4Rhythms of Snow

Figures of Differentiation in Descartes’s Meteorology

Cecilia Sjöholm

Shapes of an Ontology

On February 4, 1635, Descartes writes, I walked on the streets of Amsterdam and observed first the formation of the evening frost and then the fall of hail. The last particles had “six tiny teeth,” like “wheels of clocks,” “very white, like sugar, whereas the grains, which seemed to be of transparent ice, seemed to be nearly black.”¹ He walks out again the next morning and observes, to his great astonishment, a kind of snow “of which I have never heard anyone speak”: it is “composed of small blades . . . completely flat, highly polished and very transparent.”² He spends days observing—and indulging in—a severe storm that shifts between snow and hail, marveling at the infinite variety of size, formation, and shape of the blizzard, speculating on its relation to clouds, winds, and temperature and on the origin and regularity of the patterns.

Meteorology (Les Météores) was published as one of three essays in Discourse on Method in 1637. It has received relatively little attention. But in times of climate change and dramatic shifts of weather, its grappling with atmospheric phenomena such as wind, rain, snow, light, and minerals, its mode of experimenting and writing is reactualized. It is not merely a testimony to Descartes’s investment in and fascination with nature—accounted for in graphic details of landscapes and environments.³ It is also a testimony to the limits of philosophy. Many have read the essays in Discourse as attempts to put the doctrines in the method of deduction to the test. But Meteorology belies the possibility of finding the cause behind phenomena that are as diverse in their expression as they are beguiling to the senses. Human subjects cannot master the elements or predict the weather, Descartes tells us.⁴ It hits us, and we are subject to its vicissitudes. While offering a key to the composites of nature, it also impels the limits of reason.

In times of climate crisis and unpredictable variations in weather conditions, not least the climate of the North, Descartes’s treatise, written during the Little Ice Age, has never been more significant. The kind of transformations that a northern climate materializes is given form through bodies of extension: small particles changing shape and movement, intertwining, interfering, and reorganizing. The treatise, which renews the Aristotelian tradition of writings on meteorology understood as the predilections of earth and water, does not only present us with hypotheses of nature’s smallest building blocks. It offers a materialist vision of ontological dignity: the discourses on vapors, exhalations, winds, and clouds construe an aquatic world, consisting of water in different shapes, the particles of which are only partly visible. The discourses on snow, rain, and hail analyze drops in temperature dramatic enough to cause distinct shifts in size, movement, and organization. This universe is, by Descartes, considered as full: there are no gaps, although there are transformations: Cartesian ontology is concerned with the nature of these transformations, their cause, their variety, their physical dignity.

In the early prints of the book, the text is accompanied by images of the formations of snow and hail depicted in detail. The sensorial particularity of the formations, together with their figural transposition, is enough material for a heightened understanding of how the weather of the North is formed, exposing men to elements that they cannot control. The variation and transformation of frozen particles and the relation between all the elements that create them point to such a complexity that Descartes draws the conclusion that the weather cannot accurately be predicted by men. Not only the wondrous but also the violent character of phenomena of nature bring men to the brink of what they may even be able to imagine. Clouds may form materials that seem like milk or blood or flesh, and even engender “certain small animals”; therefore, we may have rains of iron, blood, or locusts.⁵

These images are not illustrations. They are thought-images, philosophical approximations of a preconceptual dimension of experience that abstract language fails to seize. In this way, they point to a dimension in Descartes’s philosophy that has been little commented upon, the use of aesthetic means to capture a dimension that lies between the res extensa and the res cogitans. The use of aesthetic figures is a methodology explicitly appreciated by Descartes, as developed in Rules for the Direction of the Mind. Figures do more than illustrate the text; they are productive of the ontological notion of an infinite universe that is posited in the shape of minute particles. This offers a key to Descartes’s Meteorology. Here, Descartes relies on rhythmic figurations in image and narrative that bring them to the limit of reason. Descartes posits a full universe of an infinite variety of aquatic shapes that move and transform in a way that we can never fully predict. The treatise does not construe rhythmic figurations as illustrations of what it says. Rather, it relies on a rhythmic conception of the “shapes, sizes and motions” of atmospheric phenomena.

This chapter is not concerned with situating Meteorology within Cartesian natural philosophy or an assessment of his method of deduction. The aim is rather to bring this work into a contemporary horizon of inquiries where shapes, or “figures,” can be negotiated as philosophical thought-images of differentiation and production of differences. Descartes approaches the atmosphere as an aesthetic kind of organization, like music or painting. In this conception, rhythm is a descriptor transgressing the division between a metaphysical notion of the infinite and the sensual experience of atmospheric matter. This aesthetic dimension of the treatise, defined as a mode of encountering and reflecting on atmospheric phenomena through senses, emotions, and intellect, characterized by an open involvement with worldly experiences, is an integral aspect of the text. Meteorology is not only based on observation and experiment but also on narrative and figures.⁶

There is an affinity between the repetition of lines in Descartes and abstract painting and drawing: a visual experience of a rhythmicality in the extension of space, and of matter. It can be experienced, perhaps, through the body, but this does not mean that it refers to the body. Rather, it strives to move outside of it, to depict the very line between embodied experience and the physical movement that lies beyond. It carries us over to what we cannot perceive: the dimension of volume, of geometry, dimensions that are irreducible to anthropomorphic conceptions.

