The man who called himself ‘the apologist of strong passions,’ who thought marriage ‘a senseless vow,’ and ‘was always very near to the position that there is no such thing as an absolute rule of right and wrong,’ would not be likely to be faithful. He was not faithful. There soon loomed on the scene a Madame Puisieux (the wife of a barrister), aged about five-and-twenty, charming, accomplished, dissolute. Diderot plunged headlong into love with her, as he plunged headlong into everything. To be sure, she was abominably extravagant and always wanting money. To gratify her demands Diderot wrote, most characteristically, an ‘Essay on Merit and Virtue,’ and brought Merit and Virtue the sum he received in payment. But Madame’s love of fine clothes was insatiable. Between a Good Friday and Easter Day her lover composed for her the ‘Philosophical Thoughts,’ which first made him famous, which were paid the compliment of burning, and for which his mistress received fifty louis. The history of the inspiration of masterpieces would afford a peculiarly interesting insight into human nature. It may be set down to the credit of Madame Puisieux (history knows of nothing else to her credit) that her rapacity at least forced this incorrigible ne’er-do-weel upon his destiny, and first turned Diderot, the most delightful scamp in the capital, into Diderot the hard-working philosopher and man of genius. Nanette came home presently, having earned the love and admiration of the little family at Langres, and put up with Madame Puisieux as best she could. Other children were born to her, and died; only one, little Angélique, survived. Of the quantity of Diderot’s love for this child there is no doubt; it is only the quality that is questionable. Self-indulgent to himself, he was weakly indulgent to her. She was apt at learning, so, when they both felt inclined, he taught her music and history. Later, when she was ill, he wrote letters about her full of ardent affection; but he left her mother to nurse her and went off gaily to amuse himself with his friends, and then took great credit for having given ‘orders which marked attention and interest’ in her, before he went out and dined with Grimm under the trees in the Tuileries. Of course Angélique loved the lively good-natured father much the better of the two. Of her mother the daughter herself said afterwards, with a sad truth, that she would have had a happier life if she could have cared less for her husband. However, Denis was working now, and working meant, or should mean, ease and competence.