Science is almost totally incompatible with religion. I say "almost," but I do not wish that weasel word to be construed as weakness. The only point of compatibility is that there are well-meaning, honest people on both sides who are genuinely and deeply concerned with discovering the truth about this wonderful world. That having been said, there is no actual compatibility between science and religion.
Science's dispassionate stare examines issues publicly, exchanges information openly, discusses awkward points objectively, and builds up a network of interdependent ideas and theories that progressively expose the complex as an outcome of the simple. Religion's inwardly directed sentimental glow reflects on issues privately, exchanges information by assurance and assertion, discusses awkward points by warfare, terror, and coercion, and builds up a network of conflicting ideas that conceal ignorance under a cloak of high-flown yet empty prose.
Science reveals where religion conceals. Where religion purports to explain, it actually resorts to tautology. To assert that "God did it" is no more than an admission of ignorance dressed deceitfully as an explanation. Science, with its publicly accessible corpus of information and its open, scrutable arguments, can lead the wondering to an understanding of the entire physical world. (Below, of course, I shall have to argue that that is the entire world.)
Science respects the power of the human intellect; religion belittles it. Science gives us the prospect of full understanding, for it continues to show that, given time, there is no aspect of the world that is closed to its scrutiny and explanation. Religion disarmingly avers that human brains are too puny to achieve full comprehension. Yet science is progressively advancing toward complete knowledge, leaving religions bobbing about in its wake.
Science is hard work, but the answers it hews from the rock face of ignorance are reliable. Religion is armchair speculation well fitted to adipose brains. Science cannot answer deep questions by words alone: it draws on the perspiration of countless experimenters and the struggles of theoreticians to make sense of the data. Religion can speculate wildly, and therefore uselessly, from flabby, personal opinion and never be put to the test, except perhaps beyond the grave. There is, of course, no beyond the grave except in the minds of those who cannot come to terms with the prospect of their own annihilation.
Science searches for the underlying simplicity from which springs the astounding complexity that surrounds and delights us. Science is quarrying observations and seeking the ultimate simplicity of existence. Ultimate truth will be of awesome simplicity; tracing that simplicity up into the world of phenomena may well prove to be more demanding than the exposure of the simplicity. But that difficulty will not mean that the discovery of the simplicity is a false foundation. Religion searches for the all-embracing complexity — God — that somehow, and in an intrinsically inscrutable way, accounts for all that there is. The explanation of a lesser entity in terms of a greater one is a perversion of what it means to explain.
But the crux of the argument is not wholly the superiority of science as a mode of understanding the physical world: it is whether that physical world is the entire world, and whether there is any aspect of existence that necessarily lies outside the kingdom of science. If there is, then science cannot claim to be anything more than a partial contributor to global understanding. If there is not, then science is at least potentially capable of providing complete understanding of all there is.
Here, though, we must be very careful to distinguish between questions that have been invented and questions that at least seem to be real. Only the latter are likely to lead to true understanding of the world; the former merely expose the psychological condition of individuals and societies who invent them. I am afraid that, in my view, most of the questions that so exercise the religious are of the former, empty kind. Thus, whereas it may seem to be a perfectly legitimate question to ask, What is the purpose of this universe?, in fact that question is a transposition from everyday life. There is no need for this universe to have a purpose: it could be a wholly purposeless accidental entity.
Because religion implicitly asserts that science cannot divine the purpose of the universe, the religious conclude that science's orb is incomplete. That, of course is illogical, for religion cannot be allowed to invent illusory hoops for its adversaries to leap through: hoops, yes; illusory hoops, no. There are several examples of the invention of such hoops, including life after death (not a jot of evidence, if wishful thinking is excluded), the soul (ditto), and the existence of evil in a world created by an infinitely loving God (a trivial problem if there is no such God).
Somewhere on the borderline between the invented and the real lies the question of the human spirit and its associated qualities, such as love and aesthetic appreciation. I grant that these qualities, or at least their physiological appurtenances, exist. The question, then, is whether science can elucidate them.
There is no evidence that it cannot, and it is not unreasonable to suppose that it can without resorting to supernatural importations. Love is a complex emotion, involving genetically controlled responses, hormonal excretions, and intellectual reflections and considerations. Science can elucidate such a condition, even though it will probably never purport to be able to predict whether one individual will fall in love with another (although even dating agencies have some success in that field). Mysterious and complex love may be, but it certainly holds open the prospect of elucidation. Aesthetics, too, is not inconceivably comprehensible. Acts of valor, heroism, creativity, grandeur, and criminality all lie within the domain of psychology, and psychology is at least a twig if not a full-blown branch of science. Complex, agreed; unpredictable, maybe; but not closed to science.
There is of course one big, cosmically big, seemingly real question: Where did it all come from? Here we see most sharply the distinction between the methods. Religion adopts the adipose answer: God made it — for reasons that will forever remain inscrutable until, perhaps, we become one with Him (that is, until we are dead). Such an answer, while intrinsically absurd and evil in its implications, appears to satisfy those for whom God is a significant part of their existence. Science, in contrast, is steadily and strenuously working toward a comprehensible explanation. Witness the extraordinary progress that has been made since the development of general relativity at the beginning of the twentieth century. Though difficult, and still incomplete, there is no reason to believe that the great problem, how the universe came into being, and what it is, will not be solved; we can safely presume that the solution will be comprehensible to human minds.Moreover, that understanding will be achieved this side of the grave.
In short, whereas religion scorns the power of human comprehension, science, the nobler pursuit, respects it.