The reason why Cartesian natural philosophy has attracted newfound attention in recent years is perhaps that it flickers between the res cogitans and the res extensa, the subject of deduction and the fleeting character of matter and of bodies. Traditionally, it has been widely held that Descartes takes us to a point where we must choose between the certainty of reason and the flickering transformations of nature that are vaguely perceptible to the senses. As has been mentioned many times in this book, Cartesian dualism—or what is perceived as such—is routinely one of the most berated doctrines in contemporary thought.⁷ But Descartes’s natural philosophy is so varied and rich that it is hard to even identify a dualistic system.⁸ Rather than exemplifying a doctrinal metaphysics, Meteorology can be situated between Descartes’s metaphysical writings and his physics.⁹ The standard criticisms of Descartes’s dualism have now been supplemented with a new view on his natural philosophy and the varieties of antinomies that are being challenged there. Moreover, a complex philosophy of imagination is integral to the notion of understanding, putting the idea of certainty in a new light.¹⁰

Still, Meteorology is one of the least referenced texts. This is reason enough to read it anew. In this chapter, rather than treat Meteorology as a treatise that exemplifies a certain method of deduction developed in Discourse on Method, we will analyze its figurative approach to nature as a meaningful creation that does not translate into anthropomorphic ideas or concepts. Rather than engage in models of representation, Descartes’s hypotheses are concerned with the action on and between bodies in modes that can be described in terms such as affects, flows, and rhythm.

The Historical Background of the Images in Meteorology

Meteorology tells of an involvement with cold weather that speaks of great fascination. The weather of the North is valorized as meaningful and wondrous. It is perhaps Meteorology that gave rise to rumors circulating in the Nordic countries that he did not die in Stockholm at all; instead, he traveled to a Sami village in the north of Sweden to learn to play ceremonial drums.¹¹ The most intriguing aspects of Meteorology is the visual force with which he depicts snow, wind, and ice, using not only abstract reason to work out the “shapes, sizes and motions” of nature’s invisible components but also images.¹² Attempting to find “the causes of everything that is most admirable above the earth,”¹³ Meteorology is one of the treatises that most forcibly uses images to, paradoxically, bring out what we cannot perceive and to develop an iconography.¹⁴ Snow, wind, and other phenomena of nature are here transposed into complex particles rather than visualized as anthropomorphic reductions.

The treatise was supposed to have been included in a work of modern cosmology and technique: Le Monde, The World in 1633. However, for fear of being condemned as a heretic, Descartes withdrew the publication of Le Monde. Instead, Meteorology, together with his treatise on vision, optics, and geometry, appeared together with Discourse on Method in 1637. As mentioned, whether the essays are to be read together with Discourse is often debated, and not a line of questioning pursued in this chapter. What is at stake is rather the aesthetic vision, which has been kept between the earlier and the later project of publication. The aesthetic dimension, as a mode of encountering and reflecting on atmospheric phenomena through senses, emotions, and intellect, and characterized by an open engagement with worldly experiences, is an integral aspect of Meteorology. The treatise is based not only on observation and experiment but also on narrative and figures, a baroque aesthetics intertwined with scientific thought. The weather of the North, and the minerals and atmospheric phenomena that accompanies it, determines the hypotheses of nature’s smallest building blocks.¹⁵ Rhythmic figurations in image and narrative intersect with sensual experience; Descartes is positing a universe of an infinite variety of aquatic shapes that move and transform. This ontological version of a natural philosophy does not construe rhythmic figurations as illustrations of what it says. Rather, it relies on a rhythmic conception that is already inherent to the description of the experience of weather and other atmospheric phenomena that belong to it.

The figures, describing sensual appeal as well as the shock of sharp tastes, are not there solely to work out a possible model of a hypothesis. They must be seen in conjunction with the overall project described in Principles of Philosophy: How do we acquire knowledge of what we cannot see? Descartes’s natural philosophy departs from the shapes, sizes, and motions he believes he can demonstrate by using mathematics.¹⁶ But the letters also make clear that the images are not merely mathematically construed diagrams. Nor are they allegories or mimetic depictions of facts. They are not immediate translations of things.¹⁷ Instead, the figures imply an infinite variety of differences in perceptible objects, giving an ontological status to the production of differences that challenges the subject of scientific knowledge through their unpredictability.

As Descartes conceives it, clouds and vapors are, in themselves, objects for poets and painters.¹⁸ They are extraordinary phenomena to be explored by the senses as well as understood by the mind. Alternating between the hot and the cold, the hard and the soft, between the soft winds on the shoreline and the storm over the oceans, little snowflakes and thunderous avalanches, the weather, and its transformations is a source of wonder, often mediated through Descartes’s own experiences—and sometimes through conjecture and scattered evidence.¹⁹ The treatise is concerned with finding causes. But phenomena such as weather, which envelopes us, has a sense in itself. We may explore it by thought. But we cannot find it by thought; it enwraps us.²⁰

Visualization was an explicit means to transmit the beauty that was not only the object of Meteorology but also at the origins of its conception: the colors of the rainbow, the perfectly proportioned stars of snow, and so on. In Meteorology, Descartes was closely involved in the making of the images. He engaged Frans van Schooten the younger, who was both a painter and a mathematician, a combination Descartes repeatedly advocated the importance of.²¹ Before the publication of the three essays in the discourse, Descartes wrote to his friend Marin Mersenne in March 1936 and explained that he was particularly concerned that the book would be beautiful—the paper and the font should be appealing. Beauty is a quality in its own right. This also applies to the images. In a tone of mocking humility, he expresses hope that Mersenne can perhaps explain to the engraver how his own poorly drawn figures are to be interpreted.²² Moreover, as he later writes to Mersenne, he has attempted to find the most beautiful examples of what he wants to demonstrate as the building blocks of nature. The book on Discourse and the three essays, Descartes explains to Mersenne, were to present a “universal science” addressing a lay audience, made in such a way that even novices could understand it.²³ It is the mind that sees and not the eye; an argument made in relation to painting both in Optics and in Discourse on Method, which were published together with Meteorology: the image of painting is used to figure how thought works, between light and shade, the visible and the invisible.²⁴

