Vermeer was also looking inside, in a way that was perhaps more subtle but no less striking. This is especially apparent in his eleven pictures depicting solitary women absorbed in their tasks—paintings that are among those most beloved today. In works such as The Milkmaid, Woman in Blue Reading a Letter, Woman with a Pearl Necklace, Woman with a Balance, and The Lacemaker, we feel that we have come upon these women, who are unaware of our presence; we are eavesdropping on their activity, “quietly peep[ing] in at the window,” just as Hooke had hoped to eavesdrop on his specimens, without any violence or interference. We sense not only that we are watching these women engaged in their occupations, but that we are witnessing a part of the inner life of these women, a contemplative side. These women of Vermeer’s are full of thoughts, though we do not know what they are. This is especially the case in the six letter pictures. Reading a letter, or writing one, even receiving one, fills one with thoughts and emotions. The viewer of paintings such as Woman in Blue Reading a Letter or Mistress and Maid is eavesdropping on an inner state of mind and heart.
Just as Van Leeuwenhoek so masterfully employed optics to see with his microscope and peep in on his specimens, Vermeer exploited the optical qualities of his pictures to evoke the sensation of voyeurism. For instance, in Woman in Blue Reading a Letter, Vermeer was scrupulous in painting the shadows cast by the map on the wall and by the two chairs. This makes the scene look so real, with such a sense of three-dimensional space, that we feel we have stumbled upon the woman reading. Her absorption in the letter is complete; she does not know we are there, intruding on her privacy. But the woman herself casts no shadow. She exists in the space of the picture, and yet outside of time; she is unaffected by the passage of time, by the movement of the sun across the sky. This keeps her apart from us, beings who do exist in time. So we see her, but we are not a part of the scene, or of her life. We are kept at a distance, quietly peeping in.
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Both Van Leeuwenhoek and Vermeer were using optical devices to see what had previously been unseen. Van Leeuwenhoek saw microscopic creatures for the first time. He also saw structures of animals and plants that had never been seen: blood corpuscles, mold spores, and sperm. Hooke had proclaimed that the microscope would enable investigators to discover “new Worlds and Terra-Incognita’s [sic],” just as Columbus had “discovered” a new world. After Van Leeuwenhoek it was no longer taken for granted that the world visible to the naked eye was all there was; lenses were now presumed to help us see deeper and farther. There was an acknowledged unseen part of nature no less thrilling than the seen.
Vermeer, too, was seeing what had not really been seen or, better, what had not been noticed—the way colors change under different conditions of light, even though our eyes seem to see them as unchanged, the way that a hand can look like a lump of flesh, depending on the light and our position relative to it, and the way shadows can be brown, green, yellow, or blue. The camera obscura helped Vermeer pay attention to optical qualities not usually noticed, to disrupt the painter’s habits of seeing and depicting his figures. Most painters—and the viewers of their pictures—are willing to accept shorthand methods of recognizing and representing objects, such as the perfectly formed hand even in dark shadow, or the dress in a single color under varying conditions of light. But through the lens of the camera obscura Vermeer would have seen, and noticed, what is usually missed—and this may be why Vermeer was not afraid to deform familiar objects, even though most painters avoided this effect.
And, like some of his fellow Dutch painters, Vermeer saw—with all of his attention—his women subjects, really saw them as individual women. In his pictures of women reading letters, being courted, playing music, or caught during their daily domestic chores, Vermeer captured their particular expressions, their movements and gestures. These women have a specificity that is lacking in the conventions of classical and baroque depictions. They are not idealized women offered to the male gaze, as we find in works by many earlier artists, but individual women seen as individuals by the painter.
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The work of Van Leeuwenhoek and Vermeer exemplified a particular notion of seeing, one that emerged only in this period with the birth of optical instruments and the new theories of vision. This notion accepted that seeing was a complex matter—involving much more than just rays coming either to or from the viewer’s eye. Beliefs, expectations, desires, and prior knowledge all play a role in how we see the world. As Galileo had said, one must use “the eyes of the mind as well as the eyes in the head” in order truly to see with the telescope. Andreas Colvius had similarly remarked, upon receiving one of the early microscopes of Christiaan Huygens, “who among the ancient philosophers had indeed penetrated into the secrets of nature with the eyes of both the body and the mind as did the savants of the present age?”
