I'm going to add more and more quotes as I get deeper into the book.
Religion is in perpetual conflict with the spirit of free research. The Church's opposition to science was sometimes so violent that it struck off sparks. The Church, with a clear awareness of her interests, has made a strategic retreat, with the result that science has lost some of its aggressiveness.
The present system of teaching in schools permits the following absurdity: at 10 a.m. the pupils attend a lesson in the catechism, at which the creation of the world is presented to them in accordance with the teachings of the Bible; and at 11 a.m. they attend a lesson in natural science, at which they are taught the theory of evolution. Yet the two doctrines are in complete contradiction. As a child, I suffered from this contradiction, and ran my head against a wall. Often I complained to one or another of my teachers against what I had been taught an hour before—and I remember that I drove them to despair.
The Christian religion tries to get out of it by explaining that one must attach a symbolic value to the images of Holy Writ. Any man who made the same claim four hundred years ago would have ended his career at the stake, with an accompaniment of Hosannas.
Religion draws all the profit that can be drawn from the fact that science postulates the search for, and not the certain knowledge of, the truth. Let's compare science to a ladder.
On every rung, one beholds a wider landscape. But science does not claim to know the essence of things. When science finds that it has to revise one or another notion that it had believed to be definitive, at once religion gloats and declares: "We told you so!" To say that is to forget that it's in the nature of science to behave itself thus. For if it decided to assume a dogmatic air, it would itself become a church.
Does the knowledge brought by science make men happy? That I don't know. But I observe that man can be happy by deluding himself with false knowledge. I grant one must cultivate tolerance.