We normally think of science as the champion of reason, but at the turn of the first millenium, it was religion that gave rationalism a big boost. By that time, Aristotle had become the ultimate authority on just about everything, and thinkers were beginning to realize that they were now split between two ultimate authorities: their religious literature and Aristotelian literature. No problem, they thought; their task was merely to reconcile Aristotle with their religious texts. For each of the three monotheistic faiths, many thinkers attempted the task of reconciliation; but I shall confine my comments to three of the greatest: Averroes for Islam, Maimonedes for Judaism, and Thomas Aquinas for Christianity. Averroes was first of the three -- no surprise here, as Islam was the leading intellectual force of the age. Maimonedes, brought up in Islamic Spain, was not far behind. And, as we might expect from the pitiable state of Christian civilization at the time, Thomas Aquinas brought up the rear.
But more important is the way the rationalists were treated by their co-religionists. Islam, already sinking into the fetid quagmire of conservatism by the turn of the millenium, rejected the rationalists forcefully. Their works were burned and many of them suffered banishment, imprisonment, or execution. The Jews were only moderately angered by the works of their rationalists; a few were executed, and some of their books were burned, but for the most part their rejection of rationalism was civil. Many Christians were also incensed by the attempt to subordinate faith to logic, and there were sporadic acts of abuse. But -- and this was the single most important factor in setting Europe on the road to world domination -- the Christians accepted the rationalists in their midst. Interestingly, Thomas Aquinas set out to challenge the Islamic-flavored rationalism that had become the vogue at Christian universities, and ended up rephrasing it in Christian terminology, boosting the concept enormously. His results were so convincing that an entire school of thought sprang up around Aquinas’ work, eventually leading to a movement within Christian philosophy called Scholasticism.
Scholasticists were theistic rationalists. Idealists at heart, they refused to believe that faith and reason were incompatible. They felt that religion needed only some tidying up at the edges to be reconciled with logic. Sure, some superstitions and myths would be rejected in the process, but these were, in their minds, peripheral to the core of faith. And so they pursued logic, in the process advancing pure logic considerably. They developed an entire system of reasoning, with terminology (quidities, etc) and methodology. For two hundred years they honed their logic to razor sharpness. But in the process they encountered too many conflicts with faith. These were the people who brought us the raging the debate about how many angels could dance on the head of a pin. By the fifteenth century, Scholasticism had degenerated to feckless, pointless cleverness, and stripped Christianity of any sense of feeling.
From the outset, Scholasticism had attracted conservative critics, and as it became apparent the no broad reconciliation between faith and reason could be achieved, the opposition grew stronger. For several centuries the opposition was just as feckless as Scholasticism, because the opponents equated Scholasticism with learning and therefore concluded that faith demanded ignorance — a formula that kept them out of all positions of intellectual power. And indeed some Christian thinkers, preferring logic to faith, drifted into discreet agnosticism. So things stood when Gutenberg turned everything upside down with his invention.