But the mind’s role in seeing was a double-edged sword. On the one hand, being able to interpret the shapes and structures seen with the telescope and the microscope was a learned skill, something that took time. It was, as Van Leeuwenhoek realized, necessary to learn to see. Knowledge and beliefs could help prepare the eye, as when Galileo’s knowledge of perspective theory—and his acceptance of Copernicus’s sun-centered universe—allowed him to see the blotches on the moon as craters. Like other microscopists, and like users of the telescope, Leeuwenhoek needed to learn how to use the knowledge he had to help him see with his device.
On the other hand, the mind’s involvement in seeing could unduly influence what was seen, or not seen. Galileo’s opponents, strong supporters of the Aristotelian cosmology, simply could not see the lunar craters. Van Leeuwenhoek realized that what one thinks he sees is related to what he wants to believe. Believing is seeing, sometimes. Van Leeuwenhoek needed to train himself to see what was there, not what he expected to find. When he viewed the corpuscles in blood, he saw them as globular, even though they are flatter, with a central concavity. It wasn’t only Van Leeuwenhoek—everyone at the time who saw those structures in the blood reported seeing a globular form. Swammerdam, the instrument maker Musschenbroek, and the observers at the Royal Society all saw the corpuscles as globules, because that is what they expected to see. Indeed, at first Van Leeuwenhoek saw globules everywhere: in blood, in milk, in bile, salt, chalky earth, yeast, wine, hair, semen, and other specimens. To be sure, the observations were difficult. Even John Locke, observing the spermatozoa of a dog with Van Leeuwenhoek in 1678, had a hard time seeing the tails: “they seemed to me like very small beads,” Locke admitted. Over time, Van Leeuwenhoek realized that he had been inclined to see globules as the building blocks of all matter because of his adherence to corpuscularism. He had to fight against that impulse. He would soon see the tails of the spermatozoa in semen—even pointing them out to Locke—and reject globules in muscle fiber and in tooth enamel.
Van Leeuwenhoek had learned that one’s presuppositions could confuse observations made through lenses. That was why he counseled that the microscope user make many observations under different conditions in order to fight against this natural tendency. It was not enough to use the “simple Eye,” he affirmed again and again, what was needed was “attentive observation”—especially with a microscope. Van Leeuwenhoek emphasized frequently how many times he made himself repeat observations before drawing conclusions and feeling secure about what he saw. It was such repeated and attentive observations that led him to abandon his earlier observations of globules in all things. It also led him to reject, though reluctantly, the idea that a sperm contained the entire adult animal in miniature—or, at least, that he could see it there.
Artists, too, were using mirrors and lenses to engage in attentive observation in order to learn to see. By looking at a composition on the flat surface of a mirror, or through the slightly curved surface of a lens, painters saw more clearly what had not been noticed before. As Leonardo da Vinci had said, the painter could use a mirror to help him “develop his senses.” Vermeer used the camera obscura to d
evelop his sense of sight, to notice natural optical effects lesser painters had missed: the color of shadows, the way an object changes color depending on the lighting, how light glances off the nails of a chair. Vermeer realized, too, that visual perception supplies omitted detail when the viewer has certain expectations. As several writers have observed, and as Steadman nicely puts it, in Girl with a Pearl Earring, “there is no line at all following the profile of the girl’s nose on the left-hand side. The bridge of the nose is given precisely the same color and tone as the cheek beyond. The lines of the right side of the nose and nostril are nearly lost in shadow. And yet we imagine and read an outline, and so a form, because of our prior knowledge and our reading of the shape and the shadow. The upturned face of the woman receiving a missive in Mistress and Maid is merely a blur of color, and yet we can read concern, even worry, within its contours.
