Science puts out theories based on what the evidence says. As new evidence may come in, it is ready to look again and improve and revise. Bad theories are valued, only showing us how to learn from mistakes. A theory that avoids evidence entirely or tries to make out that feelings and notions and hearsay count as evidence is classed as "not even wrong" in science. In other words, it is worse than one that gets the evidence wrong. God is in that category.
Science is about being open to abandoning its ideas if they are shown wrong. Religion says God tells it its ideas are true. It adds that trust requires that you believe God's testimony — even if evidence comes up that it is wrong. While many faiths do claim to respect evidence, they differ on how much evidence matters and why. They all agree that if science started saying God was fiction, they should keep believing.
It is clear that religion is a threat to truth and science is not. Religion makes a sideshow to distract from that by saying science has its sphere and business and religion has a different one, so one cannot really refute the other.
Religion calls evil a malfunction. It means it is not a real substance — but is just good failing to reach its potential. Science, however, will not in principle or practice take that for granted. In theory, it could test evil and declare it a real substance. That is one example of how science and religion, in principle, are opposed.
Science is the study of what functions and what does not. Normal is important to it. That is how theories come about. So religion cannot say science is about the physical — not the moral or the spiritual. It may be an indirect but real relationship. Religion says there is no evil unless there is a God. It will not agree sufficiently with science on what normality is, for science ignores both its God and its account of evil. It is not true that science, which is heavily concerned about the normal, is outside the realm of religion.
Science hopes its laws and the laws of nature match up — that science is truly descriptive. Laws of nature are also laws of science, in principle. It takes work to make sure you have got it right. When there is no match, all that is wrong is that there is science to be discovered. Science is not about just what we have but about what is out there and that is waiting to be found.
Reason is science. Science is reason. Reason is basically if A, then not B. Science does everything with that principle. Just seeing that your tea is cold, not hot, is science. Your body is the machine you do the experiment with. The computer in your head is what is assessing and interpreting and understanding the experiment. Science at its core goes back to all that. Science is about what can be tested to see if it is there. Then it thinks about it. So reason is based on natural things. Metaphysical reasoning is not reasoning at all. There is no test to see if a being without parts or material components or a body can exist. Thus, science and supernatural claims are in conflict. Notice I said supernatural claims. That is not the same thing as saying science and the supernatural cannot agree. It is the same thing as saying that the problem with the supernatural is not the supernatural but the claims made about it.
Science — whether secular or coming from Christians — has destroyed many religions. It has shown that you cannot control how the sun rises by offering human sacrifices. It shows that there are no gods living on Mount Olympus. Most religions have been exposed by science. Some go a step further and argue that science debunks, at least implicitly, the religions of Christianity and Islam.
Religion cares about what you believe and what you think and not how you think. That is what religion is for. Some religions try to brainwash, while others try to draw you in by being nice to you.
Science does not care in the slightest what you believe or want to believe. It is ruthless regarding truth and finding it. Even scientists who assert something in the name of science cannot appeal to their own authority — they have to present the case for what they say and are subject to ruthless examination.
Scientists and theologians who say religion and science fit are
wrong and, thankfully, small in numbers. Both the scientists and the
theologians are probably just Trojan Horse people who want to wear
down the other side gradually while pretending to respect it.
Science is not based on proof by experiment. It is proof. The
experiment is only necessary to show that it is proof. It is thought
that science has nothing to say about religious faith, for it is
verified or shown probably true by ways and means other than
science. But the reality is that science only regards testable stuff
as possibly true, and the testing is done by experimentation and
reasoning to see how a discovery fits other discoveries. Religion
never experiments in any form. Science upholds all experimentation,
even if it is testing nonsense, and regards anything that does not
experiment as not only non-scientific but anti-scientific. Even bad
experimentation methods are better than nothing in the estimation of
science. There is nothing worse than something that is put outside
the realm of testing. Science rejects whatever is unconcerned about
experimentation 100%.
Science depends on the tacit working assumption that the supernatural does not happen. The supernatural does not help science understand the universe, so science sees itself as mattering and religion as not mattering. It is that simple. But many ignore it and obscure and confuse.
The other matter is that not a single religion gets the official support of science — not even as being the one religion that is more scientifically supported and respectful to science than the others. Science does not say any religion has got it reasonably right in terms of science. Religion will hijack science for its own ideological purposes - it never lets science ratify.
In short, science and religion fundamentally exclude each other. Science relies on evidence, testing, and reason, constantly revising its ideas, while religion depends on faith and untestable claims that resist evidence. Their core methods and goals conflict, making true reconciliation impossible. Science seeks truth through proof; religion relies on belief without proof. Religion also lies that it does not encroach on scientific territory. It does.