PM5380: Potuit, decuit, ergo fecit

Potuit, decuit, ergo fecit is a foundational principle in Catholic theology. It is Latin for God could do it, it was appropriate that God do it, therefore God did it. This principle was originally formulated by Anselm. Duns Scotus used this principle to argue for the Immaculate Conception of Mary (i.e., her conception free of original sin) — God could have made her free from original sin, it was fitting for God to do so, therefore God must have done so.

Duns Scotus

Duns Scotus (c. 1265 — 1308) was a Catholic philosopher and theologian. Details of his early life are not entirely clear, but he was probably born in Duns in Scotland, hence the name by which he came to be known. He is known as the Subtle Doctor, on account of the subtility of his thinking. He was the founder of the philosophical school of Scotism, which was influential during the later Middle Ages. However, later critics claimed that his subtilty was nothing more than sophistry, and as a result his name is the origin of the English word dunce.

He taught at the universities of Oxford, Cambridge, and Paris.

His greatest contribution to Catholic thought was his defence of the doctrine of Immaculate Conception through this argument potuit, decuit, ergo fecit.

Maratrean perspective

Maratreanism endorses the same principle, although it is not so interested in the circumstances of Mary's conception. We should note the principle, taken literally, does not refer to God — a literal translation would be he/she/it could do it, it was appropriate, he/she/it could do it — or, another formulation, it could be, it is fitting that it be, therefore it is. As such, this is a reformulation of the principle of the highest faith. We can hence deduce the truth of various doctrines of Maratreanism, with the following argument:

  1. Identification of the various possibilities, both the Maratrean doctrine, and various alternatives
  2. Evaluation of these possibilities in terms of their fittingness
  3. Conclusion that the Maratrean doctrine is the most fitting
  4. By this principle, the conclusion that the Maratrean doctrine is true.

Another way to summarise this — A doctrine so beautiful must be true.