Shaftesbury, and Diderot after him, ennobled human nature by placing the principle of virtue, the sense of goodness, within the breast of man.

Diderot held to this idea throughout, as we shall see.

That he did so explains a kind of phraseology about virtue and morality in his letters to Madame Voland and elsewhere, which would otherwise sound disagreeably like cant.
Finally, Shaftesbury's peculiar attribution of beauty to morality, his reference of ethical matters to a kind of taste, the tolerably equal importance attributed by him to a sense of beauty and to the moral sense, all impressed Diderot with a mark that was not effaced.

In the text of the Inquiry the author pronounces it a childish affectation in the eyes of any man who weighs things maturely to deny that there is in moral beings, just as in corporeal objects, a true and essential beauty, a real sublime.

The eagerness with which Diderot seized on this idea from the first, is shown in the declamatory foot-note which he here appends to his original.[41] It was the source, by a process of inverted application, of that ethical colouring in his criticisms on art which made them so new and so interesting, because it carried aesthetic beyond technicalities, and associated it with the real impulses and circumstances of human life.[42] One of Diderot's writings composed about our present date (1747), the Promenade du Sceptique, did not see the light until after his death.