If the universe did have a beginning, it becomes not only reasonable but also unavoidable that we would ask what generated that beginning. Now, however, we have left physics (i.e., how nature works) for meta-physics (i.e., why nature exists at all).
This is the point at which a theist calls attention to a traditional and powerful argument for God's existence. If the material universe has not existed forever, the possibilities are limited. Either it somehow called itself into being or was brought into being by an eternal Creative God. From Plato to Polkinghorne, Aristotle to Aquinas, Darwin to Davies, this argument has been offered.
In his recently released book "The Grand Design," Stephen Hawking gives this answer:
As recent advances in cosmology suggest, the laws of gravity and quantum theory allow universes to appear spontaneously from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going.
We need not pretend that ultimate questions such as Hawking raises are too profound for "ordinary souls" to contemplate; they are central to defining oneself and deciding on the value and meaning of one's life. Neither should we pretend that statements such as "something can come from nothing" or "life arose spontaneously and inevitably produced intelligent human life" is somehow plausible because spoken by a brilliant physicist; both are undemonstrated theories that deny the more obvious and direct conclusion of a Grand Designer.
If there had ever been a time when absolutely nothing existed, nothing could exist now. Since something clearly has existed forever, you take your pick: Person or matter, Intelligence or gravity, Creative God or quantum mechanics.
To say the least, the following thesis is reasonable: "In the beginning, God created the heavens and the earth" (Genesis 1:1).