did—a foppish and conniving German courtier who also ranks among the greatest intellects of all time: Gottfried Wilhelm Leibniz. The year was 1714. Leibniz, then sixty-eight, was nearing the end of a long and absurdly productive career. He had, at the same time as Newton and quite independently, invented the calculus. He had single-handedly revolutionized the science of logic. He had created a fantastic metaphysics based on an infinity of soul-like units called “monads,” and on the axiom—later cruelly mocked by Voltaire in Candide—that this is “the best of all possible worlds.” Despite his fame as a philosopher-scientist, Leibniz was left behind in Hanover when his royal employer, the elector Georg Ludwig, went to Britain to become the newly crowned King George I. Leibniz was in declining health; within two years he would be dead, expiring (according to his secretary) with the release from his body of a great cloud of noxious gas.
It was in these gloomy circumstances that Leibniz produced his final philosophical writings, among them an essay titled “Principles of Nature and Grace, Based on Reason.” In this essay, he put forth what he called the “Principle of Sufficient Reason,” which says, in essence, that there is an explanation for every fact, an answer for every question. “This principle having been stated,” Leibniz wrote, “the first question which we have a right to ask will be, ‘Why is there something rather than nothing?’ ”
For Leibniz, the ostensible answer was easy. For reasons of career advancement, he had always pretended to hew to religious orthodoxy. The reason for the world’s existence, he accordingly claimed, was God, who created it through his own free choice, motivated by his infinite goodness.
But what was the explanation for God’s own existence? Leibniz had an answer to this question too. Unlike the universe, which exists contingently, God is a necessary being. He contains within Himself the reason for His own existence. His nonexistence is logically impossible.
Thus, no sooner was the question Why is there something rather than nothing? raised than it was dispatched. The universe exists because of God. And God exists because of God. The Godhead alone, Leibniz declared, can furnish the ultimate resolution to the mystery of existence.
But the Leibnizian resolution to the mystery of existence did not prevail for long. In the eighteenth century, both David Hume and Immanuel Kant—philosophers who were at loggerheads on most issues—attacked the notion of “necessary being” as an ontological cheat. There are, to be sure, entities whose existence is logically impossible—a square circle, for instance. But no entity’s existence, Hume and Kant agreed, is guaranteed as a matter of pure logic. “Whatever we can conceive as existent we can also conceive as non-existent,” Hume wrote. “There is no being, therefore, whose non-existence implies a contradiction”—including God.
But if God does not exist necessarily, then a wholly novel metaphysical possibility presents itself: the possibility of absolute nothingness—no world, no God, no anything. Oddly, however, neither Hume nor Kant took the question Why is there something rather than nothing? seriously. For Hume, any proposed answer to this question would be “mere sophistry and illusion,” since it could never be grounded in our experience. For Kant, attempting to explain the whole of being would perforce involve an illegitimate extension of the concepts that we use to structure the world of our experience—concepts like causality and time—to a reality transcending this world, the reality of “things in themselves.” The result, Kant held, could be only error and inconsistency.
Chastened, perhaps, by such Humean and Kantian strictures, subsequent philosophers largely shied away from confronting the question Why is there something rather than nothing? The great pessimist Schopenhauer, who declared the mystery of existence to be “the balance wheel which maintains in motion the watch of metaphysics,” nevertheless called those who pretended to resolve it “fools,” “vain boasters,” and “charlatans.” The German romantic Friedrich Schelling stated that “the main function of all philosophy is the solution of the problem of the existence of the world.” Yet Schelling soon decided that it was impossible to give a rational account of existence; the most we could say, he felt, was that the world arose out of the abyss of eternal nothingness by an incomprehensible leap. Hegel wrote a good deal of obscure prose about “the vanishing of being into nothing and the vanishing of nothing into being,” but his dialectical maneuvers were dismissed by the ironic Danish thinker Søren Kierkegaard as little better than “spice-seller’s explanations.”
The beginning of the twentieth century saw a modest revival