I should mention first that this is a loaded question, with several hidden implications. A "purpose" presupposes a mind that conceived it, as well as the ability to implement it. In the present case, this means that the owner of the mind not only created the universe the way it is, but could have created another universe and decided to create the existing one for a specific reason. So the question really deals with the belief in a Creator who enjoys almost infinite power and freedom but, at the same time, goes through the very human process of pondering decisions and acting accordingly. In a way, this is a very anthropomorphic vision of God.

A second aspect of the question concerns the motivation behind the purpose. What did God have in mind in creating the universe the way it is? Being the ones who ask the question, it is obvious that we see ourselves as at least part of God's goal. As pointed out by the defenders of the "anthropic principle," what is peculiar about the universe is that it happens to have just the right physical properties to give rise to life and, through life, to human minds. Such an anthropocentric view of the creation is, however, not readily reconciled with what is known of the evolutionary origin of humankind.

Personally, I do not accept the implications of the term "purpose." Sticking to the facts, I prefer the undisputable statement that the universe happens to be such that certain events, including the generation of life and mind, were possible, perhaps even probable, if not obligatory. Instead of searching the "mind of God" for the explanation of this fact, I see it as an expression of reality and as a significant clue to the nature of this reality.

Many scientists and philosophers have taken this attitude. The late French biologist Jacques Monod, for example, concluded in 1970, after reviewing the great discoveries of his days, that the universe is a meaningless entity in which life and mind arose by an extraordinary combination of improbable circumstances and could very well never have arisen at all. As he claimed, "the universe was not pregnant with life, nor the biosphere with man," leading to the stoically despairing conclusion that "man knows at last that he is alone in the unfeeling immensity of the universe out of which he arose only by chance." Many biologists of Monod's generation have shared this opinion, spreading what I have called the "gospel of contingency."

Since then, the message of science has changed. Most biologists, today, tend to see life and mind as cosmic imperatives, written into the very fabric of the universe, rather than as extraordinarily improbable products of chance. But the philosophical content of Monod's view has survived in the so-called "multiverse" theory. According to this theory, advocated, among others, by the British astronomer Martin Rees and by the American physicist Steven Weinberg, and now much popularized by the media, our universe is but one among a multitude of others that do not share its properties, the only one that happens by chance to have physical constants such that it could naturally evolve to give rise to life, which, itself, naturally evolved to give rise to mind. Because of the need for a mind to be aware of such a universe, it is, by necessity, the only one in the multiverse capable of being known, at least by entities of its own making. Except for that, there is nothing special about it. We are back in Monod's "unfeeling immensity out which we arose only by chance." The difference is that it is not we who arose by chance in the universe, but rather the universe (in which we were bound to arise) that arose by chance in the multiverse.

For reasons that I have explained elsewhere, I do not subscribe to this view. In my opinion, life and mind are such extraordinary manifestations of matter that they remain meaningful, however many universes unable to give rise to them exist or are possible. Diluting our universe with trillions of others in no way diminishes the significance of its unique properties, which I see as revealing clues to the "Ultimate Reality" that lies behind them.

Science has given us a glimpse of this reality, by revealing the strange objects and concepts, almost irreducible to our familiar world, that lie behind entities such as the cosmos, matter, life, and mind. Through music, art, and literature, we have been allowed to approach another facet of this reality, emotional and esthetic, rather than intelligible. With philosophy and religion, we have become aware of its ethical and mystical aspects. Encompassing all in a single manifestation, love has introduced us into its very heart.

It will be noted that there is no logical need for a creator in this view. By definition, a creator must himself be uncreated, unless he is part of an endless, Russian-doll succession of creators within creators. But then, why start the succession at all? Why not have the universe itself uncreated, an actual manifestation of Ultimate Reality, rather than the work of an uncreated creator? The question is worth asking.

Bibliography
Christian de Duve. Vital Dust: Life as a Cosmic Imperative. New York: BasicBooks (1995).
Christian de Duve. Life Evolving: Molecules, Mind, and Meaning. New York: Oxford University Press (2002).
Jacques Monod. Chance and Necessity. Translated from the French by A. Wainhouse. New York: Knopf (1971).
Martin Rees. Before the Beginning. Reading MA: Perseus Books (1998).
Steven Weinberg. Facing up. Cambridge MA: Harvard University Press (2001).