did not satisfy Leibniz, who said such a notion is plainly maintaining that God wills something, without any sufficient reason for his will.) (4) We know Leibniz's argument ultimately proved successful (albeit shorn of its reliance on the Principle of Sufficient Reason) because of Albert Einstein's later theory of relativity. …