The First Vatican Council, Dei Filius (1870) Dogmatic Constitution on the Catholic Faith defined the following:

If anyone shall have said that the one true God, our Creator and our Lord, cannot be known with certitude by those things which have been made, by the light of human reason: let him be anathema.

(Item #1 of 2. On revelation set of canons)

From what I understand, this pronouncement was motivated at the time by those who were denying natural theology.

Can someone elaborate on some of the specifics regarding those who were denying "natural theology" at the time that Pope Bl. Pius IX made this (de fide) declaration?


1 Answer 1


That canon anathematizes the fideists, who thought

that faith is the only or ultimate source of all knowledge of God and spiritual things. The name was originally coined by followers of Kant (1724-1804) and Schleiermacher (1768 -1834), both of whom denied the capacity of reason to know God or the moral law with certainty. (Etym. Latin fides, belief; habit of faith; object of faith.)

—John Hardon, S.J., Catholic Dictionary, "Fideism"

  • Thank you for this answer.
    – DDS
    Oct 27, 2023 at 13:43

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