Baroque Science

In Baroque Science, Ofer Gal and Raz Chen-Morris present a radically new perspective on the scientific revolution of the seventeenth century. Instead of celebrating the triumph of reason and rationality, they study the paradoxes and anxieties that stemmed from the New Science and the intellectual compromises that shaped it and enabled its spectacular success. Gal and Chen-Morris show how the protagonists of the new mathematical natural philosophy grasped at the very far and very small by entrusting observation to the mediation of artificial instruments, and how they justified this mediation by naturalizing and denigrating the human senses. They show how the physical-mathematical ordering of heavens and earth demanded obscure and spurious mathematical procedures, replacing the divine harmonies of the late Renaissance with an assemblage of isolated, contingent laws and approximated constants. Finally, they show how the new savants, forced to contend that reason is hopelessly estranged from its surrounding world and that nature is irreducibly complex, turned to the passions to provide an alternative, naturalized foundation for their epistemology and ethics. Enforcing order in the face of threatening chaos, blurring the boundaries of the natural and the artificial, and mobilizing the passions in the service of objective knowledge, the New Science, Gal and Chen-Morris reveal, is a Baroque phenomenon: deeply entrenched in and crucially formative of the culture of its time. Excerpt CHAPTER 1

Science's Disappearing Observer

Baroque Optics and the Enlightenment of Vision

INTRODUCTION

IN THE SEVENTEENTH CENTURY the human observer gradually disappears from optical treatises.

Traditional optics studied human vision. The standard of all medieval optical works, Alhacen's grand Kitab al-Manazir (c. 1030), declares vision as its subject matter in its very title, properly translated to Latin as Aspectibus. Vision is also the subject matter of John Pecham's Perspectiva Communis (c. 1280), and it still comprises the fifth chapter of Kepler's 1604 Optics. In the 1630s, however, René Descartes exiled vision from the Treatise on Light and Dioptrics to the Treatise on Man. Robert Hooke mentions the eye in the 1665 Micrographia only when discussing instruments, and vision is completely missing from Christian Huygens' 1678 On Light. When Isaac Newton reintroduces the eye in his Optical Lectures and New Theory of Light and Color, it is no longer as the telos of the optical process, but as a seat of natural phenomena. Indeed, the spectacularity of Newton's New Theory derives from the extravagant difference between the physical objects of optics (monochromatic rays) and the perceived object of vision (white light); a thorough reversal of simple and complex.

The divorce of optics from theory of vision is a paradoxical process. It does not reflect a disengagement of the human eye from its objects. Quite the contrary: the observer disappears from optics because of the evolving understanding of the eye as a natural, material optical instrument. It is the naturalization of the eye that begets the estrangement of the human observer from nature. The naturalized eye no longer furnishes the observer with genuine re-presentations of visible objects. It is merely a screen, on which rests a blurry array of light stains, the effect of a purely causal process, devoid of any epistemological signification. It thus falls upon the intellect to decipher a purely natural phenomenon—a flat image—as the vague, reversed reflection of an object of no inherent relation to it.

The estrangement of the observer, its origins in the optical paradox, and its momentous ramifications are the subject matter of this chapter.

KEPLER

Artificiosa Observationes

The human observer starts slipping out of optics when Kepler turns his optical opus magnum, the Ad Vitellionem paralipomena to artificial observations:

On 1602 21/31 December at 6h in the morning, through a device described in Ch. 2 [camera obscura] and an instrument made for this purpose, a description of which is furnished below, the moon made an image of itself brightly upon the paper lying below, inverted in situation, just as it was in the heavens, gibbous ... You should not think that what I would consider to be in the moon's ray was in the paper, for both the gibbous face and the spot in its middle were carried over to all parts of the paper whatever that was placed beneath it; rather, indeed, it was from moving the paper that the spot was first discovered.

