Examining the question of the laws of nature within Montesquieu requires that one review the familiar arguments concerning what Montesquieu himself owes to the writers on natural law, the list of whom is sufficiently long: Spinoza, Hobbes, Descartes, Locke, “the atheists,” the “apriorists,” or indeed Newton.116 Putting aside these subtle inquiries, it seems to us possible to make a Newtonian Montesquieu through a means both shorter and more certain. There exists between a supposed minor essay by Montesquieu, “Essay Concerning the Natural Laws and the Distinction between Justice and Injustice,” and the ideas of Newton, such as they appeared in the essay, “Concerning Gravity and the Balance of Fluids,” such a close relationship that the two deserve to be treated as if resulting from a single hand. This is to say that defining the central idea of Newton is, in effect, equivalent to defining the basis of the reasonings of Montesquieu. But there, we run up against a problem: the essay by Montesquieu might not be his at all, at least if one clings to the judgment of the modern authors who are most listened to.117 Certainly, one finds within Montesquieu the same lesson in Book One of The Spirit of the Laws, where Montesquieu affirms that man is like all other natural bodies, “following the relations of mass and velocity.” Nevertheless, the affirmations of this book are less precise than those of the “Essay Concerning the Natural Laws,” and what is more, we do not encounter any reason to cling to the authority of the authors, since there exists otherwise the means to establish the paternity of Montesquieu for this essay. Thus, we offer here a summary sketch of the Newtonian principle from which Montesquieu has derived a republicanism completely modern although natural. Following that, we define the general principle governing the origins and the end of societies, and finally, we explain how one arrives at attributing with probability the “Essay” and its ideas to Montesquieu.

Newton rejected Descartes's idea of one simple, mechanical motion, where self-movement was an illusion and the philosophical motion nothing more than a transfer or exchange of bodies, one for one. Moreover, he rejected the idea that space and extension are the same thing, which the res extensa assumes.