On another blog last month I was asked by some friends to comment on a thread about Christianity's role in the progress of science. Other things were being discussed there, such as whether Martin Luther was a despicable ass or an admirable genius, which I didn't comment on because I know too little about the matter to add anything worthwhile. But the history of science is my Ph.D. field, so I could comment on that with some authority. And I did. What follows is expanded and adapted from what I said, and completely supercedes my comments there as far as I'm concerned. Don't worry, though. My blog isn't always going to be about the history of science.
It is becoming popular now to claim Christianity "responsible" for the scientific revolution (Stark, Jaki, etc.). My dissertation will refute much of that thesis, in about two chapters altogether. But we need to keep distinct the claim that Christianity did not actively oppose science (which is sometimes true, depending on how you define "oppose") and the claim that Christianity was necessary for the scientific revolution (which is certainly not true), as well as various claims in the middle--like "Christianity wasn't necessary, but helped," which again depends on how you define "helped"; or "all theologies can find a compatible incentive towards science, and Christianity is a theology like any other," which is true, depending on how you define "Christianity" and "theology"; and so on. Likewise "our concept of science is an outgrowth of Christian theology" is no more true than "our concept of science is an outgrowth of pagan theology." Modern science grew up in a Christian context, but only by re-embracing ancient scientific values against the grain of the original Christian mindset. In turn, those ancient scientific values grew up in a pagan context. As with Christianity, that's not causality, it's just circumstance.
However, in all this the one claim that cannot be sustained is that Christianity "encouraged" science. Had that been the case, then there would not have been almost a thousand years (from roughly 300 to 1250 AD) of absolutely zero significant advances in science (excepting a very few and relatively minor contributions by Hindus and Muslims), in contrast with the previous thousand years (from roughly 400 BC to 300 AD), which witnessed incredible advances in the sciences in continuous succession every century, culminating in theorists whose ideas and findings came tantalizingly close to the scientific revolution in the 2nd century AD (namely, but not only, Galen and Ptolemy). You can't propose a cause that failed to have an effect despite being constantly in place for a thousand years, especially when in its absence science had made far more progress. Science picked up again in the 1200's precisely where the ancients had left off, by rediscovering their findings, methods, and epistemic values and continuing the process they had begun.
Sure, this was done by Christians, but only against the dominant grain, and at first only very slowly, and only by redefining what it meant to be a Christian in a way that would have been nearly unrecognizable to the Christians of the first four centuries, and was diametrically the opposite of what Christians of the early middle ages would have tolerated. A fair example is the treatment of John Philopon in the 6th century, possibly the only innovative "scientist" (if he can be called that) in the whole of Christian history before the 13th century: he was branded a heretic and everything he did in the sciences was effectively ignored. Though he wasn't condemned for being a scientist, he was condemned for thinking for himself in matters of theology, precisely in his effort to make science and religion compatible. But by opposing exactly that process, the Church killed any prospect for science under its watch for nearly ten whole centuries. You can call it collateral damage, but it's damage all the same. An accidentally dead Iraqi is still a victim of war, and so was medieval science a victim of Christianity.
Aquinas and Roger Bacon are often wheeled out here, but they are also examples of what I'm talking about: both post 1200 AD (hence again a thousand years too late), and both responding to the revival of ancient (pagan) scientific and philosophical literature and ways of thinking. At that point, that meant mostly just some Aristotle--whose work had already become largely obsolete even in antiquity. The real discoveries of what the ancients had achieved after him would take another century or more, and even then all they had achieved was never fully realized until the 20th century. Hence the new ideas under Aquinas and Bacon were not inspired by Christianity but in spite of it. They were inspired, instead, by the recovered ideas of ancient pagans, and the challenges they posed to Christian ways of thinking.
Moreover, neither Aquinas nor Bacon did anything significant in science. Neither conducted any significant experiments or advanced any scientific field in any notable way. Bacon's protoscientific work has been much exaggerated and misrepresented in the literature, and Aquinas didn't do anything scientific at all, proto or otherwise--in fact, he fathered the "scholastic" approach to natural philosophy, which was the antithesis of science and the butt of every joke among scientists of the Renaissance. Thus, neither of them represent examples of an "encouragement to science." At best they represent examples of attempting to find a compatibility between two otherwise alien ways of thinking, with mixed and insufficient results. And even then they were not representative of their times--they were both acting against the grain (the Church had only recently banned the study of Aristotle and then reluctantly changed its mind), in efforts to reconcile Christianity as-it-was with better ways of thinking. They were both arguing, in effect, that Christianity had to change, and change fundamentally, to allow improvement, and yet neither of them understood science anywhere near as well as the ancients did, nor did either have any idea what the results would be of what they were asking for--had they known, they might both have changed their minds about their respective projects.