The observation, Kepler stresses, is not his. It is nobody's. The image of the moon is not the culmination of a cognitive process. It does not require an observer; a piece of paper is enough. In fact, even the paper is not necessary: it can be moved around without affecting the production of the image. This production is the main concern of Ad Vitellionem: being "The Optical Part of Astronomy," it is about the making of observations rather than their content. Earlier on in the book Kepler establishes the legitimacy and efficiency of his main instrument of artificiosa observationes (the term he uses in one of the subtitles of Ad Vitellionem), the camera obscura, by demonstrating that the image obtained through it is indeed that of the observed object. He goes on to elucidate its underlying principle—namely the formation of an image on a screen behind a small aperture—by way of physical simulation:

I set a book in a high place, which was to stand for a luminous body. Between this and the pavement a tablet with a polygonal hole was set up. Next, a thread was sent down from one corner of the book through the hole to the pavement, falling upon the pavement in such a way as to graze the edges of the hole, the image of which I traced with chalk. In this way a figure was created upon the pavement similar to the hole. The same thing occurred when an additional thread was added from the second, third and fourth corner of the book, as well as from the infinite points of the edges. In this way, a narrow row of infinite figures of the whole outlined the large quadrangular figure of the book on the pavement.

The threads from the book's corners pass through the edges of the polygonal hole, projecting images in the shape of the hole—a hole-shaped image for each corner of the book. The four images of the book's corners will be arranged on the floor in reversed order, and when this process is repeated from (ideally) every point of the book, a multitude of hole-shaped images will be projected on the floor, arranged in the (reversed) pattern of the book.

This is a neat solution to an age-old mystery, but the solution is not where the main novelty of Kepler's analysis rests. Neither the phenomenon of pinhole images, on which the camera obscura is based, nor its account in terms of intersecting rays is new to the optical tradition. Already in the Problemata pseudo-Aristotle asked, "Why does the sun penetrating through quadrilaterals form not rectilinear shapes but circles, as for instance when it passes through wicker-work?" In the late thirteenth century John Pecham formulated the phenomenon thus: "Incident rays passing through angular apertures of moderate size appear rounded [when they fall] on facing bodies, and always become greater [in breadth] with greater distance [from the aperture]." The notion that the phenomenon arises somehow from the intersection of the rays at the aperture was also available to the optical tradition at least since Levi ben Gershon (Gersonides) in the beginning of the fourteenth century. Kepler cites both "Rabbi Levi" and Pecham (under the wrong name Pisanus), and for good reasons. Levi (as well as Francesco Maurolyco and others) uses the assumption that the roundness of the image is a reflection of the roundness of the sun in the way Kepler intends to use his account of the phenomenon: as a justification for the use of the pinhole for solar observations. But this is exactly where Kepler's indebtedness also ends.

For the perspectivists, the pinhole image is not just a reliable projection of its source. It is unique re-presentation of the sun. The circular image is not caused by the sun and by light; it is the true form of the sun or the perfect dissemination proper of light, as Pecham explains:

The spherical shape is associated with light and is in harmony with all the bodies of the world as being to the highest degree conservative of nature, all parts of which join together most perfectly within itself. This is why a raindrop assumes roundness. Therefore, light is naturally moved toward this shape and gradually assumes it when propagated some distance.

Understood this way, the circularity of the image does not simply testify to a property of its source; it is a sign of the image's indubitable authenticity. This essential relation between source and image completely disappears from Kepler's account, together with the exactness of representation it ensures. There is nothing unique to the circularity of the pinhole image: a rectangular body will produce a rectangular image, as the experiment with the book shows. Neither does the pinhole image represent light: it is light, as we shall see below, that is simulated by the threads pulled through the hole, but the image projected on the pavement can be of any object, not necessarily luminous—a book. The trustworthiness of the projection, for Kepler, does not rest on its perfect loyalty to the object projected but on understanding the physical process of projection. Indeed, Kepler discovers, one cannot hope for such loyalty: The book pattern on the floor is created by a "narrow row" of partially overlapping "figures," so not only is the image reversed, its boundaries are fuzzy. Moreover, these stains are a reflection of the aperture. For Maurolyco, who may appear to suggest a similar account, the image cast through the aperture is composed of many images of the luminous body. These are merged together as the distance from the screen to the aperture grows, and the images of the source grow accordingly. Kepler is well aware of this option. Besides the image that "consists of shapes that are potentially infinite, similar to the window, mutually overlapping," he also posits "infinite, individual inverted images of the luminous surface," passing through "the individual (and thus infinite) points of any window." Yet for him this only means further complexity: "The shape of a ray on the wall is a mixture of the inverted shape of the luminous surface and the upright shape of the window." Kepler's "figures" bear no inherent resemblance to the light source. The complete, smooth, upright perception of the book on the pavement is a construct.

