Big Bang =/= Creation!
Both PZ and Amanda point out the double standard that Collins uses: against both creationists and atheists like Richard Dawkins he says that science can never disprove the existence of a trascendent God that does not intervene in the Universe but created it entirely, so science and evolution are compatible with belief in God (something I have argued for extensively) but next he contradicts his premise in two different ways: first he tries to argue for the existence of God from scientific facts such as the Big Bang, and second he states his belief in miracles such as the Virgin Birth and the Resurrection. The first involves a double standard in that if Collins can take God as a scientific hypothesis to explain particular aspects of the universe, then Dawkins and other atheists are allowed to do the same, and by all scientific standards the God hypothesis comes out as a terrible one, untestable and explaining everything and nothing. That is why I think fideism is practically the only consistent position for a religious scientist. The second involves a double standard in that Collins has (rightly) ruled out miraculous divine intervention as a viable explanation in biology, but now allows it in matters of Biblical history just because he regards them as more central to his faith. If biologists studying evolution must rely on methodological naturalism and reject divine intervention as explanation for biological facts, then Bible scholars and historians studying the life of Jesus must also rely on methodological naturalism and reject claims of miracles. Fair is fair.
I want signal out for criticism the way Collins uses the Big Bang in support of theism, first because neither PZ nor Amanda deal with it, and second because it will allow me to clear several misconceptions the general public has about the theory. Collins says:
First of all, we have this very solid conclusion that the universe had an origin, the Big Bang. Fifteen billion years ago, the universe began with an unimaginably bright flash of energy from an infinitesimally small point. That implies that before that, there was nothing. I can't imagine how nature, in this case the universe, could have created itself. And the very fact that the universe had a beginning implies that someone was able to begin it. And it seems to me that had to be outside of nature. And that sounds like God.
The Big Bang is most definitely not an unimaginably bright flash of energy from an infinitesimally small point. As remarked by the Angry Astronomer in his much-linked to post on a similar topic, it is more like an expansion that an explosion. The universe is spatially infinite according to the standard contemporary theory, so it did not start form one very small point and expand from it. Instead, it started from one very dense state, and it became less dense by space itself expanding, not by matter spreading apart. The best analogy I know of is an infinite chessboard, in which the size of the squares doubles at a fixed rate. Then, imagining a particle of matter at the centre of each square, all the particles are moving away from each other and each one sees all the others moving away from itself. In the past particles were much densely packed together, but the universe itself was always infinite, not smaller -though any specific finite region within the universe was indeed smaller in the past, and started off from a point, at least in this idealized model.
This, however, is a side issue of little relevance for the religious argument. (Of even less relevance, though I still can't resist remarking it, is that radiation "decoupled" from matter only 300,000 years after the Big Bang, so there was no "free" light around in the primordial universe. So much for "Let light be made"!) The main point I want to make is that the Big Bang cannot be identified with Creation, and that the Big Bang theory does not give any special support to the notion of divine creation (although it does not contradict it).
First, from the philosophical point of view, since God is supposed to be outside time, I can't see why a universe that has started in time squares better with a Creator than a universe that has existed forever. An eternal and omnipotent God could surely have created a universe with an infinite time span as easily as one with a finite one. But of course what those who equate the Big Bang with Creation are looking for is not any Creation but one that resembles, even in the most vague possible way, the narration of Genesis. Well, let's move on.
The second and main point is that even though the model we use for the present universe, extrapolated backwards, does lead to a "t=0" instant where the universre started, we know that the model cannot be trusted for very early times. When the density of matter becomes so large as to approach the so-called Planck density (more than 10^96 kilograms per cube meter!) then our present theories cannot make reliable predictions anymore, and some yet-undeveloped theory of quantum gravity would be necessary. We do not know what such theory would imply for times earlier than those we can reach through our present theories. It might be that the universe was more or less stationary in such a dense state until a random quantum fluctuation provoked an expansion. Or it might be that a previous large universe collapsed to the Plack density and then "bounced", as some (preliminary!) results in the "Loop Quantum Cosmology" approach suggest. The only thing most physicists agree on is that physics does not "end" at the Big Bang, as in the naive model many people have and imagine that fits well with their religion. Beyond the Big Bang, or rather, beyond the Planck density scale (as there is no real event we can call the Big Bang, aside form the general fact of a very dense past) there is not God but just presently unknown physics.
An analogy: imagine a cannonball being fired; after it leaves the cannon, it is in a fixed parabolic trajectory (neglecting friction). Intelligent ants that appeared in the ball a while after it left the cannon could calculate the parabolic trajectory, and conclude that the cannonball had been touching the ground a definite and calculable time ago. However, this would be a wrong conclusion; in the first moments of the trajectory, the ball was inside the cannon, constrained by it to move in a straight line, and being moved not only by gravity and inertia but also by the pressure of the exploding gases. Different physics took over in the first instants, in other word, though the simple physics of parabolic motion is a correct and excellent description for the part of the motion the ants have experienced. If for a philosophical ant it is a matter of great importance whether the ball has ever been in touch with the ground, however, it should refrain to conclude that it had just because the parabolic motion leads to that inference. It should study the physics of cannons to discover what the ball had been doing at times when the simple theory breaks down. And it would discover the the ball was initially not in touch with the ground, but with the bottom of the cannon's inside.
Using the Big Bang to argue for God, is, in effect, a straightforward example of the God of the Gaps fallacy. It is not recognising our present knowledge to be limited and expandable with hard work, and lazily calling up God to replace the part we don't yet understand. It is a testimony to the power of belief to overcome reason that Collins, who evidently recognizes the fallacy when IDers apply it in his area of expertise, applies is so carelessly himself in a different area.