Even so, it is still wrong to say, as a friend of mine did, that "Christianity has spent the majority of its 2000-plus years opposing science with theology, with the most brutal means at its disposal." As someone else said, that’s a gross oversimplification, exaggerated and excessive. But so is the claim that Christianity never presented any obstacles to science, or that it only occasionally did so. The reality is that it constantly presented obstacles, usually indirectly (but just as potently), and sometimes directly, but rarely "with the most brutal means at its disposal." In effect, using a whole arsenal of tactics, early (and especially early medieval) Christianity bitch-slapped all thinking that could have any tendency to support and inspire an embrace and pursuit of scientific values. This hostility and effort wasn't aimed at science directly, but at liberality of thought, and most of all, at the notion that evidence available to everyone is the only supreme authority in all debates of substance. The Church very definitely and actively opposed that idea. And even before the consolidation of the Church, as I show in my dissertation, most Christians were uniformly hostile to the whole system of scientific values, condemning them as vain, idolatrous, arrogant, and unnecessary, if not outright dangerous. It took a long, gradual process to finally change minds on that score.
From Aquinas and Bacon (and their peers) to the dawn of the scientific revolution spans a period of roughly 300 years, and it took over a thousand years for Christianity to finally produce an Aquinas or a Bacon--at least in terms of actual intellectual authority and influence. In some respects, Origen and Philopon were perhaps comparable, but both were branded heretics and their scientific values rejected by their Christian peers. And even in the 13th and later centuries opposition remained, despite a growing tide against it. And though that opposition to scientific values has gradually dwindled ever since, it remains large and powerful enough to elect the presidents of a world superpower. This is not a problem to be regarded flippantly. This is the bugbear in Christianity's closet, and Christianity has failed to kill it for two thousand years. Christianity must be judged by that very failure.
It has also been noted that "sure there have been conflicts, but many (if not most) of the great scientists of history have also been religious," like Newton and Galileo. Indeed. Most of the greatest scientists in antiquity were also religious. Galen and Ptolemy were pagans, even creationists. All that proves is that people can manipulate their religions to be compatible with a scientific mindset--often by compartmentalizing, which means only embracing scientific epistemic values when answering questions that don't challenge precious religious dogmas, which is really the issue. A religion will be capable of being made compatible with science only insofar as it restrains its dogmatic commitments far enough that science is unlikely to encroach upon them. The problem is that science always will encroach upon them eventually, and when that happens there will be only two responses to choose from: give up precious dogmas (in other words, change your religion to be compatible again with science) or stand your ground and oppose science (which is how the Intelligent Design movement has responded to evolution, for example, and soon will respond, I suspect, to advances in neuroscience).
It is certainly true that Christianity, like all religions, can be "retooled" to go either way, but not everyone will go the same way, hence there are Christians who are okay with science, and Christians who fight it tooth and nail. The problem with religion is exactly this: it keeps around this tendency to push a segment of the population against science, even as other segments find ways to make religion and science compatible. This tension is inherent in religious thinking and will never go away until religion goes away altogether. To be clear, by "religion" here (since I use that word in a different sense in other contexts) I mean any belief system that places faith above evidence and reason, accepting evidence and reason only when they do not conflict with an accepted set of faith-claims. Hence those two options for a religious person faced with scientific facts that contradict her faith: she can change her faith (and thus place science, and hence evidence, first in authority when choosing what to believe) or oppose science. Religion always produces the latter sort of person, even when it also produces the former, and that's what's wrong with it.
Hence the problem I am pointing to is not unique to Christianity. It existed even in the pagan world before Christianity. Anaxagoras was (at least allegedly) prosecuted by the Athenians for blasphemy simply for theorizing the sun is a hot stone. Other pagans tried to launch a blasphemy prosecution against Aristarchus when he claimed the earth revolves around the sun. Lucian had a contract put out on his head for claiming the miracles of a certain cult had natural explanations in ordinary fraud. Likewise, Neoplatonism sometimes resembled medieval Christianity in its disinterest in empirical studies and obsession with mystical approaches to science, often through armchair reasoning and "inspired intuition." But there was one enormous difference: science-hating pagans never had the institutional power and clout to enforce their views on the general society (all Anaxagoras and Aristarchus had to do to avoid their influence was leave town), but the Christians achieved and maintained precisely that power for many centuries, and so pervasively there was no way to escape their influence. What they did with that power was sufficiently scary that we should never want that to happen again.