The concept of figures can be seen in this vein. In seventeenth-century France, the word figure had many uses, ranging from aesthetic to mathematical.²⁵ Figurae (Latin) carry a dimension that stretches from image, implying the subjective capacity of imagination—one figures things—and the more linear deductions of mathematics and mechanics. Descartes refers to his own sketches as figures. His images are crucial for his philosophy of nature because shapes, sizes, and motions are also mathematical.²⁶ “Figure” is also the concept of the often-referenced rule twelve in the Regulae Philosophicae, Rules for the Direction of the Mind, which Descartes began writing in the 1620s. It was published in 1684, after his death. The concept of “shape,” also, derives from figurae; it is “figure” in French.²⁷ But in Rules, it becomes clear that shape does not capture the meaning of figure. Nor does diagram, which some scholars have utilized.²⁸ Unlike geometrical lines, and the diagram, the figures in rule twelve have extension. They imply a spatial and embodied vision, a kind of flesh.

The question of how to interpret the notion of figure in the Rules has been an object of debate. This has often been construed through their uses in other writings. Dennis Sepper has placed Descartes figures in the realm between imagination and knowledge: they cannot be reduced to ideas or representations but refer both to some kind of sensible experience and beyond—“all figuration requires activity—the minimum of which is like conceiving figures mentally or sizing up an object in a glance.”²⁹ As German philosopher Sybille Krämer has argued, Descartes transforms geometry into a figurative “language of the eye,” which not only represents the objects but constitutes them; the objects arise through the operation.³⁰ In this way, the figure referred to in rule twelve, as has been shown by French philosopher Jean-Luc Marion, occupies a space between the res cogitans and the res extensa, if we are to read Descartes’s work while retroactively applying his own terminology. This gives the hypothetic character of the figure a certain status that is irreducible to both geometry and “psychology”; the figure is not knowledge inscribing itself in the world, Marion writes, but the world expanding in a uniform way before and under knowledge.³¹ Figures are ideas manifesting themselves as sensations, which may find their immediate support in the form of pain, cold, heat, and so on. These sensations are described through bodies. But what is particularly notable is the arbitrariness of the codification; things are figured that lack form in the outside world, such as colors.

Nothing is, as Descartes writes in the Rules, more readily perceptible by the senses than figure, for it can be touched as well as seen. By this, Descartes refers to the fact that figures are construed by a multiplicity of the senses. In the figure, we perceive not the real world but the phenomena. We perceive it not as an idea but as a thing in space and time, of proportions and dimensions that have weight and color, taste and the quality of touch, and so on. Figures are both sensual and intellectual; they arise between passive responses and intellectual elaboration and present themselves to the mind spontaneously, preconceptually but distinctly different from other things and phenomena. They are not “real” in the sense that they directly correspond to something manifest in the outside world. They are, however, caused by a sensual imprint; sense impressions are in themselves altered figures of their source, transmitted through rays of light or nerve endings in the body.³² Figures may have a variety of sources. They may be passive impressions or active elaborations of the mind. A figure may arise as we concentrate “our mind’s eye” on one thing in order to perceive the shapes of the world of extension.³³ A figure captures the extended body of the res cogitans: that which we reflect in our mind’s eye while we perceive it through our senses. A figure is not a representation but rather an abbreviated suggestion: “the more compact these are, the handier they are.”³⁴ For that reason, in an image, certain things can be exaggerated and other things left out. Responding to a critique, Descartes defends his choice to publish an image of a sheep’s brain rather than a human brain in Optics: certain parts, such as the ventricles, were depicted much bigger than in a human brain. But to Descartes, such a figure served much better to “make visible” what he had to say.

In the end, knowledge is the perception of nature’s composition in its simplicity.³⁵ In Geometry, the images are made up of lines.³⁶ The geometer knows well, Descartes writes, that lines have no breadth and surfaces no depth, yet he goes on to construct the one from the other. When figures are drawn and displayed, it is easier for us to understand surfaces and volumes, proportions and relations. Straight lines are also figures since they allow us to apprehend an extended object.³⁷ Mathematical figures, in this way, are mediated through a figural imagination of extension and forms—making Cartesian science not just an object of reason but also a baroque figural thought.³⁸ This method is used in Meteorology throughout. In Optics, geometrical and algebraic methods are applied that construe the hypotheses of vision, light, and atmosphere in the form of lines.

Meteorology deals “mainly with the nature of salt, the causes of wind and thunder, the figures of snow, the colors of the rainbow (where I also try to demonstrate the nature of each color) and the crowns, or halos, and suns or parhelia as those that were seen in Rome some six or seven years ago.”³⁹ The latter indicated that Descartes in fact never experienced this; but it was a common theme in early modern visual culture and indicated an omen of significant events. The very function of “halo,” the parhelia, was to Descartes immediately connected to “hyperbole”—that is, a geometrical figure, an example of how the transposition between Meteorology and Geometry was embedded in the notion of figure.⁴⁰ The final essay, Geometry, presents “a general method of solving all the problems that have never yet been solved”⁴¹—referencing the distinct use of figures as a source of deductive reasoning. However, the figures move beyond a consistent method of deduction.

