"It doesn't matter how unlikely the universe is, God is more unlikely." - a paraphrase of Richard Dawkins's "central argument" in The God Delusion.This idea focuses on the fine-tuning argument, which essentially says the universe appears highly finely-tuned for the existence of advanced life. This observation is a relatively non-controversial statement based on scientific evidence. Atheist Richard Dawkins, in The God Delusion, admits the statistical improbability of the universe, but he dismisses this as a case for God by saying that God is even more improbable. But this just reflects his own presuppositions about the probability that God exists, and does not rest on any real evidence. And the problem with making such a presumptive dismissal is that if you continue to hold this position as the evidence for the fine-tuning gets stronger (which it does every day), then you are in essence saying that the probability God exists is smaller than any small number you can come up with. In other words, you are assuming from the beginning that the probability that God exists is zero.
This is circular reasoning of the worst kind, and amounts to the atheistic version of blind faith. If you start off by assuming that God cannot exist1, then no amount of evidence, no matter how strong, can budge you. Dawkins is essentially saying, "I don't care what the scientific evidence for fine tuning says, I will choose to believe that God does not exist." That is not reason or rationality, that is blind belief. Belief, as it were, in spite of the evidence.
1Note: I'm not saying does not exist; I'm saying cannot.