Yet for all that, what I am asserting here is not that Christianity alone is responsible for the Dark Ages. I find Christianity to be a symptom, not a cause, of the fall of the Roman Empire and the ideals it founded or fought over (see my discussion The Rise of World Christianity). What I am saying, however, is that Christianity didn't do any good. It neither corrected what had gone wrong nor reintroduced any striving for the dreams and aspirations of earlier Greek and Roman idealists, but to the contrary, Christianity embraced a partial and sometimes full retreat from them. Hence Christianity did not kill science. But it made no effort to rescue and revive its ideals, and instead let them drown, with little sign of regret, and in some cases even to praises of its demise. Thus, Christianity was bad for science. It put a stop to scientific progress for a thousand years, and even after that it made science's recovery difficult, painful, and slow.
I am also not saying Christianity "necessarily and uniformly" stomps out science, only that we cannot claim Christianity "encouraged" science during its first thousand years, even if some significant Christian factions did later or now do. Christianity threw up a great many obstacles to the recovery of pagan scientific values during and after its first thousand years, and to a lesser extent is still doing this today. But again I am not saying all Christianity does this now. Rather, I am saying Christianity will always generate factions that do, as it always has. And the last thing we want is to allow one such faction back in power, as had been the case during Christianity's first thousand years in the saddle. We must not go back to the Dark Ages.
People still raise objections to various points above.
One might object and say, "Historians no longer believe there were any 'Dark Ages'!" That depends on what you mean by Dark Age. What I mean by that term here is any era in which a considerable amount of knowledge is lost, especially scientific and technical knowledge, while the ruling zeitgeist looks backwards to a time before more enlightened ways of doing things were embraced. The loss of over 90% of all literature, and the corresponding historical and scientific knowledge it contained, is a fact. The abandonment of the highest civilized, technological, historical, and scientific ideals of the early Roman elite, in exchange for more barbarian ways of thinking and doing things, is a fact. And that is, by my definition, a Dark Age.
Far less was recorded during the middle ages, and far less accurately, than had been the case in classical times, and only a small fraction of what was recorded before was preserved, and even what survived remained known to astonishingly few, and put to good use by even fewer. Again, by my definition, that's a Dark Age. At the same time, the greatest aspirations of the pagans, with their struggling ideals of democracy and human rights, just like their empirical ideals and the scientific spirit they inspired, were chucked out the window in favor of more primitive ideas of "god-given" kings constantly at war over a feudal society, pontificating popes and pulpit-thumping preachers, burning witches and the widespread embrace of hocus pocus, even by the educated elite. That's a Dark Age. And however much one might not like it, we had one.
One might object and say, "Well, it wasn't totally dark, some improvements in technology were made, some history was recorded, a lot of ancient knowledge preserved." But that would only be a valid point if I were claiming a Pitch Black Age. Even with a little light, it was plenty dark. Moreover, by far most of what was invented, improved, or preserved came after the 12th century. The Dark Ages preceded that. Even what was preserved through to the 12th century was only barely so, much of it only in a few isolated places, sometimes only in a single manuscript, perhaps two or three, scattered across the world and collecting dust on forgotten shelves, often damaged or surviving only in translation. And by far most of what survived was preserved only in the comparably wealthier Middle East, where times were never as dark as they definitely became in Europe. Hence the Dark Ages more aptly describes the history of Europe than of the medieval Middle East, although even the latter experienced a notable decline from pre-fall Rome in every aspect of civilization and culture.
One might object and say, "Well, even you admit Christians produced one real scientist, John Philopon, so clearly Christianity was doing something to encourage science!" That's hardly sound reasoning. When the controlling religion generates only one significant scientist (and he was barely even that) in a thousand years spanning hundreds of millions of adherents, you cannot claim it "encouraged" science. That's like finding a single poodle-juggler in a thousand years of Christian history and claiming Christianity encouraged poodle-juggling. For a thousand years Christianity failed to inspire society to take up the values, especially the scientific values, that many pre-fall Romans had embraced, and this had the effect of stalling scientific progress for a thousand years. One might quibble over the causes of that fact, but it's still a fact.
