Cosmology deals with the origins and structure of the whole universe, and until quite recently it was inconceivable to do this without mentioning God. Newton, who spent a large part of his life working out Biblical chronologies, took it for granted that God must have organized the architecture of the Solar System; and Kant, in his remarkably far-sighted Universal Natural History and Theory of the Heavens
from 1755, also assigned God a major role. Nowadays, however, most scientists leave God out of the picture. But how did the changeover happen? In this impartial and thoroughly-researched book, Kragh gives you the details.
It's an interesting if sometimes rather bewildering story. By 1800, when Laplace was putting together his monumental book on celestial mechanics, astronomers were starting to think that God wasn't necessary, and Newtonian physics was all you needed. At least, this was Laplace's opinion, and as the leading theoretical astronomer of the time it carried a lot of weight; many scientists were convinced. But, as Kragh shows, there were things left to explain which Laplace hadn't considered. In 1850, Clausius formulated the Second Law of Thermodynamics, which states that the entropy of an isolated system always increases. People soon thought about applying the Second Law to the whole universe. If entropy increases over time, then, the further back you go in time, the lower it must have been. At some point, entropy must have been at its minimum possible value, and this would mark the beginning of the world.
But what happened before that? Quite a lot of scientists were now happy to put God back into the picture, while others criticized the argument from various points of view: a common claim was that it made no sense to talk about the entropy of the whole universe. Then, after Einstein came up with his theory of General Relativity in 1916, a new argument emerged. It soon became clear that it wasn't possible any more to have a static universe. More and more evidence emerged pointing towards the idea that the universe must have expanded from an initial singularity, which would again mark its beginning. Once more, there were scientists who interpreted this initial point as the moment where God created the universe, and there were others who questioned the validity of the concepts. Interestingly, one of the most important figures in the story was the Belgian scientist Georges Lemaître, who was also an ordained priest; but Lemaître was scrupulous about avoiding religious interpretations of something he saw as a purely scientific matter.
In both of these debates, I saw interesting parallels with A.D. White's History of the Warfare of Science with Theology in Christendom
, which I read a few weeks ago. White examines a number of cases where science has come into conflict with religion - evolution, demonic possession, witchcraft, etc - and in his book it's always the same pattern: religion says one thing, science says another, evidence emerges increasingly showing that science is right, religion gives up and seeks a compromise. But here, I thought it was more the opposite. Many scientists, as Kragh shows, were extremely reluctant to consider that the universe could have had a beginning. They offered all sorts of objections, some of them not very sensible. (My favorite comes from Zhdanov, director of cultural policy under Stalin: relativistic cosmology is bourgeois). But more and more evidence came in, and finally, around 1965, the scientific world capitulated and admitted that the Big Bang theory is correct, and the universe began 13.7 billion years ago. They immediately proceeded to make the idea their own, and now you have scientists like Krauss, in A Universe from Nothing
, who argue that the Big Bang proves God doesn't
As Kragh wearily says at the end: people should have more sense than to make claims like these, since a cursory study of the subject shows that theologians, since the days of Thomas Aquinas, have agreed that the question of whether the universe has a beginning is quite separate from that of whether it was created. But scientists evidently have better things to do with their time than study theology and metaphysics. He also says that, despite the acres of ink that have been spilled in the course of this debate, he has not come across one writer who has changed his position as a result of reasoned argument. As a conclusion, it's a little depressing. But the book is fascinating, and if you're at all interested in the relationship between science and faith I can't recommend it too highly. There is an online version available here