30. Three aphorisms from Diderot, ‘Letter to My Brother’, 1760; Voltaire, Treatise on Metaphysics, 1735; and Rousseau, The Citizen, or An Address on Political Economy, 176548
Portrait of Rousseau by Maurice Quentin de La Tour (after 1753): https://commons.wikimedia.org/wiki/File:Jean-Jacques_Rousseau_(painted_portrait).jpg
Philosophy is as far from impiety as religion is from fanaticism, but from fanaticism to barbarism is only a step.
Diderot
Adultery and love between men are allowed in many countries, but you will not find a single one in which you are allowed to break your word. This is because society can rub along perfectly well with adulterers and men who love each other, but not with people who pride themselves on deceiving each other.
Voltaire
Those citizens who deserve thanks from their country should always be rewarded with honours but never privileges, for the instant anyone is allowed to think what a fine thing it would be to disregard the law, the republic will teeter on the brink of disaster.
Rousseau
Read the free original text online (facsimile) of Diderot’s, ‘Lettre à mon frère’, in Collection complete des œuvres philosophiques, littéraires et dramatiques, 1773 edition: https://books.google.co.uk/books?id=Dj4HAAAAQAAJ&pg=PA141
Read the free original text online (facsimile) of Voltaire’s, Traité de Métaphysique in Œuvre completes, 1796 edition: https://books.google.co.uk/books?id=3iAHAAAAQAAJ&pg=PA520
Read the free original text online (facsimile) of Rousseau’s Le Citoyen, ou Discours sur l’économie politique, 1765 edition: https://books.google.co.uk/books?id=9ClkAAAAcAAJ&pg=PA20
48 Denis Diderot, ‘Lettre à mon frère’, in his Collection complete des œuvres philosophiques, littéraires et dramatiques, London: 1773; Voltaire, Traité de Métaphysique (1735), ch. 9: ‘De la vertu et du vice’, in his Œuvres complètes, ed. Beaumarchais, ‘de l’imprimerie de la société littéraire typographique’, 1784, XXII, p. 70; Jean-Jacques Rousseau, Le Citoyen, ou Discours sur l’économie politique, Geneva: 1765, p. 20.
