Certainty is a feeling, an emotion. Reason, on the other hand, gives rise to doubts and uncertainties.
Science is rational, and exactly for that reason it is uncertain, which is what many people fail to appreciate. A widespread myth is that reason brings about - and knowledge means - certainty.
This is what causes all the confusions of the kind that surrounded vaccines and autism in Britain a few years ago, for example, and the general confusions about probability and risk: what causes them is the fact that people expect certainties from science. Instead, in reality science is made up of theories and hypotheses, which may be refuted now, or temporarily confirmed until they are refuted and replaced by a better theory later. That's how science progresses.
Reason can be used to arrive at certainties, but not at pieces of knowledge. This is the case when reason is used in logic, but only because in logical deductions we never arrive at new knowledge.
It is certain that, in a logical deduction, if the premise is true the conclusion is always true, but only because the conclusion does not say anything which was not already contained in the premise. A very simple example is: "If A and B are both true, then A is true".
The logical conclusion makes what was already contained in the premise explicit, that's why, if the latter is true (or better, well founded), so is the former. But this process does not originate new knowledge. It is a process of transformation of one statement into another, not of discovery.
This is why non-philosopher atheists like Richard Dawkins generate confusion among their followers: because they themselves are confused in the first place.
To identify science with rationality, although correct - even if we must add that science is only one among the various rational activities of the human intellect, not the only one as Dawkins et al seem to believe, and a religion like Christianity, for example, is another -, condemns science to perpetual uncertainty.
Furthermore, science does not establish the limits of rationality, but only those of possibility. In other words, what science does is to say: "This is not possible because it goes against the laws of nature". But it doesn't tell you, within the multiple, mutually-contradicting possibilities, which is the true one.
It must remain understood, however, that the best scientific theory we have could be wrong and one day refuted.
But even presuming that it won't be, science - both as a whole and as single scientific theories - rules out, as I was saying, physical (or empirical) impossibilities, namely the phenomena that go counter to the laws of nature (i.e. the laws of science), but among the various remaining possibilities cannot tell you which is the true one.
That's why saying that science has eliminated God (a creator of everything) is absurd. For as long as a creator of everything remains compatible with the laws of nature, as it has always been and it is even more now that the Big Bang theory presumes a period preceding the birth of the universe in which laws of nature did not exist, the hypothesis of God as creator is a possibility. Science can ony tell you that it is possible, and not if it's true or not.
Atheists, and not only the people that Dawkins managed to mesmerise but the British zoologist himself, don't seem to properly grasp what they are saying. And I'm not referring to God or religion, but to science: they misunderstand science itself.
I am willing to admit that Dawkins is aware of many of the things I said, that's why he always uses qualifiers like "almost certainly" or "probably" when he says that God doesn't exist or that science leads to that denial. However, he doesn't act or write as if he had any doubts at all. And, as I said at the beginning, certainty is an emotional state, not the product of rational thought.
Who knows, maybe science, born out of Christianity, with the first scientists wishing to understand God's work - the creation - through it, after a period in which it's been dominated by naturalism (only nature exists) aka materialism (only matter exists), will turn out to be just the way in which in the end humanity arrives at God, which was science founders' original intention.
Photo "Sunset" courtesy of the website Human Health and Animal Ethics