Voltaire, to whom it was attributed by some, said to d'Alembert, "Il y a plus que du bon sens dans ce livre, il est terrible. S'il sort de la boutique du Système de la Nature, l'auteur s'est bien perfectionné." D'Alembert answered: "Je pense comme vous sur le Bon-sens qui me paraît un bien plus terrible livre que le Système de la Nature." These remarks were inscribed by Thomas Jefferson on the title page of his copy of Bon-sens. The book has gone through several editions in the United States and was sold at a popular price. The German translation was published in Baltimore on the basis of a copy found in a second-hand book store in New Orleans. The most serious work written against it is a long and carefully written treatise against materialism by an Italian monk, Gardini, entitled L'anima umana e sue proprietà dedotte da soli principi de ragione, dal P. lettore D. Antonmaria Gardini, monaco camaldalese, contro i materialisti e specialmente contro l'opera intitulata, le Bon-Sens, ou Idées Naturelles opposées aux idées Surnaturelles. In Padova MDCCLXXXI Nella stamperia del Seminario. Appresso Giovanni Manfré, Con Licenza de Superiori e Privilegio (8vo, p. xx + 284).
14. In 1773 Holbach published his Recherches sur les Miracles, a much more sober work than his previous writings on religion. In this book he raises the well known difficulties with belief in miracles and brings a great deal of real learning and logic to bear on the question. The entire work is in a reasonable and philosophic spirit. His conclusion is that "une vraie religion doit avoir au défaut de bonnes raisons, des preuves sensibles, capables de faire impression sur tout ceux qui la cherchent de bonne foi. Ce ne sont pas les miracles." The same year he published two serious but somewhat tiresome works on politics.
15. La politique naturelle.
16. Système social in which he attempts to reduce government to the naturalistic principles which were the basis of his entire philosophy. The first is also attributed to Malesherbes. There is a long and keen criticism of the Système Social by Mme. d'Epinay in a letter to Abbé Galiani Jan. 12, 1773 (Gal. Corresp., Vol. II, p. 167).
But the most interesting reaction upon it was that of the Abbé Richard who criticized it from point of view of the divine right of kings in his long and tiresome work entitled La Défense de la religion, de la morale, de la vertu, de la politique et de la société, dans la réfutation des ouvrages qui ont pour titre, l'un Système Social etc. Vautre La Politique Naturelle par le R. P. Ch. L. Richard, Professeur de Théologie, etc., Paris, Moulard, 1775.
In a preface of forty-seven pages the fears of the conservative old Abbé are well expressed. The aim of these modern philosophers who are poisoning public opinion by their writings is to "démolir avec l'antique édifice de la religion chrétienne, celui des moeurs, de la vertu, de la saine politique etc. rompre tous les canaux de communication entre la terre et le ciel, bannir, exterminer du monde le Dieu qui le tira du néant, y introduire l'impiété la plus complète, la licence la plus consomnée, l'anarchie la plus entière, la confusion la plus horrible."
17. Holbach's next work, Ethocratie ou Gouvernement fondé sur la Morale, Amsterdam, Rey, 1776, is interesting mainly for its unfortunate dedication and peroration, inscribed to Louis XVI, who was hailed therein as a long expected Messiah.
18. Holbach's last works dealt exclusively with morals. They are La morale universelle ou les devoirs de l'homme fondés sur la nature, Amsterdam, 1771, and
19. A posthumous work, Elements de la Morale universelle, ou catechisme de la nature, Paris, 1790. This is a beautiful little book. It is simple and clear to the last degree. There have been several translations in Spanish for the purposes of elementary education in morals in the public schools. It was composed in 1765. Holbach's attitude towards morals is indicated by his Avertissement—"La morale est une science dont les principes sont susceptibles d'une démonstration aussi claire et aussi rigoureuse que ceux du calcul et de la géometrie."