1Diderot’s admiration for Montesquieu’s genius and personality is generally praised, and we can only recall the evocation in the article “Eclecticism” in the Encyclopédie, written “11 February 1755 on returning from the funeral of one of our greatest men”. Naturally, Diderot emphasizes the “persecutions” borne by Montesquieu following the publication of L’Esprit des lois: he is also aware of the harassment by Jesuit confessors on his death. Much later, in the Lettre apologétique de l’abbé Raynal à M. Grimm, he would enumerate the persecutors of the genius: “tyrants, priests, ministers, and publicans”, perhaps dramatizing somewhat. From that to the epigraph he he thinks he can take from the Æneid for L’Esprit des lois (VI, 692, “Alto quæsivit cælo lucem, ingemuitque reperta” [‘[He] sought light in the highest heavens, and groaned when he had found it’]). But in Virgil it was about the dying Dido…
2This presence of Montesquieu in the heart of the most important article, perhaps, for defining Diderot’s philosophical inspiration, nevertheless has another importance. Montesquieu for him is indeed a “capital contemporary”, to use Gide’s felicitous terminology. The “eclectic”, according to Diderot, is the man who “dares think for himself”, and fashions an “individual, domestic philosophy”, based on critical examination, which gives him the faculty “of teaching the truth more than knowing it”; and it is certain that Montesquieu is for Diderot what he calls an “eclectic of genius”, one who “labors to compare known truths amongst themselves and combine given facts”. That said, there could be no question, from Montesquieu to Diderot, of a close relationship of inspiration or “influence”. There is a critical relationship, in constant evolution, of which the essential points should be noted. It follows a rather clear general line: Diderot in the long run came to agree with Montesquieu’s thought on certain decisive points, and this very important ultimate encounter is more worthy of consideration than many ordinary borrowings.
3Never did Diderot envisage L’Esprit des lois as a sort of reference “system”. He even came, in this regard, to prefer for a time (but only for a time) Lemercier de La Rivière and his massive work, L’Ordre naturel et essentiel des sociétés politiques, of which the answer-to-everything side, peremptory prescriber of saving principles, seemed really decisive. He would write to Damilaville in July 1767: “This book gave me more pleasure, and was a hundred times more useful than L’Esprit des lois. But it was only for a moment.
4During the elaboration of the Encyclopédie, the “informative” character of L’Esprit des lois is evident for Diderot as for many others: but one can appreciate the much more rigorous character of his reading by looking, for example, at the article “Argent” [‘Silver’] or his addition to “Aristocratie”. But the question is evidently that of the importance of L’Esprit des lois in the formation and the evolution of his political thought up to the journey to Russia. Should we propose in principle, with Jacques Proust, that Montesquieu was not one of Diderot’s initiators in the domain of political philosophy, because as Rousseau will say, he thinks his object is at first only positive law? The judgment requires nuancing, although it is in general justified.
5The fact that at the period of the Encyclopédie Diderot’s conceptions concerning the contract, right to resistance, and sovereignty are far from Montesquieu’s, as evidenced by the article “Autorité politique”, is obvious. And one must be prudent in speaking of possible “rapprochements”. We can have recourse to “Besoin” [‘Need’] to support a judgment of book I of L’Esprit des lois on Hobbes and the state of war: men “lose in societies the sense of their weakness and the state of war begins”. But we cannot go wrong by overvaluing encounters on the commonplaces of the rationalist century, often derived from Grotius and Pufendorf. There are many occasional borrowings of polemical import, in particular where the most “asocial” aspects of Catholicism are concerned, as in the article “Bonze”; without neglecting that the article “Célibat” [‘Celibacy’] draws its force from a fairly complete assimilation of books XXIII and XXIV of L’Esprit des lois: celibacy is but an historical accident, maintained with great difficulty; and the idea of forbidding monastic celibacy by law must not be excluded. It would doubtless be profitable to go to points of view that are consciously, explicitly divergent to see a deeper critical relation take shape, linked to precise analyses of French society: the article “Hôpital” testifies to an economic and social inspiration analogous to that of the famous chapter 29 of book XXIII of L’Esprit des lois, but it abandons the reference to obligations of assistance proper to the monarchy; the long addition to the article “Charge” by Boucher d’Argis shows that Diderot was able to understand the logic of Montesquieu’s point of view in book V, while pointing out the necessity of not letting society get mired in the system’s inertia.
