41. Three aphorisms from Diderot, Philosophical Thoughts; Marivaux, The French Spectator; and Voltaire, ‘Fanaticisme’, Portable Philosophical Dictionary67
Being a non-believer is sometimes the vice of a fool, whereas being a believer can be the flaw of a clever man.
Diderot

A philosophers’ dinner by Jean Huber68 (c.1772): https://commons.wikimedia.org/wiki/File:Un_dîner_de_philosophes.Jean_Huber.jpg
My neighbour must be good to me, for if he were not, he knows it would be wrong; I must be good to him, because I know the same thing. Shame on anyone who breaks this fair contract.
Marivaux
There are no other remedies for this epidemic apart from the philosophical spirit which, if it is communicated from one person to the next, will finally mellow human behaviour and guard against the outbreak of evil; however, once the evil has taken hold, there is nothing to do but flee and wait until the air is clear once more. Laws and religion are not strong enough to cure this plague of the soul; religion, far from being a healthy remedy in this case, turns into poison within corrupted minds.
Voltaire
Read the free original text online (facsimile) of Diderot’s Pensées philosophiques, in Œuvres philosophiques, 1772 edition: https://books.google.co.uk/books?id=SUJw-NMCZ_4C&pg=PA30
Read the free original text online (facsimile) of Marivaux’s Le Spectateur français, in Œuvres complète, 1830 edition: https://books.google.fr/books?id=1QI6AAAAcAAJ&pg=PA211
Read the free original text online (facsimile) of Voltaire’s Dictionnaire philosophique portatif, 1765 edition: https://books.google.co.uk/books?id=SzYHAAAAQAAJ&pg=PA191
67 Denis Diderot, ‘Pensée xxxii’, in his Œuvres philosophiques et dramatiques de M. Diderot, Amsterdam: 1772; Marivaux, Le Spectateur français, in his Œuvres complètes de Marivaux, Paris: Cabanis, 1830; Voltaire, ‘Fanaticisme’, in his Dictionnaire philosophique portatif, 1764, pp. 190-193.
68 Voltaire has his hand up, Diderot is in profile. To Voltaire’s right is d’Alembert. On Diderot’s left is Marmontel. The person with his back to us may be Condorcet. Rousseau is notable by his absence: Voltaire and Rousseau detested each other.