Dei Filius, Of Revelations, Canon 1

II.

Of Revelations.

1. If any one shall say that the one true God, our Creator and Lord, can not be certainly known by the natural light of human reason through created things: let him be anathema.

Translation: Henry Edward Manning, Petri Privilegium (1871), reproduced in Philip Schaff, Creeds of Christendom II, via CCEL.