Similarly, in Woman in Blue Reading a Letter, Vermeer used ultramarine as a thin glaze over the ocher ground for the jacket. However, in the deep shadows at the back of the jacket, he used mainly black, which he layered over the ground. Vermeer mixed the black with the blue glaze in some spots, in others used the black as a base for a touch of blue pigment. Indeed, very little blue can be found in either the highlighted part of the jacket or the part in shadow; he established the jacket’s overall blue color with a minimum of the precious blue ultramarine paint. He relied on the visual habits of the viewer to combine the various tonalities into a coherent, predominantly blue, whole. It was because of his experimental study of visual perception that Vermeer could paint works depicting our visual experience so luminously.
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The transformation of art and science that took place in the Dutch Republic in the seventeenth century—in great part due to two of its citizens, Vermeer and Van Leeuwenhoek—changed forever how people saw the world around them. It was not only the novelty of microscopic observations, experienced by a public who used “toy microscopes” and flea glasses to see the cheese mites crawling on the rinds of Goudas. Nor was it just the new way that light, shadow, and perspective were depicted—though not often with the bravura of Vermeer’s works—in the millions of pictures purchased by eager buyers during this period. A broader shift had occurred, one that cleaves the history of perception into two: before this moment and after it. For the first time, people knew with certainty that there was more to the natural world than meets the naked eye. They learned that they could see this invisible world with optical devices. And, by using these instruments, they came to understand that we must learn to see—both with the new devices and with our own visual systems. These three ideas are fundamental to how we understand our world and the way we gain knowledge of it today.
Van Leeuwenhoek, and then other microscopists, proved the existence of a previously invisible part of nature. Once this breathtaking discovery had been assimilated, the race was on to fashion new, more powerful instruments to help us see even farther beyond the boundaries of the visible world. As Hooke had giddily predicted in the preface to his Micrographia, there seems to be no limit to instrument-aided perception. Since that time new technologies have continued to extend the visible world, just like the telescopes, microscopes, and camera obscuras of the seventeenth century. The Hubble Telescope has disclosed to us the way galaxies looked eleven billion years ago. Electron microscopes can magnify up to one million times, revealing even the surface configuration of a single atom. The discovery of x-rays by Wilhelm Röntgen in 1895 allowed us to see inside opaque bodies for the first time. That such vision could be possible was almost as surprising to people as the existence of a world of microscopic creatures. With more recent imaging technologies, such as positron emission tomography (PET) scans, we can see the metabolic activity of cells in the body. Such technologies extend the visible world to realms unthinkably small, or far away, or deep inside.
The natural philosophers and the artists of the seventeenth century taught us that instruments could be used as extensions of our eyes, and that we could learn how to see with them, even if what we saw with them was not like anything we could see with the naked eye. Today’s new instruments for seeing the invisible are even further removed from the act of naked vision than were the optical instruments of Vermeer and Leeuwenhoek’s time. But by extending what it means to see, as their seventeenth-century counterparts did, today’s scientists have opened up new parts of the universe to our knowledge. Telescopes that work outside the visible light spectrum, such as infrared telescopes, radio telescopes, x-ray telescopes, and the Hubble Telescope, have been used to see the cosmos in a way very different from that of the telescopes used by Galileo. The gorgeous images from the Hubble released to the public are not photographs taken from space, as they seem to be, but are woven together from incoming data by computers, and then colorized, in order to yield a form accessible—and pleasing—to our eyes.
And today we understand, even more fully than did our forebears in the seventeenth century, that using our own visual systems requires learning to see with them. As earlier writers had suggested, and as Van Leeuwenhoek had concluded after dissecting the optic nerve of a cow and examining it with his microscope, seeing takes place not only on the retina but also in the visual centers in the brain. Using functional magnetic resonance imaging (fMRI), scientists in our time can see the brain activity that occurs when a subject is presented with visual stimuli. Powerful electromagnets measure brain activity by detecting changes in blood flow that correlate with changes in magnetic properties of blood; when an area of the brain is in use, the flow of oxygen-rich blood to that region increases, and when the area ceases its activity, oxygen-poor blood takes the place of the oxygen-rich blood.