The Challenge of Astronomy

However, Kepler's interest is in the legitimation of the instrument, not its demise. The challenge he takes on in the Ad Vitellionem is "to preserve astronomy's dignity and to subdue the hostile fortress of doubt," and in this he addresses a very genuine worry. Towards the end of the sixteenth century the legitimacy of astronomy's claim to knowledge was assaulted by the likes of Zabarella, Carbone, Ursus, and Frischlin:

God the Creator placed [the heavenly] bodies so far away from our senses that we are unable to produce principles of demonstration for them (as we can in the sciences of other things) or to discover what is natural and familiar, by means of which we may afterwards set out the causes of particular appearances.

The notion that the heavens are too far to be observed goes back to Aristotle, for whom this distance means that "the evidence [concerning celestial bodies] is furnished but scantily by sensation." It troubled even the most committed astronomical reformers; Kepler's mentor Michael Maestlin, a staunch Copernican, still felt compelled to point out that "no one is able to ascend to the aethereal region, where he would see everything in person." Any claims to "principles" or "causes" in the heavenly realm lay beyond the boundaries of astronomical knowledge. Even Tycho Brahe, whose determination of the heavenly place of the Stella Nova of 1573 and the comet of 1577 was of such obvious and far-reaching cosmological significance, had to concede that. In his debate with Rothman over the question of the heavenly matter, Brahe acknowledged that in the final account, as a physical problem, the matter of the heavens was inscrutable (imperscrutabilis).

This physical realm, however, was exactly where Kepler intended to take astronomy. "Physicists, prick up your ears!" he would declare in the introduction to his Astronomia Nova (not published until 1609, but already being composed), "for here is raised a deliberation involving an inroad to be made into your province." The eye is particularly deficient in providing the evidence required for this grand new venture:

the eyes are attached to the head, so, through the head, they are attached to the body; through the body, to the ship or the house, or to the entire region and its perceptible horizon.

Hopelessly embodied and situated, "the sense of vision is in error about the movable." It is thus unable to adjudicate between "Copernicus, whom I follow," Ptolemy, and Tycho, let alone support the ambitious claims of his physica coelestis. Since (reiterating Maestlin) we do not have "someone ... to carry us across to the moon or to another of the wandering stars" (which would help little, Kepler points out), Kepler requires a new agent to bridge the epistemological rift and carry images from the far away.

Light and the Transformation of Optics

Kepler's agent is light:

I firmly established by irrefutable experiments, that ... from the Sun, and from the colors illuminated by the Sun, species exactly alike are flowing, diminished by the flow itself, until for whatever reason, they fall on an opaque medium, where they paint their source: and vision is produced, when the opaque screen of the eye is painted this way ... and it is confused when the pictures of the different colors are confused, and distinct when they are not confused.

For there are certain passions of light, or of rays descending from the illuminating bodies, qua light, not qua inhering in the transparent air, the modes of which are emission and extension, and their contrary, reflection and refraction or condensation. Therefore, nothing prohibits a certain action to be of the same light ... illuminating and altering the screens [of the eye] through which colors, that is to say light, are not only poured upon but are also imprinted and the contraries are destroyed.