6In fact the most interesting problem would be posed later. The best evidence of the type showing impact of Montesquieu’s thought on the endless elaboration of Diderot’s may be in the Observations sur le Nakaz, a first version of which he elaborated during his long pause in Holland, between March and September 1774, on his way back from St. Petersburg. This is an encounter on the level of profound political inspiration, and a very particular actualization of the central principles of Montesquieu’s political thought. For the work of the commission which she had constituted to elaborate a new Russian legislation (a new code, nakaz), Catherine had clearly designated a reference and a guide: L’Esprit des lois, which she had read and annotated for her use. The interest of the Observations is twofold. It holds to the ways of limiting of power, in this instance and more precisely the possible return from an absolute power very similar to despotism towards a limited power based on law that runs the risk of being frustrated by a certain “modernity”. Furthermore, the complex confrontation between the inspiration taken from L’Esprit des lois, what Diderot had been able to learn about the state of Russia, and other political models which have played an important role is capital: in particular his final assessment of the thought of economists based on the examination of a text of Le Trosne, which is a commentary of the Nakaz from a physiocratic point of view; the manuscript of this text which served as a starting point for Diderot’s work is written in the name of the “obvious”, of which the autocrat could again better impose the advent through her legal code.
7Diderot had long had misgivings about the reference to English freedom. He categorically rejected the idea of benefits from the diversification of feudal government. But the question of power is twofold and single at the same time, as for Montesquieu: it is that of its limitation, intimately linked to the play of social forces on which it can be based and their mode of efficacity. Diderot’s reading is very contemporary, and very foreign to purely constitutional views. To be sure, there must be institutional counter-powers, and here we find Diderot vaunting the “English constitution” against the timidity of the commission: “What they argue against the physical counterforces of a political body, keeping watch over the sovereign authority, seems to me flimsy, as evidenced by the English parliament, which appears to me an awesome counterforce to the king’s power” (title XII/6, p. 359). And he goes even further: “It would thus be salutary to fix the rights of the intermediary powers and fix them in an irrevocable manner for the legislator himself and his successors; if they are dependent on the supreme power, they are nothing.” (title XIII, p. 361). Catherine II took this very badly: she was much in favor of “subordinate and dependent” powers, according to the prudent final correction of Book II of L’Esprit des lois.
8The social realization of counterforces, according to Diderot, can obviously not correspond to the equilibrium which Montesquieu deems necessary to make power have to “halt its force”. But his Russian program (creating a powerful merchant class, and a third estate that can generate elites in the second generation) derives in fact from the same fundamental political philosophy. This Diderot, opposed to legal despotism and, more generally, to enslavement necessarily linked to the arbitrary, even to a provisionally beneficent arbitrary, is far from the physiocrates. “Every arbitrary government is bad; I do not except the arbitrary government of a good, firm, just and enlightened master. That master accustoms people to respect and cherish a master, whoever he may be.” (Entretiens avec Catherine II, Œuvres complètes, Club français du livre, 1971, R. Lewinter ed., p. 643, n⁰24).
Diderot, Observations sur l’instruction de sa majesté impériale aux députés pour la confection des lois (Observations sur le Nakaz), in Œuvres complètes, Paul Vernière ed., Paris: Garnier, 1963.
Sergio Cotta, “Illuminismo e scienza politica: Montesquieu, Diderot e Caterina II”, Quaderni di cultura e storia sociale, 1954, p. 338-354.
Jacques Proust, Diderot et l’Encyclopédie (1962), reissue Paris: Albin Michel, 1995.
Georges Dulac, “Pour reconsidérer l’histoire des Observations sur le Nakaz”, Oxford: Voltaire Foundation, SVEC 254 (1988), p. 467-514.
Jean-Christophe Rebejkow, “Diderot lecteur de L’Esprit des lois de Montesquieu dans les Observations sur le Nakaz”, Oxford: Voltaire Foundation, SVEC 319 (1994), p. 295-312.
Jean Ehrard, “Diderot lecteur de Montesquieu”, in Mélanges Robert Mauzi, Champion, “Varia”, 1998; re-issued under the title “La piété filiale” in Jean Ehrard, L’Esprit des mots. Montesquieu en lui-même et parmi les siens, Geneva: Droz, 1998, p. 277-293.
Laurent Versini, “Aphorisme et ironie: l’exemple de Diderot et de Montesquieu”, in Configurazioni dell’aforisma (Ricerce sulla ecritura aforistica diretta da Corrado Rosso 3), Carminella Biondi, Carla Pellandra, Elena Pessini ed., Bologne: CLUEB, 2000.
Muriel Brot, “Montesquieu dans l’Histoire des deux Indes”, dans Débats et polémiques autour de L’Esprit des lois, C. Volpilhac-Auger ed., Revue française d’histoire des idées politiques 35 (2012), https://www.cairn.info/revue-francaise-d-histoire-des-idees-politiques1-2012-1-page-123.htm.