The images in Descartes’s work have a variety of sources: some are copied from Descartes’s own manuscripts and are evidently drawn by Descartes himself. Some have been added in editions after Descartes’s death and have no relation to any original (e.g., Charles Le Brun’s famous faces in Passions of the Soul). Some images, and this includes the bulk of the images in Meteorology, are the result of Descartes’s personal engagement with editors and artists. The address to a wider audience is crucial, but so too is the philosophical impact. The pedagogical and philosophical aspect of the images, in turn, cannot be distinguished from their aesthetic elaboration—using images in his books, Descartes also distanced himself from Aristotelian metaphysics and engaged in new theories of perception that were brought into his work on mathematics and physics. The work of “artisans” contributed to the amalgam between figure and reason. Together, they stimulated the senses while interpreting movements and proportions in the outside world. To Descartes, perception relates to objects in the world in the same way that images relate to perception. Image and object are not the same, just as the perception of an image and an image are not the same. In both cases, an apprehension of the outside world is created through the qualities inherent to images: lines, movement, and suggestions of extension.⁴²

In Optics, Descartes describes the differentiation between perceptions and external objects. Perceptions are not identical to external objects; they are instead prepared in the brain as images. With this insight, Descartes ended the philosophical doctrine of simulacra (i.e., the idea that the world is planting images in us that resemble that which is outside, or that perception would be a natural mirror of the external world). It is the soul that sees and not the eye, a proposition that is made in accordance with the reflection on the perception of engraved images, pointing to the fact that we see more sides of an object in an image than are actually represented.⁴³

Descartes also worked with his publishers concerning the layout of the book,⁴⁴ and with Huygens in particular, there was much discussion about the figures. Descartes provided sketches (figures), and he was particular about their placement, measurement, and repetition. The images were supposed to be worked up in taille en bois (wooden print) by a craftsman or artist.⁴⁵ Again, it was crucial that the artist was also well versed in mathematics.⁴⁶ As we have seen in the discussion of Treatise on Music, mathematical figures were seamlessly interwoven with his philosophy. To Descartes, this provided a modern dimension to philosophical thought, which extended beyond the aesthetic experience of music. He considered the particular combination of mathematics and imagery as superior to scholastic reasoning more broadly, not least when it came to the understanding of natural phenomena: it is better to insert nature in philosophy than philosophy in nature.⁴⁷ As we have seen, this is done through the image: I believe that nothing can be imagined that cannot be solved by a line, as he writes to Beeckman.⁴⁸ Such lines belong to arithmetic and music, but also to the discourse on light and the atmosphere.⁴⁹ The wish for an artisan-mathematician applies not only to Geometry but to all three essays following Discourse on Method.

Descartes was particular with the choice of artist.⁵⁰ He mocks his attempts to be the “artisan” of his own books.⁵¹ The artists are neither to provide arithmetic diagrams nor mimetic images but to convincingly represent the differences between particles that are entangled with one another: water, fog, rain, and hail.⁵² This demand resonates both with the scientific hypotheses presented and the aquatic world produced by the text: to Descartes, the world is full of matter in different shapes and sizes, which is also what causes the transformations of atmosphere, weather, and climate.⁵³ The shape of a particle will determine the way in which it moves and how it is transformed, and its relation to other particles and their shape and the spaces between them. The notion that the universe is full, there is no vacuum, as well as the notion that the universe was without limits was subject to derision by Hobbes, because it could not be tested. Perhaps this would not have been a problem, had Descartes’s Principles as well as the essays launched metaphysical doctrines rather than hypotheses of natural philosophy.⁵⁴ But Descartes was only interested in using observation, imagination, and demonstration of different aspects of the ontological differentiation that he was exploring.⁵⁵ Accordingly, after the essays, Descartes had the intention of proving the existence of even smaller particles, inconceivable to the eye, that filled the spaces that the other particles left open.⁵⁶ The differentiation between particles is infinite; thus, the factors of shape, size, and movement affect the weather in such infinite variety that we end up not knowing the extent to which they can transpose, alternate, and metamorphose.

In Meteorology, as well as Optics, the images are produced to induce a process of cognition situated between the abstract and the sensual. In Optics, the images often reference themselves: a hand making the drawing may be placed in the engraving, for instance. In the early editions of Descartes’s natural philosophy, the same images would be repeated on several pages in a row in order to allow for the abstract apprehension of the text and the process of visualization simultaneously. This was done so that the reader would not, as Descartes’s friend Constantijn Huygens put it, have to err in the search for an image in the same way that “a bird attempts to encircle the tree he has left.”⁵⁷ In older editions of Le Monde (i.e., Les Méteóres, Dioptrique, and L’Homme, in the Shuyl edition from 1664 as well as the Opera Filosofica from 1656),⁵⁸ the same illustrations are used repeatedly, page after page. In this way, Descartes inserts the reflexive subject in the reading experience. The perception of images is intertwined with reflection of how perception is structured.⁵⁹ In the Shuyl edition of L’Homme, one can see the image of a person that has burned himself repeatedly. The person is “burning” from a fire that hits the nerve endings that run from the foot. Repetition is in itself, as German philosopher Edmund Husserl has shown, inherent to the perception of images as such. The image always has a dimension of phantom to it: I posit each mode of the appearance of an image as a mode of appearance of something that already has been. The engraving, which is inherently repeating the same through being printed and distributed in a number of volumes, is a mode of repetition that carries a phantom at each page. It is the carrier not so much of a corporeal memory as of a figment: an idea, a fluctuant piece of fantasy. Through their very repetition, however, the engravings acquire a reference. They are not representing a natural object but serve as what Husserl calls a recollective representation.⁶⁰ In the engravings, the body is mimicked as a physical entity. It is rather made out as a phantom, whose mode of being, in space and time, lies in the repetitive recurrence of the same physical sensation over and over again—in this way, the pictorial mode of the engraving corresponds to the very idea of how corporeal affects work.

Figure 4.1. L’Homme: Et un traitté de la formation du foetus, Paris, 1664, Royal Library Stockholm.

