The book is great because it brings together all of the factors that brought about Western Europe. I have however one criticism. The author tells about the Roman Catholic Church's excommunication of the followers of the Aristotelian philosophy of Averroes. Lewis implies, however, that this condemnation was scientifically backward like the condemnation of Galileo in later centuries. I would say the condemnation is the beginning of modern science since Aristotle and Averroe were being unscientific. The following quote is from the Bishop of Paris's Letter of Condemnation of 1277:
We excommunicate all those who shall have taught the said errors or any one of them, or shall have dared in any way to defend or uphold them, or even to listen to them, unless they choose to reveal themselves to us or to the chancery of Paris within seven days; in addition to which we shall proceed against them by inflicting such other penalties as the law requires according to the nature of the offense.... 25. That God has infinite power, not because He makes something out of nothing, but because He maintains infinite motion.... 66. That God could not move the heaven in a straight line, the reason being that He would then leave a vacuum....
The Bishop of Paris and his advisers from the faculty of theology at the University of Paris knew that vacuums did not exist in nature. However, they could see no reason why vacuums could not exist. They assumed that God thought the same way they did, and concluded that vacuums were possible. In other words, they were assuming that the universe was intelligible, which is what modern science is based on. The following quote of Albert Einstein is from D. Overbye, "Einstein Letter of God Sells for $404,000," New York Times, May 17, 2008:
The most incomprehensible thing about the universe is its comprehensibility.