Such studies have confirmed what Vermeer, Van Leeuwenhoek, and others of their time suspected. It is not only the employment of new technologies that requires learning to see—even the use of our natural visual system requires training. Neurophysiologists have shown that early visual experience is necessary for the development of mechanisms in the brain required for normal vision. In order to have depth perception, for example, mammals must develop the brain mechanisms to compute depth from the disparities of two visual images, one received by each eye. The brain mechanisms arise in the course of the early experience of seeing with two eyes correctly aligned. People who are born with a misalignment of the eyes—as in strabismus, or crossed-eyes—may never achieve stereoscopic vision, even if the problem is corrected later in life, because they lack that early experience. At the same time, some adults lacking stereoscopic vision have apparently been able to achieve a measure of it by diligently performing certain eye exercises every day for years—by learning how to see depth. And like Cheselden’s thirteen-year-old boy, bestowed sight for the first time after cataract surgery, the few documented cases of patients whose blindness was “cured” indicate that the journey from blindness to sight is not an easy one, and requires a great deal of work—a blind man or woman given vision still must learn to see.
As in seventeenth-century Delft, it is today not only the scientists but also the artists who are experimenting with new perceptual technology. And as in the earlier time, critics question whether it is legitimate to use technologies in creating art. The rejection of the use of painting aids expressed by Leonardo and others of his day was based on notions of “virtuosity,” that “fine art” requires only the hand—and eye—of the painter, that the use of any equipment was somehow a form of “cheating.” This view was tested in the seventeenth century by Dutch artists who began to use lenses and other optical devices to learn about how we see, and to use that knowledge to create works of art steeped in visual experience. But the opposition to the use of technology—the demand that the artist have “compasses in his eyes” and not in his hand—continued long after the time of Vermeer and persists today, seen in the resistance to the idea that painters like Vermeer might have experimented with any optical devices.
In the nineteenth century, when the photographic camera was invented
, its creator Henry Fox Talbot insisted that it was a form of art, and early photographers captured images that they modeled on the style of contemporary paintings. Yet critics of the time were slow to accept photography as a new art form, seeing it only as a new technology, a “recording” device useful for science. Technologies that have arisen more recently, such as the computer and the scanner, have been deployed to create new kinds of art. Today’s most recent innovations for seeing the world—Google Glass, 3-D imaging—are slowly entering the toolkit of artists, and undoubtedly some artists will be censured by critics unwilling to accept that technologies play a role in artistic creation. But artists—like Vermeer—have always relied upon science and technology to push the limits of their art, and they will always do so, especially when science opens up a new way of seeing the world.
EPILOGUE
Dare to See!
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ON THE FRONTISPIECE of the final collection of Van Leeuwenhoek’s letters published in his lifetime, we find a curious vignette. A man climbs a mountain whose summit is crowned with an overflowing cornucopia, representing knowledge. He is being helped to the top by a winged god holding a scythe—a common symbol for Time. As the motto for the image and his book Van Leeuwenhoek chose the phrase Dum audes, ardua vinces—When you dare, you will conquer the steep, as the usual translation has it. The intended meaning is clear: If you but dare, you will be rewarded with knowledge.
The idea that acquiring knowledge required audacious feats had roots that reached back to the beginning of the seventeenth century. In a 1618 emblem book—one of those illustrated didactic texts circulating around Europe in the sixteenth and seventeenth centuries—the Dutch lawyer Florentius Schoonhovius chose to encircle a portrait of himself with the words Sapere aude, Dare to know. But in Schoonhovius’s volume, as in other emblem books of the time that used the phrase, daring to know was tempered by another motto, Altum sapere periculosum—It is dangerous to know high things—a warning against entering into religious controversies. Dare to know, then, but only within certain limits. This simultaneous encouraging and constraining of audacity could not last. Soon enough, Sapere aude became an exhortation to overcome constraints and come to know everything. Pierre Gassendi, French priest, mathematician, and philosophical sparring partner of Descartes, adopted it as his own personal slogan. Fifty years after Van Leeuwenhoek’s death, the philosopher Immanuel Kant used the motto both to define and to capture the spirit he called “Enlightenment (Aufklärung).”
Eye of the Beholder: Johannes Vermeer, Antoni van Leeuwenhoek, and the Reinvention of Seeing Page 36