The image is repeated several pages in a row. In this way, the figures are not mere vehicles for the imagination, adding life to an abstract text. They construe a line between pain as “inner” corporeal experience and the perception of pain as an image of the mind. Descartes also worked with similar sketches in his letters; for instance, he addresses a friend explaining how experimenting with the flame of a candle made him meditate on the difference between inner and outer images. This is also what he attempted to achieve with the images of Meteorology—showing the difference between the structure of the weather and the way it is felt on a human body.⁶¹

The Senses of Meteorology

A multifaceted and flexible method of observation, including sensual experience and the capacity to be moved, is integral to Meteorology. It is this method that may be described as aesthetic; it is construed through the gathering of sensible information, which is then transposed into imagery. This method assumes that the experience of nature is meaningful in itself, sometimes made knowledgeable through arithmetic figures, but in the end irreducible to mathematics.

If we are to find the causes behind that which is the most “wondrous above the earth,” as stated in the introduction to Meteorology, we must begin our inquiries in a state of wonder.⁶² Wonder, in Passions, is defined as an affect that incites the production of new knowledge.⁶³ It is a passion of the soul, which means that it is not a physical reaction but rather intrinsically intertwined with intellectual elaboration. The knowledge produced by wonder takes place in a brain “where the organs of the senses are that contribute to this knowledge.”⁶⁴

Nature produces a marvel that sparks thought, we are told at the beginning of the treatise. Once we have understood the causes of weather, we no longer need to marvel at it.⁶⁵ Here, Descartes implies a separation between aesthetic experience, which sparks the emotion of wonder, and scientific knowledge, which provides answers to the questions that wonder helps raise. In every inquiry, there must be something unknown.⁶⁶ Once answers are provided, wonder is to be extinguished.⁶⁷ Critics have taken this to be a quaint goal of Cartesian Meteorology.⁶⁸ However, wonder is intrinsically interwoven with the Cartesian ontology of differentiation; it always comes anew. Observing and experimenting with the visible world, the weather, water, the rainbow, and the behavior of minerals in water, thought grapples with the expansion, contraction, agitation, and movement, the transformation and the intertwinements that take us from the visible to the invisible. Therefore, thought also engages with figures that lies between the sensual and the abstract, implicating an experience of “the sizes of the bodies we see, their shape, motion, position, duration, number and so on” as Descartes writes in Principles.⁶⁹ Thought can retract from sensual experience, but is also intertwined with it, through the passion of wonder. There is an intrinsic relation between the wonders of sensual experience—of the cold and the snow—and the wonders produced at the thought of the sublime cause of these experiences. The latter, however, is not to be found to the full: it is retracting from reason.

Shape is a primary category in Meteorology, which figures the world of water in the northern hemisphere: sea, rain, ice, salt, vapors, clouds, snow, hail. It is a full and infinite universe of differentiation and movement, intertwining, separating, and metamorphosing. The images are the result not only of observation but also of metaphor: the way in which a particle can be described in a rich pictorial language affects its geometrical figuration. Imagine, Descartes writes to his friend Henricus Reneri, “the air to be like wool” and the ether within to be like little whirlwinds.⁷⁰ Water is “like little eels.”⁷¹ Rain can appear like perfect rounded shapes, but also transform by air and weight. Rain can turn into vapor, and vapor, when it gets cold, transforms into various shapes of snow and ice. They can join like “slender fibres” or they can freeze like drops, forming “small knots or lumps of ice” with surfaces that are “velvety, or covered all around with hairs.”⁷² The particles are construed so that they can fit into different bodies, or shape-shift with one another.

The formation of clouds, the shift between winds, the formations of frosty landscapes, marshlands, and shorelines—all point toward the invisible dance of a full universe of differentiation. Its shape and movement and the size of its particles are brought forth in the images of the text as well as the wooden prints. The images are composed of a mix between particles and landscape, where the small, invisible particles are drawn above natural size, figuring components of volumes and proportions.⁷³ Some of the images gather several kinds of invisible components of different aspects of the atmosphere in different compartments of the image. Winds are figured in a certain way, vapor in another, water in a third manner. Its transformations, from water into vapor, comes from transitional effects of spinning and swirls, invisible energies creating movements that create an effect of inside-out; we are drawn into imperceptible centers of production. “I am following your advice on the figures,” Descartes writes to Huygens, “and place them in relation to the text, made in wooden print.”⁷⁴ The most difficult is, as you have seen, to “represent how the drops of water are disposed in the skies . . . and how they have extended into vapors that cause a wind as strong as a steam engine.” Here Descartes inserts distinct marks for strong winds, making visible how they affect the volumes of the atmosphere. It is also difficult to explain how drops of water “twist around the parts of salt in the sea,” which are, he explains, the latest images he has made. “I hope,” Descartes says, that when it comes to the flakes of snow, “winter will help.”⁷⁵

Causality is deeply intertwined with shape, and shape can be demonstrated in figures. “To see a world in a grain of sand,” William Blake wrote, and Descartes does precisely this in his discourse on salt.⁷⁶ This is a text in which we still have access to images produced by Descartes’s hand. It demonstrates that the senses, and a capacity to be astounded in front of natural phenomena, offer an access to the ontological differentiated universe. The world is meaningful in itself, and it is presented to us in aesthetic forms that we experience through our emotions, our senses, and our curiosity. The text does not isolate salt as a material substance; its spinning and swirling in the water puts to the test what the world is in terms of “rhythmic extension.”

Figure 4.2. Vapors, Les Météores. In Discours de la methode, Leyden, 1637, Royal Library Stockholm.

Figure 4.3. Snowflakes, Les Météores. In Discours de la methode, Leyden, 1637, Royal Library Stockholm.

