Quite commonly, religion and science are said to be somehow antagonistic, in opposition to one another. In reality, they have a great deal in common [1].
Both are human activities. Both are intellectual activities. Both have the aim of understanding the world and ourselves.
Religion and science differ mainly in the degree to which their knowledge-seeking relies on empiricism.
Science, of course, is often supposed to be a bottom-up, fundamentally empirical search for truth. In practice, however, some things in science have come to be so widely believed that they function as dogmas — even when the “bottom-up” evidence does not prove the dogmatic belief to be correct [2].
Religion, on the other hand, is often supposed to be a purely a matter of blind faith. In fact, however, there is inevitably empirical reliance on, for instance, the choice of which scriptures or whose interpretations or whose revelations to take as authentic. That is illustrated clearly enough in the existing profusion of different religions and sub-divisions of religions, sects, cults.
Above all, the fact that both religion and science are human activities means that they both display all the human qualities: honesty and dishonesty, greed and selflessness, open-mindedness and dogmatism, etc.
Moreover, since both religion and science have developed a profusion of institutions and associations, both display the characteristic problems and deficiencies of human institutions: the tension between autocratic control and democratic governance; the problems of interacting with other human institutions; the wish for institutional advancement, for institutional power; “outreach” efforts and initiatives to be respected or admired or imitated by the rest of humankind — propaganda; charitable work, missionary work by religions, establishment of global institutions in science.
The notion that religion and science are in constant opposition may be the consequence of the mid-19th-century publication by Darwin of the theory that humans evolved from animal ancestry.
But neither religion nor science is able to provide humanly meaningful explanations for the fundamental mystery of existence: Has the world and universe of which we are aware always existed, or was there a finite beginning?
Human comprehension is simply inadequate for understanding that issue [3]. God-based religions cannot explain where God came from; and the currently popular “scientific” “Big-Bang” theory is equally unable to explain what it was that “Banged”. (A substantial minority of astronomers and astrophysicists still prefer the “steady-state” theory [4].)
It seems reasonable to conclude that we can never come to know or understand matters outside what we can experience directly — things that are familiarly at human scale, for example in size.
So we should beware of proposals or actions that claim to be based on some absolute truth and that fail to take account of human nature and fallibility.
That's why, for example (paraphrasing George Santayana), we need to know and understand as much as possible about history, in order not to repeat what we would rather not have happened.
It would also be good to bear in mind (paraphrasing Shakespeare) that the evil men do lives after them, and to educate our children In that light. It seems to me a bad idea of some religious sects, to believe that personal sins or guilt can be erased afterwards by some sort of confession or act of faith: better to bear in mind that bad things once done cannot be undone, because their consequences have already affected others.
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[1] Which explains how first-rate scientists may also be quite orthodox Christians, for instance. Moreover, clerics were prominent among those pre-scientist “natural philosophers” who founded “modern” science in the 15/16th centuries in the West
[2] As with 20th-century eugenics, and contemporary HIV/AIDS; CO2-caused climate-change; cholesterol as cause of cardiovascular disease; blood-pressure guidelines ignoring age; and more; see my Dogmatism in Science and Medicine: How dominant theories monopolize research and stifle the search for truth, McFarland, 2012
[3] On this assertion, read Fred Hoyle’s sci-fi master-work, The Black Cloud
[4] A useful discussion is at https://arxiv.org/pdf/1506.01651
God does not come from anywhere. God is Being itself and the source of all other existence. This is a philosophical rather than a strictly religious position, although the implication is that there is only one God, since ultimate Being implies monotheism.