For all his fervent enthusiasm for science, Dawkins shows very little interest in asking what scientific knowledge is or how it comes to be possible. There are many philosophies of science. Among them is empiricism, which maintains that scientific knowledge extends only so far as observation and experiment can reach; realism, which holds that science can give an account of parts of the world that can never be observed; irrealism, according to which there is no one truth of things to which scientific theories approximate; and pragmatism, which views science theories as useful tools for organizing and controlling experience. If he is aware of these divergent philosophies, Dawkins never discusses them. His attitude to science is that of a practitioner who does not need to bother with philosophical questions.
It is worth noting, therefore, that it is not as a practicing scientist that Dawkins has produced his assaults against religion. As he makes clear in this memoir, he gave up active research in the 1970s when he left his crickets behind and began to write The Selfish Gene. Ever since, he has written as an ideologue of scientism, the positivistic creed according to which science is the only source of knowledge and the key to human liberation. He writes well—fluently, vividly, and at times with considerable power. But the ideas and the arguments that he presents are in no sense novel or original, and he seems unaware of the critiques of positivism that appeared in its Victorian heyday.
more here.