The discourse on salt is accompanied by five little figures, four of which are evidently drawn by Descartes as reported by de La Forge.⁷⁷ We see little particles, rounded cylinders by approximation, accrue in bigger shapes after each step. Particles of salt have their own shape, Descartes writes, different from water, which is also what makes salt behave the way it does in relation to other bodies, to wind, to fire, to fluids. Salt has a penetrating quality; it preserves meat by entering it through small pores. Through such penetrations, it also helps create the refraction of light on the sea and the miracle of ice in the middle of the summer.⁷⁸ It also creates the taste of salt on the tongue, sharp needles penetrating the pores.⁷⁹

The miracle of crystallization becomes, in Descartes’s text, a result of the movement of particles, their gatherings and their splits, their coming together in the flakes that we today may serve as table salt and their dissolution in hot water. Salt water and fresh water swirl and twirl in rivers, seas, mists, and rain, above the skies or under the earth, moved by fire and heat or other particles. The crystals of salt are formed by much tinier particles that they eye cannot perceive, but we can perceive the behavior of the flakes, from the moment they come together until the moment they break, by heat, into powder, when their “tiny prisons” are broken. The flexible behavior of salt can be explained by the particles of water hosted in the flakes. The shape of water particles and salt have developed over time, Descartes argues; water has become pliant, bendable, and flexible. This affects the salt particles, which are hard like “cylinders or rods.”⁸⁰ These particles can also be corrupted and turn into acidic water, which has quite a different shape and agitates the nerves of the tongue differently.

“Sizes, shapes, positions and motions are my formal object (in philosophers’ jargon), and the physical objects which I explain are my material object,” Descartes explains in a letter to a friend. But as we can tell from the narrative above, empirical observations are ingrained by sensual data. From “the oblong and inflexible shape of the particles of salt, I deduced the square shape of its grains, and many other things which are obvious to the senses.” Observation is not enough; Descartes wants to “demonstrate the cause by the effects a posteriori.”⁸¹ The effects produced in nature that we may perceive, Descartes writes in Principles of Philosophy, “almost always depend on structures which are so minute that they completely elude our senses.”⁸² Observable effects have imperceptible causes, but shapes and formations construe preconceptual hypotheses of nature’s consistency.

Figure 4.4. Salt, Les Météores. In Discours de la methode, Leyden, 1637, Royal Library Stockholm.

Figure 4.5. Salt, Les Météores. In Discours de la methode, Leyden, 1637, Royal Library Stockholm.

The first figure of Descartes points to the line in which salt particles will move in hot water, the second to their loose floating around on the surface of the water, the third shows their gathering in regular patterns, and the fourth and fifth the consolidation and then loosening of that pattern. The patterns are made up of little cylinders properly counted in symmetry. The images have an obvious arithmetic and geometric dimension to them: they are in part figured through calculation. But the senses intertwine with the figural; water against the tongue gives a sense of fluidity like “little eels,” whereas the sharpness we experience on our tongue through the taste of salt leads to the hypothesis of hard cylinders. The particles are figured as an equal result of narrative and visual imagination, the pattern of crystallization and separation is conceived as an aesthetic experimentation involving sight, touch, and taste. In this way a full universe is posited where bodies are offered extension and movement.

Figures of Rhythm

Descartes’s “shape” does not mimic nature. But its status is not contingent. The images serve as scientific evidence in times of “cognitive pluralism.”⁸³ Meteorology and Optics provide thought-images that are a conglomerate of reason and imagination.⁸⁴ This means that are produced both out of reason and imagination—not one or the other, but both at the same time. They have, of course, some kind of illuminating function, but they are not illustrations.⁸⁵ This is not without its problems. Using images in this way has been called a form of “visual reductionism.”⁸⁶ But it is not certain that the figures of weather and salt are objects of deduction. They imply the existence of an infinite variety of movements and transformations, pushing beyond the limits of reason: the complex variety of particles supersedes the capacity to make futural predictions about their behavior.⁸⁷ Rather than being products of reason, the images and figures are conjectural images of understanding, of how the production of small particles behaves.

The weather, as well as atmospheric phenomena, is governed by formations that Descartes explicitly tells us we cannot control. Whereas Optics placed more emphasis on the relation between consciousness and perception, Meteorology puts the production of differences into focus. This can be seen in his account of the aquatic world of formations of snow, rain, hail, salt, and so on, but also in his account of colors. In Rules, Descartes makes the claim that colors, also, can be figured.⁸⁸ In his discourse on the rainbow in Meteorology, he does just that. Descartes picks up his pen to calculate, but also draws angles through which light is reflected in water.⁸⁹ Colors are produced by movement in the matter that hits the eye, interacting with light.⁹⁰ This hypothesis can be compared to the figures in Rules, where Descartes seeks to demonstrate the difference that makes colors, also, into figures or shapes. The abstract figures drawn there are not to be seen as geometrical translations of color but as a hypothetical demonstration of the difference between colors, suggesting that their variety is endless: “the infinite multiplicity of Figures is sufficient for the expression of all differences in perceptible things.”⁹¹ (See fig. 3.2.)

Figures, then, do not mimic objects, but neither are they abstractions or models. In rule twelve, they are presented as preconceptual gatherings in a universe of infinite possibilities. They actualize several senses, producing multi-dimensional forms in space and time: “we must think of the external shape of the sentient body as being really changed by the object in exactly the same way as the shape of the surface of the wax is altered by the seal.”⁹² Bodies have shapes that we may touch, and all our senses participate in their apprehension as figures; figures are, then, inherently aesthetic.⁹³

Figures are suggestions of formations and movements. Descartes combines speculation on the makeup of invisible particles with a sensual approach to their composition. The key to figurability in Descartes’s writings can, indeed, be seen in his treatise on music. The ground of figures is based on a kind of rhythmic seriality of duplicity and change. Rhythm shapes the particles so as to suggest endless combinations. Just like the atmosphere, through wind, snow, and so on, gives witness to the spinning of invisible structures, so does musical experience imply movements in the atmosphere that the eye cannot perceive.

