Essay on the causes that may affect men’s minds and characters

Georges Benrekassa

1This work was published for the first time by Henri Barckhausen in the volume Mélanges inédits in 1892, but without reproducing the stricken passages which were reutilized in L’Esprit des lois(in the manuscript are these words in Montesquieu’s hand: “Placed in the Laws”) which are certainly important: it concerns chapter 2 of Book XIV, a large part of chapter 10, and an important paragraph from chapter 14. The manuscript has been carefully prepared in the hand of secretary E, therefore between 1734 and 1739. It is the basis of the constitution, well before the hypothetical influences of Arbuthnot and Espiard, of Montesquieu’s ideas about “climate”.

2Had Montesquieu envisaged a separate publication? Perhaps. He would have had, in any case, rather different reasons for giving it up than those which had made him effectively give up on publishing Réflexions sur la monarchie universelle. That essay, a term he uses rarely, but clearly attached to a philosophical tradition from Montaigne to Locke – an inquiry put to the test – is both the temporary outcome of a long personal reflection, and testimony to the importance of critical examination of contemporary investigations about causes and therefore the differentiations of talents and destinies of different peoples. It started early. We can observe connections between certain passages of the Essai and what remains today of the dissertation of 1717 on the Différence des génies [‘Difference of geniuses’] which one finds in Pensées (nos. 1191 and 1192, principally). Moreover, the debates provoked by the Du Bos’s Réflexions sur la poésie et la peinture over the causes of prosperity or decadence of the arts, which also concern other domains and curiosities of Montesquieu, had had, it seems to us, great importance. The most illuminating rapprochements that Guillaume Barrera was able to make (correspondence with Dortous de Mairan, physiologist doctors like Malpighi, Stahl, Boerhaave, but also philosophers like Malebranche or Locke) induce other reflections: the Essai is an important stage in Montesquieu’s advance towards a new order of knowledge, which goes beyond divisions in disciplinary domains.

3The work of 1735-1737, which bears the mark of a personal clarification more than a completion for publication, is in two quite distinct parts, devoted to physical causes and to moral causes. We can see in the first part what will be the basis of Books XIV-XVIII of L’Esprit des lois, and relates to the whole evolution of Montesquieu since the academic dissertations. The point is to go beyond the pure mechanical conception of the action of the climate by heat or cold. That will make it possible to conceive another mode of connection of the soul and material world, far beyond the limits of our body, a connection comparable to those experienced by the spider in the center of its web, according to the image well known to the Stoic philosophers. To the action of temperature on the changes in fibers are added that of winds, modifications of nourishment, of sucs [meat juices] – more material than were animal spirits – the manner of sleeping, sexual differences, etc. And when in part two the future friend or intellectual protector of Helvétius decides to place education in the foreground of “moral causes”, it is to show that it allows the development or maintenance of the potentialities of physical causes, including in education much more than we think of in a narrow sense, as was the case in Book IV of L’Esprit des lois. Furthermore, very early, multiple investigations on the modes of conjunction, of correlation or discordance between “physical causes” and “moral causes” come to the fore. How are we to understand that “often the physical cause [should need] the moral cause to act”? (Pensées, no. 811). The Essai, on this level, allows us to understand that, for Montesquieu, the debate on the relative importance and the correlation of moral and physical causes requires more investigation than those which are grouped around research of what is determining in the final analysis.

4The investigation, very open, and impossible to treat following the point of view which Lanson developed with respect to L’Esprit des lois (mastery of the “moral” starting from intelligence of the “physical”) shows that it is about something different from a “warehouse of ideas”, as has sometimes been suggested. It is more, and different, and that is what the endpoint of the second part shows clearly, it is a very important marker in the formation of what is for us like one of the two centers of gravity of Montesquieu’s thought, along with the conception of the principles of government: the notion of a “general spirit” in the process of formation since the Traité des devoirs of 1725, where it was present only as an adaptation of the notion of national spirit, of which a formulation closer to that of the Essai is found in Pensées no. 542: climate, “combination of laws, religion, mores and manners”, and air of the time and milieu. Here not only almost all the aspects which will be enumerated at the beginning of Book XIX enter into composition (with the notable exception of the “examples of past things” – traditions, and also conscience of a historical identity), but all is placed under the direction, so to speak, of a “general education”, which is more or less the principle permitting a society to reproduce itself, or prolong itself. At the same time, as Guillaume Barrera has quite rightly emphasized, what it put to the test [essai] is the notions that govern, in their relation, the forms and levels of causality: suitability and reciprocity. We approach the perhaps inaccessible horizon of a global, if not totalizing, conception of causality.


Edition: text established by Pierre Rétat, presented and annotated by Guillaume Barrera, OC, t. IX (Œuvres et écrits divers II), 2006.

Translations: “An Introduction to Montesquieu’s An Essay on the Causes that may affect men’s mind and characters” (trans., annotation with some cuts by Melvin Richter), Political Theory, May 1976.

Jean-Baptiste Du Bos, Réflexions critiques sur la poésie et la peinture, 1719 (Slatkine reprint of the 1770 edition, Geneva, 1982).

Robert Shackleton, “The Evolution of Montesquieu’s Theory of Climate”, Revue internationale de philosophie 33-34 (1955) p. 317-329.

Jean Ehrard, L’Idée de nature en France dans la première moitié du XVIIIe siècle, Paris: SEVPEN, 1963 (re-edition Albin Michel, 1994), chapter 11.

Catherine Volpilhac-Auger, “La dissertation sur la Différence des génies : essai de reconstitution”, Revue Montesquieu 4 (2000),

— “Sur quelques sources prétendues du livre XIV de L’Esprit des lois”, in OC, t. IV, p. 902-916, on line [].