Clinamen is the name Lucretius gave to the spontaneous microscopic swerving of atoms from a vertical path as they fall. According to Lucretius, there would be no contact between atoms without the clinamen; and so, “No collision would take place and no impact of atom upon atom would be created. Thus nature would never have created anything.” This was first described in Epicurean physics.

The clinamen has been taken up in discussions of determinism as a possible explanation for an incompatibilist free will.

The term has also been taken up by Harold Bloom to describe the inclinations of writers to “swerve” from the influence of their predecessors; it is the first of his “Ratios of Revision” as described in The Anxiety of Influence.

In Difference and Repetition, Gilles Deleuze employs the term in his description of multiplicities, pointing to the observation at the heart of the theory of clinamen that “it is indeed essential that atoms be related to other atoms” (184). Though atoms affected by clinamen engage each other in a relationship of reciprocal supposition, Deleuze rejects this version of multiplicity, both because the atoms are too independent, and because the multiplicity is “spatio-temporal” rather than internal.

In “Introduction to Civil War” [1], the French collective Tiqqun claims that “each body is affected by its form-of-life as if by a clinamen; a penchant; a leaning; an attraction; a taste. What a body leans towards also leans towards it; this goes for each and every situation: all inclinations are reciprocal.”

In the words of Deleuze and Guattari, “the clinamen is the smallest angle by which an atom deviates from a straight path.” The concept was invented by the ancient roman poet and philosopher Lucretius, whom Michel Serres places in that “orphan line of thinkers” that constitutes minor science (ATP, 398). Lucretius wrote (On the nature of things, Book 2, Lines 216-225):

The atoms, as their own weight bears them downPlumb through the void, at scarce determined times,In scarce determined places, from their courseDecline a little—call it, so to speak,Mere changed trend. For were it not their wontThuswise to swerve, down would they fall, each one,Like drops of rain, through the unbottomed void;And then collisions never could be nor blowsAmong the primal elements; and thusNature would never have created aught.

In Difference and Repetition Gilles Deleuze points out that it is important not to understand the “swerve” as a deviation from a preset path (difference as a negation), nor as a transcendent idea of “freedom” from such a preset path, but as pure and productive

difference-in-itself: “the clinamen is by no means a change of direction in the movement of an atom, much less an indetermination testifying to the existence of a physical freedom. It is the original determination of the direction of movement, the synthesis of movement and its direction which relates one atom to another” (DR, 232).

Clinamen in chaos theory“The clinamen, this spontaneous, unpredictable deviation, has often been criticised as one of the main weaknesses of Lucretian physics, as being something introduced ad hoc. In fact, the contrary is true—the clinamen attempts to explain events such as laminar flow ceasing to be stable and spontaneously turning into turbulent flow. Today hydrodynamic experts test the stability of fluid flow by introducing a perturbation that expresses the effect of molecular disorder added to the average flow. We are not so far from the clinamen of Lucretius!

For a long time turbulence was identified with disorder or noise. Today we know that this is not the case. Indeed, while turbulent motion appears as irregular or chaotic on the macroscopic scale, it is, on the contrary, highly organised in the microscopic scale. The multiple space and time scales involved in turbulence correspond to the coherent behaviour of millions and millions of molecules. Viewed in this way, the transition from laminar flow to turbulence is a process of self-organisation. Part of the energy of the system, which in laminar flow was in the thermal motion of the molecules, is being transferred to macroscopic organised motion” (Ilya Prigogine and Isabelle Stengers, Order Out of Chaos, 141).

Clinamen elsewhere in philosophy“Still, one cannot make a world with simple atoms. There has to be a clinamen. There has to be an inclination or an inclining from one toward the other, of one by the other, or from one to the other. Community is at least the clinamen of the “individual.” Yet, there is no theory, ethics, politics, or metaphysics of the individual that is capable of envisaging this clinamen, this declination or decline of the individual within community. Neither “Personalism” nor Sartre ever managed to do anything more than coat the most classical individual-subject with a moral or sociological paste: they never inclined it, outside itself, over that edge that opens up its being-in-common.” (French philosopher Jean-Luc Nancy, The Inoperative Community [La communauté désœu-vrée], 3-4).