Descartes the natural philosopher or “physicien” examines music in the same way as the atmosphere.⁹⁴ This means working by a form of reasoning that only superficially resembles deduction; it builds more on sense experience and figuration, and the attempt to understand what connects atmospheric movements to passions. The notation of tones expresses the same kind of movement as tones that we hear, Descartes argues.⁹⁵ The invisible vibrations of the atmosphere in music are subject to algebraic calculation as well as sensual shaping, just like the invisible realm of particles in physics. Figures seize the variables of regularity as well as of distinction. This is also the key to aesthetic experience. The pleasure that we may experience in music is produced through the differentiation of tones. I cannot tell you which musical octave I find the most beautiful, Mersenne responds to a question posed by Descartes, because the senses cannot distinguish their repercussions in the atmosphere.⁹⁶

The notion that the figures can be seen as preconceptual gatherings in a universe of infinite varieties, of proportions and space, can be seen in relation to contemporary philosophy’s theorization of rhythm as a descriptor. Rhythm has passed, in the phenomenological tradition, from being described in the constitution of consciousness, to acquire the status as a descriptor in posthuman philosophy of nature. In the work of Husserl, rhythm is not only repetition or sequence but also the constitution of an inner consciousness that crosses the line between self and world, affect and perception.⁹⁷ This is made clear also in the world of extension identified by Descartes: colors appear in a form of “numeric identity” in the thing-bodies that appear visually.⁹⁸ What we perceive through our senses is offered to us through forms of regularity and repetition; this is, in Husserl’s aesthetic reflections, often aligned with the understanding of aesthetic forms themselves, such as images and painting and music.⁹⁹ However, after Husserl, in the work of Maurice Merleau-Ponty, rhythm is not seen as constitutive of consciousness but rather as an aspect of the way in which the world of extension is inhabited by other beings. Rhythm is life beyond the human; it can be identified in the “crawling” offered to us through a line of light or in a painting where rhythm can be perceived as an atmosphere, a sense of space, a new dimension of perception.¹⁰⁰ In this way, rhythm is an aspect of aesthetic perception as such: although nonhuman as descriptor, it implies that we see the world as inhabited and that our perception is intertwined with that of other living beings.¹⁰¹ Merleau-Ponty also suggests that forms we tend to perceive of as wholly abstract may still be enveloped in a sense of rhythm. We may experience even a line of light as the rhythm of living movement. Through its “crawling,” it becomes a “virtual substance.”¹⁰²

Figure 4.6. Clouds, Les Méteores. In Discours de la methode, Leyden: 1637, Royal Library Stockholm.

Figure 4.7. Wind, Les Météores. In Discours de la methode, Leyden: 1637, Royal Library Stockholm.

In music or painting, rhythm deploys depth of expression, as Jessica Wiskus has shown. Rhythm emanates from a line that is “freed”; it becomes a membrane through which “a certain depth or volume radiates.”¹⁰³ The different lines of blue that are used in Cézanne’s Four Bathers, for instance, indicate living tissue, intertwining the world of living beings and space.¹⁰⁴ This implies that rhythm, irreducible to anthropomorphic shapes, gives depth and space to perception without being inherent to consciousness as such; there are, so to speak, shapes of rhythm “out there.”

Rhythm is also a category used in theories of the posthuman, a term employed to point to forms of meaningful creation that do not translate into anthropomorphic ideas or concepts. Famously, the art exhibition Documenta XIII in Kassel in 2012, with its focus on ecological systems, brought this into attention. It engaged a shift from representation to the action on and between bodies in modes that can be described in terms such as affects, flows, and rhythm. Exchanging signs of representation for “abstract descriptors,” such as emotions, instincts, rhythms, and flows, a landscape or weather can be as much of an aes-thetic experience as music or painting.¹⁰⁵ In this conception, rhythm is not so much a depiction of life, as it tends to be in Merleau-Ponty’s phenomenology, where it gives witness to the interconnection between bodies and human life. It is rather something that happens in the intertwinement between the seriality of the designator and the qualities of extended bodies inherent to the experience. One can compare with the rhythmic drawings of Cy Twombly, where the rhythmicality is produced by the techniques, materialities, and modes of work. What transpires is a rhythmic movement that stands as itself. It is not a thing, and it is not a matter. Neither is it a body. It comes across as a figuration in and through the lines themselves. Although the figural rhythm seen in Twombly can perhaps be conceived as time, the extension in space matters even more perhaps; the lines are curved as a result of a certain timing. What makes a rhythm protrude is not the repetition of the same but rather the differentiation, the way in which a sequence differs against another sequence. But most importantly: the rhythmicality lies in the open-endedness of the figure. The lines of Twombly’s drawings are uncontained. They move on, outside of the image. This move, beyond, implies some kind of infinity, a metaphysics perhaps.

Figure 4.8. Cy Twombly, Untitled, 1969. Oil paint, wax crayon.

© Cy Twombly Foundation.

For Descartes as well, lines are not just abstract shapes; they are also flowing motions.¹⁰⁶ In this way, the rhythmicality of the images implies an infinity, a cosmic dimension. This dimension is irreducible to mathematics, or reason. Lines belong not only to the world of geometry. They designate formations of emotions, instincts, rhythms, transformations, and flows that affect bodies. Descartes’s fondness for rhythmically composed figures may be seen in this light. Lines capture movement in rhythmic formations and become thought. Lines cross the limits between imagination, embodied experience, and the physical movement that lies beyond. They carry us over to what we cannot perceive: spinning beyond the composition of the figures—nothing can be imagined that cannot be solved by a line, as he writes to Beeckman.

