The First Cause, and Who Kept the Books

The argument in its crude form is familiar. Everything has a cause. The chain of causes cannot go back forever. So there is a first cause, and we call it God.

Stated that way it has an obvious flaw, and we will get to it. But first, a question that is almost never asked in a summary of medieval philosophy.

How did Aquinas have Aristotle to work with?

The Latin West had lost most of Aristotle. What survived in Europe was fragments and a few logical works. The rest of the corpus, the physics, the metaphysics, the biology, came back to European universities in the twelfth and thirteenth centuries in Latin translations made from Arabic.

For several centuries the serious philosophical work on these questions was being done in Arabic and Persian, and the European recovery is downstream of it.

Avicenna, in the eleventh century, took the causal argument far beyond anything in Aristotle. His version is not about a chain of events running back in time, which is the crude form and the weak one. It is about contingency. Some things might not have existed. Anything that might not have existed needs an explanation of why it does. You cannot explain the whole collection of such things by pointing at another member of it, so there must be something whose existence is not contingent, something that could not have failed to be.

That is a much better argument than the one about a chain of dominoes, and it is the one Aquinas is working with.

Then Al-Ghazali, around the turn of the twelfth century, wrote The Incoherence of the Philosophers: twenty chapters, each attacking a doctrine, most of them Avicenna's.

His position is regularly misdescribed as an attack on reason, and it is not. His argument is that the philosophers were claiming a certainty in metaphysics that their own methods could not deliver. Logic is excellent at what it does; it does not license the confident conclusions about the nature of God and the eternity of the world that were being drawn from it. That is a criticism of overreach, and it is closer to a demand for rigour than a rejection of it.

Averroes answered with The Incoherence of the Incoherence, which is among the great titles in the history of argument, and defended natural causality and the reliability of rational inquiry.

And it was Averroes whom the Latin universities read. He was known simply as The Commentator, the standard guide to a philosopher Europe had substantially lost, and his influence on Christian and Jewish philosophy in that period was enormous. Aquinas is in conversation with him constantly.

Now the objection, which deserves to be made properly rather than cheaply.

The cheap version is: if everything has a cause, what caused God, and if God does not need a cause, then the premise was false.

The better versions of the argument do not say everything has a cause. They say everything contingent requires an explanation, and then argue that something non-contingent is needed to terminate the explanation. God is not an exception to the rule; God is defined as the thing the rule does not apply to.

Whether that distinction is genuine, or a way of hiding the same move behind a definition, is the actual disagreement.

It is a better disagreement than the one people usually have, and you cannot get to it without knowing that Avicenna existed.