With the decline and fall of the Roman empire, and the rise to power of Christianity, learning was driven from Europe and found refuge among the Arabians. This brings us to the dark or middle ages. It is in the interpretation of the phenomena of this period, that bourgeois free thinkers like Clodd and Draper break down. They tacitly assume that in Europe evolution was suspended for over a thousand years; and all because of the Christian church. They fail to recognize that deeper cause, the medieval form of wealth production, which gave the church its power to repress learning in the interest of the lords of the land, among which the church herself was greatest; owning as she did one-third of the soil of Europe. The bourgeois radical cannot perceive that during this period social processes were being gradually transformed and that an economic foundation was being laid that would make possible the renaissance and put science in an impregnable position, and make the progressive acceptance of evolution inevitable. Engels says: “The Middle Ages were reckoned as a mere interruption of history by a thousand years of barbarism. The great advances of the Middle Ages--the broadening of European learning, the bringing into existence of great nations, which arose, one after the other, and finally the enormous technical advances of the fourteenth and fifteenth centuries--all this no one saw”. But it cannot be denied that this was a terrible period for any thinker who had the misfortune to be born in it. All that was great and noble in the thought of Greece and Rome was rigorously suppressed. The “perfecting principle” of Aristotle was wrested to theological uses. An emaciated form of his philosophy, and a literal interpretation of the scriptures, constituted the only permissible studies. Outside this dilution of Aristotle, the only thing in Greek thought which appealed to the medieval mind was the Pythagorean mystical use of numbers. The conclusions reached by that method were truly remarkable, especially when we remember that they engaged such notable men as Augustine, the celebrated Bishop of Hippo. These are examples: Because there are three persons in the trinity, Father, Son, and Holy Ghost, three orders in the church, bishops priests and deacons; three degrees of attainment, light, purity and knowledge; three virtues, faith, hope and charity, and three eyes in a honeybee; therefore, there can only be three colors, red, yellow and blue. Because there were seven churches in the apocalypse, seven golden candlesticks, seven cardinal virtues, seven deadly sins and seven sacraments; therefore, there could only be seven planets and seven metals. Because there were seventy-two disciples and seventy-two interpreters of the old testament and seventy-two mystical names of God; therefore there must be no more and no less than seventy-two joints in the human body.