The relation between the figures of Descartes’s Meteorology and Compendium on Music can be seen in this light. His analysis of tonal value is figured not only through musical notation but with a variety of figures that explain the differences between harmonies, rhythms, and other kind of musical expressions. In this way, the figures in Meteorology and Compendium on Music serve similar purposes: they may “fail” to ascertain knowledge, but they seize a dimension between the abstract and the sensual. Compendium on Music suggests that rhythm is more important than harmony: through rhythm, “sound strikes all bodies on all sides.” It is a physical motion, like “bells and thunder,” that will induce passions like “languor, sadness, fear, pride,” and so on.¹⁰⁷ Through rhythm, the senses enwrap the whole body. Even animals can learn to dance. Rhythm is also what produces the passions that music shares with poetry.¹⁰⁸ Descartes then notes that rhythm may also appear when it is not produced as music: as ordinary sounds that take on a certain regularity, such as creaking windmills. Rhythm is produced, then, through the very appearance of patterns. It appears also as threads. In rule ten in Rules, Descartes perceives aesthetic qualities as the patterns of ordering in the every day. Such patterns are particularly adapted to human cognitive capacities. In fact, ordering is often an aspect of the products of everyday life, for instance, weaving or carpetmaking. Regularity and differentiation cooperate in “the more feminine arts of embroidery, in which threads are interwoven in an infinity of varied patterns.”¹⁰⁹ This is what differentiates rhythmic form from mere algebraic composition: like in the discourse on salt, rhythm catches not only the patterns of the particles but also the spinning of differentiation.

Rhythm, in the figures of Descartes, is produced by lines. They figure movements and transformations of the universe that lie beyond our reach. Descartes’s drawings are strikingly articulate in rhythm, line, and allusions. At once economical and expressive, they contain a language. What makes rhythm protrude, and what makes the figure cohere with the treatises, is not simply the repetition of lines, of snowflakes, eels of water or tables of salt, and so on, it is the spinning of differences and the modes of penetration by which bodies intertwine with other bodies. Rhythms are produced by lines in a repetitive mode of shapes, using stress, timing, shades, and nuances to create the open-endedness of figures, between sensual expression and suggestion of abstraction.

Indeed, the images challenge the dualism between res cogitans, the subject, and res extensa, material bodies.¹¹⁰ We feel the weather and the matters that create it as hot and cold, hard or soft, slippery or metallic; these properties guide the imagery of invisible particles. In Principles of Philosophy, Descartes refers to this as some kind of practice: we are prone to use our experience of large bodies to understand what lies beyond the senses. We need to apply mathematical and mechanical rules to understand the shapes, sizes, and motions of the small bodies that elude the eye.¹¹¹ But we still need to use the senses to grasp the presence of invisible, penetrable particles. This is what figures help us do: we grasp what we cannot see through what we can see. For this, the figures of the observations need not be exact. The visualizations may be exaggerated.

Many have questioned the relation between Discourse on Method and the treatises Optics, Meteorology, and Geometry that followed. To Descartes, it appears to have been perfectly coherent, because Discourse was applied as offering the rules for what was to provide a knowledge of certainty.¹¹² It was rather the case that relation between the mind and its grasp of the world of extension demanded sensual deliberation through drawings and sketches—that were able to provide images of the invisible. In this way, the dualism in Descartes is both erected and shattered at the same time: the senses cannot perceive the small particles, but they are nevertheless posited from a position where a combination of sensual experience and mathematical formula are necessary to grasp them. As Merleau-Ponty described in his notes on Nature, Descartes’s philosophy of nature is in search of an “ontological midpoint” in order to resolve the problematic duality between object and mind, order of causality and order of meaning.¹¹³ Such a midpoint produces a viewpoint that straddles two different aspects at the same time; as Renaud Barbaras puts it: the “abstract object” offered by Descartes is, to Merleau-Ponty, the result of a strife to find an original meaning that looks at both its singularity and its place in a causal chain.¹¹⁴ Seen from this perspective, the images are an integral part of the struggles not to reduce nature’s own expression. They are descriptors transgressing the dualism between the mind’s abstraction and corporeal, sensual experience.

The aesthetic dimensions of scientific hypotheses in Meteorology are indeed putting several dualisms in motion: between passion and knowledge, image and text, rhythm and geometry. Weather does not need thought, but thought needs aesthetic means to seize the depictions of a multitude. This is not the only example where Descartes both raises and challenges dualisms within his own writings. The charges against Descartes as an abstract humanist appear to lack a distinct target; Descartes’s version of seventeenth-century humanism was never a rigid model of reason’s sovereignty.¹¹⁵ In this context, the aesthetic elaboration of Meteorology, embodied in its figures, can be inserted. The weather gives witness to the limits of reason: the varieties of its composites are infinite.¹¹⁶ This insight is integral to Meteorology overall.

Cartesian engravings are not intended to illustrate what the text says about the particles of nature, as a secondary source of imitation of what lies “out there.” They are rather the result of experimental imagination. Rhythm is not repetition or sequencing; it is differentiation in and through figures. One can see this not only in the natural philosophy but also in the treatise on music.¹¹⁷ Only the intellect “is capable of perceiving the truth.” But we must sometimes use imagination and sense perception to acquire knowledge.¹¹⁸ Only the senses can seize the imperceptible forms of differentiation that make up the Cartesian. This inquiry into the relation between the intellect’s capacity for abstraction, and the figures as conglomerates of sensation and experience, permeates Meteorology. The images in Meteorology are not primarily a pedagogical feat; they are not mimetic interpretations of phenomena. They are an aspect of the knowledge produced.