Denis Casabianca

1The importance of this notion (Todorov, p. 396) is said to come from the role which Montesquieu assigns in the apparatus that presents the framework in which his study of laws is inscribed, at the end of the first book of L’Esprit des lois. Putting forward congruity (convenance, ‘conformity’) rather than the idea of causality (Goldschmidt, p. 53) leads to seeing the author’s design less as a “scientific” project than as a questioning of the means of producing adapted legislations. We find this idea of congruity in theological studies or in the approach of philosophers of natural law, like Grotius or Pufendorf, who use Stoic sources. We must examine how Montesquieu situates himself with respect to these traditions to separate out the particular usage he makes of it.

2We might expect to find the idea of congruity in the first two chapters of the first book of L’Esprit des lois, since we find there forms of discourse (scale of beings, state of nature) which traditionally mobilise this notion. But in fact that is not so, a sign that Montesquieu is moving away from the paths which he recalls by making use of a common vocabulary. The cosmological framework of the first chapter and the appeal to a “primitive reason” do not lead to an investigation of the overall order of created things. Montesquieu does not appeal to a principle of sufficient reason, like Leibniz, he does not direct attention to relations of “perfection”, like Malebranche, even though he defines laws as relations. Neither does Montesquieu take up again in this chapter his definition of justice as a “relation of congruity” (LP, [‣]), of Malebranchist inspiration (Assoun, p. 173-175), which he opposed to the idea of convention in order to counter the philosophy of Hobbes. Likewise, in the second chapter, which seems be taking the path of natural law proponents, the hypothesis of the state of nature is indeed explicitly opposed to Hobbes, but it does not lead to the systematic exposition of a natural law, in which the principle of congruity would make it possible to formulate natural laws on the basis of the reasonable and social nature of man; in that he sets himself apart from his predecessors (Grotius, De jure belli ac pacis, trans. Barbeyrac I, 1, §10 [Catalogue, no. [‣]: De jure belli et pacis, Amsterdam, 1646]; Pufendorf, Le Droit de la nature et des gens, trans. Barbeyrac [Catalogue, no. [‣]], I, 6, § 18).

3The notion of congruity appears in I, 3 to present the study of positive laws: it makes explicit the problematic of the government “most in congruity with nature” and commits to an examination of the spirit of law understood as an ensemble of relations. It is because the government the most in congruity with nature is “the one of which the particular disposition conforms best to the disposition of the people for which it was established” (“celui dont la disposition particulière se rapporte mieux à la disposition du peuple pour lequel il est établi”) that positive laws “must be so specific to the people for which they are made that it is a very great coincidence if those of one nation can be in congruity with another” (“doivent être tellement propres au peuple pour lequel elles sont faites, que c’est un très grand hasard si celles d’une nation peuvent convenir à une autre”, EL, I, 3; italics added, as in all quotations in this article). The congruity with the people for whom the laws are made is illuminated by the way these laws relate to the physicality of the country, climate, etc. Here congruity to nature no longer signifies agreement with the principles of natural law, but an adaptation to mores and circumstances. However, a relativistic approach to positive laws exists in the natural law tradition (in Gravina, whom Montesquieu cites, or in Pufendorf, De jure naturae et gentium, VII, 5, § 10), and it no longer suffices to oppose a “theoretical” perspective (which would pose the question of congruity from the point of view of natural law or primitive reason) to an “historical” perspective (which would pose the question of congruity by referring to the historical situation of nations). If Montesquieu does not intend to mesh the study of positive laws in history into a natural law foundation, it remains to be seen how his attention to situations bears in itself a normative requirement – without which it would fall into skeptical relativism, which would aim only at a juridical pragmatism or a concern for political efficacy.

