Potuit, decuit, ergo fecit!

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Duns Scotus (“the Scot”) in the 14th century was also a stalwart defender of the Immaculate Conception and also used the “Potuit – decuit – ergo fecit” argument.

The argument is useful for the simple reason that it disarms opponents that deny the Immaculate Conception. It is still useful today in sharing your faith with Protestants.

Simply ask, “Could God make a person without original sin?” (potuit)

Next ask, “Would it have been decent or fitting for the Son of God to have his mother 100% pure and loyal to him?” (decuit)

Then follows the conclusion, “Well then, if He could do it and it was fitting, then He did do it. Mary was conceived immaculately (conceived without stain – macula is Latin for “stain”).

Therefore (ergo), God did make his Mother without original sin. (fecit)

So “Potuit, decuit, ergo fecit!” Memorize these four Latin words and you will defend Our Lady with honor.

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