Really?
That seems like total bollocks to me. I mean, we don't approve of slavery any more do we?
Well, hopefully most of us don't. And it's worth noting that little of modern attitudes to the phenomenon have much to do with science (or in fact, 'enlightenment' thought - I've just noticed that Hume and Kant were thoroughly racist). It should be noted how close we are in time to attitudes which only lie a bus-ticket's width away from leading to slavery. Insofar as a whole host of scientific thinkers right up to modern times were completely racist (with H.G. Wells, the Webbs and Shaw throwing Eugenics into the mixture). I was surprised to learn that Julian Huxley belonged to this brigade - here he is in 1931:
"There is a certain amount of evidence that the Negro is an earlier product of human evolution than the Mongolian or the European, and as such might be expected to have advanced less, both in body and mind".
He kept quiet on such matters from the mid 30s (I wonder why?). Not that he had any further scientific data to change his mind, but he soon saw the horrors that such an attitude to race might bring. In fact we didn't get any real data to refute such views until Crick and Watson, and even then genetic studies had to wait some time to prove that there was no uniform racial difference in the peoples of Africa from the rest of the world. Genetic research has now revealed that there is far more genetic diversity among the African peoples than all the rest of the people on the planet.
So far so good, science does seem to advance knowledge positively, but perhaps not quite so objectively as we might like. There's much trumpeting of the 'scientific method' and the 'principle of falsification' - but don't those date merely date back to Karl Popper? Arthur Koestler in his book 'The Sleepwalkers' seems to indicate that scientific discoveries for a long time didn't proceed in any such manner.
I'm with Dawkins and other militant atheists in their opposition to various forms of religious fundamentalism (so as a matter of fact is John Gray), but denigrating all religion in favour of 'science' seems to be a huge miscalculation. Religion keeps springing up everywhere, and the attitude of western atheist liberal thinkers is not likely to have much effect on these matters. Let's not have any truck with the 'God of the gaps', though.
Worst of all, (something I haven't time to go into here) is the idea beloved of some western politicians that we can impose liberal democracy onto societies which have had no such tradition of thought as the west. Whenever this has been tried, it's been a disaster. The Islamic world, in particular, has had no period of critique of religion, no 'Enlightenment' period, and to try to graft alien western ideas on to these societies seems doomed to failure.