4The relativism implied by the idea of relation and the principle of congruity does not plunge into undistinguishability all laws and all forms of government. Montesquieu “examines those [laws] that conform the best to society, and to each society” (Défense de L’Esprit des lois, part two, “General idea”, OC, t. VII, p. 87). Local congruity (“to each society”), which assumes the spirit of law, does not recast doubt on the existence of universal requirements, which should fill any legislation (what is in congruity “with society”). Nevertheless these requirements relative to all of humanity alone do not suffice to determine positively what form the government ought to take, even if they allow one to invalidate the despotic form. And if sociability is the effective desire to live together, from which derive the feeling of obligation and the happiness of being a citizen (EL, Preface), then it must be recognized that it is never given abstractly, but is necessarily actualized in a particular situation where it makes sense for the citizens. When it is a matter of condemning terrible laws or practices, the requirements common to all peoples make themselves felt, provided one is not blinded by prejudices, and that our second, social nature does not cause us to forget our nature as men. A universal norm that recalls the unity of humanity marks a limit to the diversity of institutions, even if they can be explained through an examination of the situations. This “negative” norm (Larrère, p. 28-34) shows clearly the distance between a simple internal coherence of the institutions and practices, where congruity would offer only a functional point of view, and a true goodness of the laws. For example, when Montesquieu considers torture as a political institution: “I was going to say that it could conform to despotic governments, where anything that inspires fear figures among the government’s motivations […]. But I hear the voice of nature crying out against me.” (“J’allais dire qu’elle pourrait convenir dans les gouvernements despotiques, où tout ce qui inspire la crainte entre plus dans les ressorts du gouvernement [...] Mais j’entends la voix de la nature qui crie contre moi.”, EL, VI, 17). The cry of nature is heard and silences the sufficient reasons evoked. It is within these limits that the legislative intention must be exercised in view of the better, according to the principle of congruity articulated by Solon (EL, XIX, 21).

5A whole vocabulary that echoes congruity served to guide legislative practice. The study of laws supposes an activity of linkage, of putting into relation, in order to grasp how “everything is extremely interconnected” (EL, XIX, 15). The vocabulary of “congruity” and of what is “in character” [propre] indicates a harmony of the various aspects examined. This adaptation can be understood as the result of a long process, as a certain religious practice adapts to a certain form of government (EL, XXIV, 5), but it can also refer to the work of the legislator. Error in the elaboration of laws can then be understood as discordance; Montesquieu speaks of contradiction (EL, XXII, 14) or contrariety (EL, XIII, 8). Likewise the verb shock, most utilized, indicates an incompatibility relative to the internal coherence that characterizes the organization of a whole (EL, V, 16). If it touches the principle of the government or the general spirit, it can represent a fatal shock insofar as the equilibrium of the whole is threatened; then “all is lost”. The ability of the institutions to last a long time despite partial or local incongruities is the sign of a dynamic adaptation. The verbs suffer, bear, tolerate are used to indicate a marginal congruity, a threshold beyond which the terms of the relations reverse. This capacity has to do with the characteristic flexibility of moderate regimes, which Montesquieu opposes to the rigid mechanics of despotism. In moderate governments harmony of nature, the principle of government and the laws is to mobilize the legislator’s effort; this harmony is always subject to renewal, but in return it favors legislative action by broadening the range of options. It is at once the result of the legislator’s action and the condition of all good legislation. It is aimed at and determines every specific prescription. That is why we can say that the use of the imperative in L’Esprit des lois seems often an imperative of congruity (EL, III, 11) that attracts the legislator’s attention to the means of realizing that harmony in situ (“How the laws must relate to the principle of government in the aristocracy” (“Comment les lois doivent se rapporter au principe du gouvernement dans l’aristocratie”), EL, V, 8). The disadvantages encountered most often designate a local incongruity which it is possible to correct, or which can be tolerated; their evaluation supposes knowledge of the “nuances” (Défense de L’Esprit des lois, part 2, “General notion”, OC, t. VII, p. 87). But the term also serves to qualify the supreme danger for he who labors to give laws that suit: that of falling into despotism (EL, VIII, 8).


Paul-Laurent Assoun, “Les sources philosophiques du concept de loi dans L’Esprit des lois: Montesquieu et le malebranchisme”, Montesquieu, De l’Esprit des lois, la nature et la loi (collective), Paris: Éditions Ellipse-Marketing, 1987, p. 169-179.

V. Goldschmidt, introduction to Montesquieu, De l’esprit des lois, in Écrits, t. II, Paris: Vrin, 1984 [introduction to L’Esprit des lois, Flammarion, GF, 1979, p. 11-57].

Catherine Larrère, Actualité de Montesquieu, Paris: Presses de sciences po, 1999.

Tzvetan Todorov, “Montesquieu”, in Histoire de la philosophie politique, A. Renaut ed., t. II, Paris: Calmann-Lévy, 1999, p. 384-408.

Denis de Casabianca, Montesquieu. De l’étude des sciences à l’esprit des lois, Paris: Champion, 2008.