It is light that generates images, bouncing off "an opaque medium" and falling on an "opaque screen." If it happens to be "the opaque screen of the eye"—the retina—"vision is produced," but there is nothing unique to the eye: any screen will do.

With light as the sole agent of all optical phenomena, there is no fundamental epistemological difficulty with observing the distant celestial phenomena: the mathematical nature of light and the conviction that the rays do not decay but only disperse (propositions 6 and 7 of Ad Vitellionem) turns distance into nothing but an element in the geometrical analysis of observation. And with light, there is no epistemological difficulty with artificiosa observationes. The image on the pavement is reversed and fuzzy, but so is the one on the retina. The instrument is trustworthy not because it does not interfere with the visual flow, but because it is no worse than the eye.

Kepler turned optics into a mathematical-physical study of the production of images by light. Light optics dissolved the dichotomy between instrument and eye, mediated and direct observation, and set the stage for a new type of observation, to which we will return in chapter 3. In general, the assumption that light is mathematical in essentia was a powerful intellectual instrument for Kepler in fields other than optics, and in chapters 4 and 6 we will discuss the role it played in the mathematization of natural philosophy. The ramifications of turning optics into "physica" tend to be obscured by his obvious indebtedness to the perspectivist tradition acknowledged by titling his optical treatise after Witelo—but Kepler's transformation of optics was fundamental.

The subject matter of traditional optics was human vision. Its basic assumption, as we will discuss in the next chapter, was that vision is a direct acquaintance of the visual faculty with visible objects, and optics is the study of the agents whose function is to communicate these objects to the eye. This communication—the optical process—has always been self-evidently teleological. It was aimed at providing adequate images of visible objects for the intellect: "a species produced by a visible object has the essential property of manifesting the object of which it is the likeness" says Pecham. Kepler was well aware of this: "Aristotle defines light," he writes, "not ... in its nature, but to the extent that it is characteristic of the process of vision." The assumption of visual teleology survived throughout the Renaissance. Summarizing scholastic optics for his audience of painters and art patrons, it is the one aspect the great theoretician of artificial perspective, Leon Battista Alberti (1406–72), chooses to stress:

philosophers ... say that surfaces are measured by certain rays, ministers of vision as it is (quasi visendi ministris), which they therefore call visual rays, since by their agency the images of things are impressed upon the senses.

This metaphysical assumption had clear practical ramifications: "Alberti's picture," Svetlana Alpers points out, "begins not with the world seen, but with a viewer who is actively looking out at objects." The physical nature of the "ministers of vision" was debated since antiquity: simulacra or forms, visual rays or species, but their teleology and authenticity were never in doubt. Grosseteste, for instance, founds them on the premise that it is an essential property of the visible object itself, its agency or "virtue," which "multiplies" itself until it made itself present to the eye:

A natural agent continuously multiplies its power from itself to the recipient, whether it acts on sense or on matter. This power is sometimes called species, sometimes a likeness, and it is the same thing whatever it may be called.

Following Grosseteste's teaching, Roger Bacon underscores the essential relation that assures the trustworthiness of the multiplied agents to the visible object: "species is similar in essence and definition to the agent and the things generating it." The authenticity of species was a fundamental assumption not only of optics but of medieval Aristotelianism as a whole; optics legitimated natural philosophy by accounting for the fundamental knowability of His Creation. Visual rays guaranteed the veracity of vision, and the geometrical analysis of their propagation was always subsidiary to the assumption of their intentionality and their consequent indubitability. So was the analysis of the eye, as Pecham stresses: "vision takes place by the arrangement of the species on [the surface of] the glacial humour exactly as [the parts] of the object [are arranged] outside" (italics added). This is so, precisely because "unless this were so, the eye would not see the object distinctly." Optics, he assumes, is a theory of visual perception, and any such theory that failed to account for the adequacy of the seen image is ipso facto false.

