We know that Diderot assumed his role as a moralist and that he praised Greuze, among other things, because his painting educated and edited the viewer, giving him lessons of virtue. Although he fears that beauty as goodness often hurts, little is already necessary, in the Treaty of Beau, that Diderot associates the beautiful, except with the useful and the true, at least to the good (the Holy Trinity of the moral code), that is to say to a virtuous ideal conceived as an infallible source of happiness. The philosopher of the Enlightenment and his enlightened Reason will be recognized here. The century, for its part, will divert the notion to the advantage of the sublime, another ideal abstraction, inaccessible and unknown, to which all Romanticism (and Schiller in mind) will aspire until Baudelaire, who will see no more or less than an "anti-spleen".