The good Christian should beware of mathematicians, and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of Hell –St Augustine, De Genesi ad Litteram, Book II, xviii, 37
See, the Catholic Church is against science! Well maybe not. Julian Havil in his excellent book Gamma: Exploring Euler’s Constant offers a helpful gloss: “here, ‘mathematician’ means ‘astrologer'”.
So WDTTRS (what did the theologian really say)?
It doesn’t take much thought to see here that Augustine does not use the word mathematician in its modern sense. Mathematicians today don’t make prophecies. They might work out some arcane things, such as the gamma-filtration of oriented cohomology of complete spin-flags (no, I don’t know what that is, either) but it is all very rational and logical, and to someone who loves the field, such things hardly darken the spirit.
In a sound-bite age, it’s hard to take the time to look at something in context, but I’m going to do it anyway. Here’s the whole thing, with my emphasis:
Hence, we must admit that when astrologers speak the truth, they are speaking by a mysterious instinct that moves a man’s mind without his knowing it. When this happens for the purpose of deceiving men, it is the work of evil spirits. To these spirits some knowledge of the truth about the temporal order has been granted, partly by reason of their keen and subtle senses, since they possess bodies of a much more subtle nature than ours, partly because of their shrewdness due to the experience they have had over the long ages they have lived, partly because the good angels reveal to them what they themselves have learnt from Almighty God, at the command of Him who distributes man’s merits by the right principles of His hidden justice. But sometimes these wicked spirits also feign the power of divination and foretell what they themselves intend to do. Hence, a devout Christian must avoid astrologers and all impious soothsayers, especially when they tell the truth, for fear of leading his soul into error by consorting with demons and entangling himself with the bonds of such association.
Nothing in there about the disciples of Euclid and Eratosthenes.
Augustine had no truck with astrology. He even anticipated the apparently modern objection that twins born under the same configuration of stars have entirely different fates. So if he has a beef with astrologers, why does he rail against the mathematici? Blame semantic shift. Mathematicus doesn’t mean today exactly what it did in the fourth century. Back in the day, what we now call mathematics was often employed in the service of divination: astronomy was as much about casting horoscopes as anything else, and gematria, what we now call numerology, was all the rage, even in the Bible, where John’s number of the Beast is a numerological reading of “Nero Cæsar”.
So did Augustine have anything to say about mathematics, as we understand the term today? Well, he had a lot to say about everything, including mathematics. Here’s a summary if you’re interested.