There’s been a lot of public discussion about the conflict between science and religion, whether there is one, and what it consists of. I think it might be worth looking at this in some detail.
First of all, I’d like to describe a bit about science, what it is and how it works. The press tends to report science much as it does politics - looking for disagreements and arguments between authority figures who can be persuaded to say uncomplimentary things about each other, and each of whom will defend their view in order to persuade others. The problem is that science isn’t actually like that.
Scientific theories are descriptions of the way the world works. You start with observations. Let’s take a very simple example. You notice that when you throw a stick up in the air, it falls to the ground again. No matter how many times you throw it up, it always seems to come down again. So you generalise this into a theory.
What goes up, must come down.
Although it is expressed in a very primitive fashion, this is in fact a respectably formed scientific theory. Other people can also throw sticks in the air and see if they come down for them. They can also try with other objects, such as stones. If they all come down, that is said to confirm the theory. If any of them don’t, it disproves it.
Now, suppose on some occasion, you throw a stick up and you don’t see it come down. Must the theory be changed? Not necessarily. There are various possibilities that you have to eliminate first. The most obvious one is that you lost sight of the stick and didn’t see it land. Or perhaps it got stuck up a tree. These sorts of problems are what scientists call measurement error, and it happens frequently, in fact far more often than truly new results that disprove existing theories.
Once you have established that your theory is probably correct by throwing lots of sticks, stones and other objects up in the air and seeing that they do come down, you can try to refine it. For instance, you can ask how fast do things come down? So you vary the experiment, you throw things up with different amounts of force, and measure how high they get and how long it takes for them to return to the ground. After doing this enough times, you are able to work out that the acceleration is constant, and is about 9.8 meters per second squared. In other words, every second, the downward speed of the falling object increases by 9.8 meters per second. This means that for instance if you know the speed with which a cannonball comes out of a cannon, and you know the upward angle at which it is fired, you can predict pretty closely where it will land. That is quite a useful thing to know in battles. And as it happens, Galileo, who famously dropped two different-sized lead weights off the top of the Leaning Tower of Pisa in order to demonstrate constant acceleration, wrote artillery manuals that would predict the fall of shot in this way.
But very light objects don’t seem to behave the same way. Balloons and feathers fall far more slowly. What of them? The number is no use if you can’t tell what objects it applies to and what objects it doesn’t. And so you have to start taking into account air resistance, and work out how much that affects the figures. And so on.
This is a very simple example, but it describes exactly what science is about. You make observations, and get your theories to fit them. And if you then get observations which aren’t predicted by the theories, once you have eliminated the possibility of measurement error, you have to change the theory.
That is why, whenever an experiment is reported in a reputable peer-reviewed scientific journal, there is a very specific format that has come to be used. First you describe what the experiment was intended to test. Then you describe your methods, how you went about testing it. Then you describe your results, and finally you offer any hypotheses that you think could be generalised from the results.
This separation has a very particular purpose. No scientist expects his word to be taken on its own authority. Scientific papers are written specifically so that others can repeat the experiment and see whether they get the same results. They can also look at the methods and may point out some measurement error that the original scientist didn’t think of. Or somebody might think of an alternative theory that explains why the results are the way they are. The scientist writes everything down that he or she can think of that might mean the experiment is wrong. Scientists are of course human, and don’t always manage to meet this high ideal. But this is what they aim for.
Now where does the conflict with religion come in? First let’s explain what the conflict is not. This is not about hordes of atheist scientists who have discovered evolution as the new religion, appointed Darwin as their prophet, chosen The Origin Of Species as their sacred text, and have declared war on all competing religions. That is the old religious way of thinking, and if you have understood anything at all of what I have written above, you will realise that scientists don’t think that way.
In practice there are two parts to the conflict. First is the business of always starting from observation. If you have no observations, you have nothing to make a theory about. As a result of scientific discovery we have learned that many things previously thought to be the work of God intervening in the world to enforce his sense of morality are in fact the result of natural processes. We have learned that many diseases are caused by germs, and that antibiotics work to cure them irrespective of whether the person being cured is a sinner or righteous. We know the cause of lightning, and that a lightning conductor works just as well on the roof of a brothel as on the spire of a church. These answers seem to conflict with what religion has told us.
The thing is, in all these observations and discoveries, we do seem to be a bit short of actual sightings of God. That means that science can’t really offer any theories about God, because we have no observations on which to base theories. Every time a scientific discovery has been made in an area previously thought to be evidence of God working in the world, it has turned out that the phenomenon can actually be explained by the consistent operation of unchanging natural laws. There hasn't been a single case where the scientists have concluded "Oh, it turns out that this is God working in the world after all".
The other part of the conflict is the question of testing and cross-checking. Scientists are trained not to accept each other’s authority. They want to check the evidence by trying things out for themselves and seeing if they get the same results as each other. This can get very complicated. For instance, human beings are very complex and varied, and don’t always react in the same way to things, and so your results have to take this variability into account if you are testing things like whether particular drugs work to cure a disease. Almost all the complexity of modern experimental science is in trying to get rid of measurement error and cope with this sort of variability, so we can be sure that we really know what we think we know.
Religion works in a somewhat different way. The most important is that you are not supposed to check things, you are supposed to accept them as a matter of faith, and that holding fast to this faith is regarded as a good thing of and for itself. Several passages in the Bible say words to the effect of “Do not put the Lord your God to the test”. This is absolutely the complete opposite of the way scientists think.
Some religious people, seeing that scientists have gained a lot of prestige in terms of having their explanations of the world accepted by the public, have decided that they ought to try offering what they think of as scientific evidence in support of biblical stories. Unfortunately, again they are thinking in the opposite way from the way real scientists think. They start with a Biblical story (e.g. of Noah's Ark) and develop a theory from it (e.g. that there was a worldwide flood). Then they look around for evidence that supports the theory and carefully ignore anything that offers an alternative explanation. So long as they use lots of long sciencey-sounding words and write papers with lots of impressive-looking footnotes, they can fool quite a few non-scientists into thinking that they are doing real science. But it isn’t so. Real scientists start with observations before forming a theory, and if some observations don’t match the theory, they don’t cherry-pick the ones that fit and ignore the rest. As a scientist you have to deal with the inconvenient observations as well as the ones which gave you the result you expected.
The conflict gets at its sharpest when considering what should be included when teaching science to children. Scientists, not unreasonably, want science lessons to be about the finding-out process of real science. Some religious people want the pseudoscience that is designed to support their religion included instead, and for this to be accepted on authority.
The crux of the conflict between science and religion is the conflict between evidence and authority.