(Continues...)
(Continues...) Excerpted from Baroque Science by OFER GAL, RAZ CHEN-MORRIS. Copyright © 2013 by The University of Chicago. Excerpted by permission of The University of Chicago Press.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site. In __Baroque Science__, Ofer Gal and Raz Chen-Morris present a radically new perspective on the scientific revolution of the seventeenth century. Instead of celebrating the triumph of reason and rationality, they study the paradoxes and anxieties that stemmed from the New Science and the intellectual compromises that shaped it and enabled its spectacular success. Gal and Chen-Morris show how the protagonists of the new mathematical natural philosophy grasped at the very far and very small by entrusting observation to the mediation of artificial instruments, and how they justified this mediation by naturalizing and denigrating the human senses. They show how the physical-mathematical ordering of heavens and earth demanded obscure and spurious mathematical procedures, replacing the divine harmonies of the late Renaissance with an assemblage of isolated, contingent laws and approximated constants. Finally, they show how the new savants, forced to contend that reason is hopelessly estranged from its surrounding world and that nature is irreducibly complex, turned to the passions to provide an alternative, naturalized foundation for their epistemology and ethics. Enforcing order in the face of threatening chaos, blurring the boundaries of the natural and the artificial, and mobilizing the passions in the service of objective knowledge, the New Science, Gal and Chen-Morris reveal, is a Baroque phenomenon: deeply entrenched in and crucially formative of the culture of its time.

In Baroque Science, Ofer Gal and Raz D. Chen-Morris present a radically new perspective on the study of early modern science. Instead of the triumph of reason and rationality and the celebration of the discoveries and breakthroughs of the period, they examine science in the context of the baroque, analyzing the tensions, paradoxes, and compromises that shaped the New Science of the seventeenth century and enabled its spectacular success. Gal and Chen-Morris show how scientists during the seventeenth century turned away from the trust in the acquisition of knowledge through the senses towards a growing reliance on the mediation of artificial instruments, such as lenses and mirrors for observation and mechanical and pneumatic devices for experimentation. Likewise, the mathematical techniques and procedures that allowed the success of mathematical natural philosophy turned increasingly obscure and artificial, and in place of divine harmonies they revealed an assemblage of isolated, contingent laws and constants. In its attempts to enforce order in the face of threatening chaos, blur the boundaries of the natural and the artificial, and mobilize passions in the service of objective knowledge, Gal and Chen-Morris reveal, the New Science is a baroque phenomenon.

In Baroque Science, Ofer Gal and Raz D. Chen-Morris present a radically new perspective on the study of early modern science. Instead of the triumph of reason and rationality and the celebration of the discoveries and breakthroughs of the period, they examine science in the context of the baroque, analyzing the tensions, paradoxes, and compromises that shaped the New Science of the seventeenth century and enabled its spectacular success. Gal and Chen-Morris show how scientists during the seventeenth century turned away from the trust in the acquisition of knowledge through the senses towards a growing reliance on the mediation of artificial instruments, such as lenses and mirrors for observation and mechanical and pneumatic devices for experimentation. Likewise, the mathematical techniques and procedures that allowed the success of mathematical natural philosophy turned increasingly obscure and artificial, and in place of divine harmonies they revealed an assemblage of isolated, contingent laws and constants -- Provided by Publisher Contents 8 List of Figures 12 Acknowledgments 14 Introduction 8 Part I. Observation 28 1. Science’s Disappearing Observer: Baroque Optics and the Enlightenment of Vision 30 2. Per aenigmate: Mirrors and Lenses as Cognitive Tools in Medieval and Renaissance Europe 68 3. The Specter of the Telescope: Radical Instrumentalism from Galileo to Hooke 94 Part II. Mathematization 130 4. Nature’s Drawing: Problems and Resolutions in the Mathematization of Motion 132 5. From Divine Order to Human Approximation: Mathematics in Baroque Science 176 6. The Emergence of Baroque Mathematical Natural Philosophy: An Archeology of the Inverse Square Law 200 Part III. Passions 246 7. Passions, Imagination, and the Persona of the New Savant 248 Abbreviations 298 Notes 300 Bibliography 328 Index 346