But if the direct conflict between scientific knowledge and specific religious beliefs has not been so important in itself, there are at least four sources of tension between science and religion that have been important.
The first source of tension arises from the fact that religion originally gained much of its strength from the observation of mysterious phenomena – thunder, earthquakes, disease – that seemed to require the intervention of some divine being. There was a nymph in every brook, and a dryad in every tree. But as time passed more and more of these mysteries have been explained in purely natural ways. Explaining this or that about the natural world does not of course rule out religious belief. But if people believe in God because no other explanation seems possible for a whole host of mysteries, and then over the years these mysteries were one by one resolved naturalistically, then a certain weakening of belief can be expected.
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Of course, not everything has been explained, nor will it ever be. The important thing is that we have not observed anything that seems to require supernatural intervention for its explanation. There are some today who cling to the remaining gaps in our understanding (such as our ignorance about the origin of life) as evidence for God. But as time passes and more and more of these gaps are filled in, their position gives an impression of people desperately holding on to outmoded opinions.
The problem for religious belief is not just that science has explained a lot of odds and ends about the world. There is a second source of tension: that these explanations have cast increasing doubt on the special role of man, as an actor created by God to play a starring part in a great cosmic drama of sin and salvation. We have had to accept that our home, the earth, is just another planet circling the sun; our sun is just one of a hundred billion stars in a galaxy that is just one of billions of visible galaxies; and it may be that the whole expanding cloud of galaxies is just a small part of a much larger multiverse, most of whose parts are utterly inhospitable to life. As Richard Feynman has said, “The theory that it’s all arranged as a stage for God to watch man’s struggle for good and evil seems inadequate.”
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A third source of tension between science and religious belief has been more important in Islam than in Christianity. Around 1100, the Sufi philosopher Abu Hamid al-Ghazzali argued against the very idea of laws of nature, on the grounds that any such law would put God’s hands in chains. According to al-Ghazzali, a piece of cotton placed in a flame does not darken and smolder because of the heat of the flame, but because God wants it to darken and smolder. Laws of nature could have been reconciled with Islam, as a summary of what God usually wants to happen, but al-Ghazzali did not take that path.
Al-Ghazzali is often described as the most influential Islamic philosopher. I wish I knew enough to judge how great was the impact on Islam of his rejection of science. At any rate, science in Muslim countries, which had led the world in the ninth and tenth centuries, went into a decline in the century or two after al-Ghazzali. As a portent of this decline, in 1194 the Ulama of Córdoba burned all scientific and medical texts.
Nor has science revived in the Islamic world. … in 2002 the periodical Nature carried out a survey of science in Islamic countries, and found just three areas in which the Islamic world produced excellent science, all three directed toward applications rather than basic science. They were desalination, falconry, and camel breeding.
Something like al-Ghazzali’s concern for God’s freedom surfaced for a while in Christian Europe, but with very different results. In Paris and Canterbury in the thirteenth century there was a wave of condemnations of those teachings of Aristotle that seemed to limit the freedom of God to do things like create a vacuum or make several worlds or move the heavens in straight lines. The influence of Thomas Aquinas and Albertus Magnus saved the philosophy of Aristotle for Europe, and with it the idea of laws of nature. But although Aristotle was no longer condemned, his authority had been questioned – which was fortunate, since nothing could be built on his physics. Perhaps it was the weakening of Aristotle’s authority by reactionary churchmen that opened the door to the first small steps toward finding the true laws of nature at Paris and Lisieux and Oxford in the fourteenth century.
There is a fourth source of tension between science and religion that may be the most important of all. Traditional religions generally rely on authority, whether the authority is an infallible leader, such as a prophet or a pope or an imam, or a body of sacred writings, a Bible or a Koran. …
Of course, scientists rely on authorities, but of a very different sort. If I want to understand some fine point about the general theory of relativity, I might look up a recent paper by an expert in the field. But I would know that the expert might be wrong. One thing I probably would not do is to look up the original papers of Einstein, because today any good graduate student understands general relativity better than Einstein did. We progress. Indeed, in the form in which Einstein described his theory it is today generally regarded as only what is known in the trade as an effective field theory; that is, it is an approximation, valid for the large scales of distance for which it has been tested, but not under very cramped conditions, as in the early big bang.
We have our heroes in science, like Einstein, who was certainly the greatest physicist of the past century, but for us they are not infallible prophets.