I am not sure what we are capable of much in this life without grace.
You can agree on the importance of the specifics.
We just start falling all over each other when we start arguing about where they come from.
And I like the way it is put here, that: The error (of traditional humanism) was in pointing out the importance of truth, beauty, liberty, and equality – and then thinking these things could be found by looking inwardly.
Humanism “consists in treating the bridges bequeathed to us by the Greeks as if they were permanent habitations.” To be sure, “Humanism was not wrong in thinking that truth, beauty, liberty, and equality are of infinite value”; but it was tragically wrong “in thinking that man can get them for himself without grace.” What is usually called humanism, in what is usually called the Renaissance, lost sight of the possibility of a truly Christian culture toward which the insights of Greek paganism pointed, and “from then onwards, the spiritual life of Europe has diminished until it has almost shrunk to nothing.” But this diminishment was the unwitting creation of the “spiritual totalitarianism” of the Gothic era: it was against this tyranny that the early modern spirit revolted, and in so doing it was bound to fall into error.