Nobody quite knows how this works, but by and large it does work, and works for the better. Before Descartes, then, people didn't know much, but by comparison with present-day attitudes, they were sure of what they thought they knew, whereas after Descartes they knew a great deal more but were a lot less certain about it. The map of knowledge gets violently distorted. Some areas are obviously growing, other are either not growing at all or are contracting. This is not only because, being on the move, they are know to be unstable.
Successful knowledge gets specialised.
This makes it unavailable as a premise for one's vision of the world, or for one's social life. That is to say, there had for so long been a single category in terms of what everything was ultimately to be explained, namely God, that for a long time people went on looking for some other such single category in terms of which everything was ultimately to be explained. At first they thought they had found it in Science. Then you get Marxism, which tries to integrate History and Science into a single framework of ultimate explanation. Perhaps reality is, right to the very end of the road, pluralistic.