One might object and say, "You are much too vague about what these mysterious 'scientific values' are that Christianity abandoned and came to accept only with difficulty and never universally." Well, then let it be known what I mean. By phrases like "scientific ideals," "scientific values," "scientific mindset," I do not mean potentially dogmatic activities like observing the movement of the stars or performing textbook surgery, but a system of beliefs that produces advances in knowledge, including a belief that public evidence and verifiable reason trump all authority in explaining what is and can be, that persuasion by appeal to observable evidence and sound logic is the only valid means of gaining consensus about the truths of this world, that this requires embracing everyone's intellectual freedom to accept, reject, or propose any idea they please, and that it is valuable and good to devote your life in this way to the pursuit of progress in understanding any aspect of nature or existence. Those are the scientific values of which I speak.
One might object and say "Christianity never had such a swift and overwhelming cultural influence in the middle ages as to blot out a 900 year course of scientific progress by itself!" Yes, it did. The Church owned all scriptoria and chose which books to copy and which to toss in the dustbin. The Church controlled all schools and chose what would and would not be taught in them. All Europeans that lived in those thousand years were under the thumb of priests who quickly opposed any freedom of thought that they imagined could ever pose a threat, and to that end had the full force and power of government and social influence at their command. The Church decided what values would be preached every week to all the masses, and which values would be derided. As I said, that is precisely the power even the antiscientific few among the pagans never had. The effect is undeniable: the abandonment of a shocking amount of scientific knowledge and, far more than that, the abandonment of the scientific values that had until then produced and improved that knowledge, and could have continued doing so.
One might object and say, "Characterizing classical antiquity as encouraging a general 'liberality of thought' is at best simplistic, and in many cases false." Not so. The reality is, freedom of thought not only existed, but was widely practiced and embraced, across the whole of the Roman world before Christianity came to power. Although things did start to roll toward fascism during the chaos of the 3rd century (as I explain in that linked discussion above), before then the vast diversity of philosophical and scientific sects and schools is evidence enough. Such open diversity could not have been the case had freethought been effectively opposed, and would not have been the case had it not been widely enough encouraged. Political freedom of speech was limited. But science was apolitical. Indeed, the phenomenon of "eclecticism," a widespread independence of thought whereby scientists and philosophers could pick and choose principles and theories from among all sects and schools as they themselves saw fit (rather than aligning themselves with only one) was the dominant intellectual fashion under the Hellenistic Greeks and especially the Romans. This is a fact of the times, a social and intellectual phenomenon that Christianity often attacked and then effectively eliminated.
In contrast, the groups that opposed science in classical antiquity were small, few, rare, and ultimately powerless. That is exactly the opposite of what happened under Christianity. Even if Athens was occasionally inhospitable, there was always Alexandria, Rome, Rhodes, Samos, Antioch, Ephesus, Pergamum, London, Marseilles, and countless other cities to retreat to in freedom--where, in fact, most science in antiquity was actually done. Hardly any science was done at Athens, in the whole history of antiquity--even much of Aristotle's scientific work was conducted on Lesbos. And under the Romans, what the Athenians had rarely attempted would have been outright illegal--which is why Lucian had to be dispatched clandestinely by assassination: his religious foes could no longer use the government to suppress his intellectual freedoms, exactly the opposite of the way things were under the thumb of the Church.
Yet even before the Roman Empire, neither Aristarchus nor Anaxagoras (nor any other scientist in the whole of antiquity) were killed or jailed or fined or affected in any significant way at all, beyond not being welcome in one city for a brief time. Hence their work continued uninterrupted, and their books were faithfully preserved and disseminated--until Christians (yes, Christians) decided they weren't worth copying anymore. Hence their books are lost to us. We have a hundred volumes of Jerome's inordinately boring letters, but not a single volume on Aristarchan heliocentric theory. Yes, heliocentric theory--over a thousand years before Copernicus. That is the measure of medieval Christian values.
Perhaps, indeed, had Christianity collapsed and a fanatically religious Neoplatonism produced a universal Church in the 4th century and thereafter for a thousand years, it, too, would have failed to encourage any significant scientific thinking. In which case I would be saying the same thing I am now: religion, whether Neoplatonic or Christian or Spaghettimonsterish, is bad for science and always will be, so long as it has any power to undermine or impede freethought, and insofar as it will (and it will) always generate antiscientific enclaves whom we will forever have to battle just to maintain the status of scientific knowledge and values. This is how it was. This is how it is. And until religion is gone, this is how it will always be.