Science and wonder have a long and ambivalent relationship. Wonder is a spur to scientific inquiry but also a reproach and even an inhibition to inquiry. As philosophers never tire of repeating, only those ignorant of the causes of things wonder: the solar eclipse that terrifies illiterate peasants is no wonder to the learned astronomer who can explain and predict it. Romantic poets accused science of not just neutralizing wonder but of actually killing it. Modern popularizations of science make much of wonder—but expressions of that passion are notably absent in professional publications. This love-hate relationship between wonder and science started with science itself.

Wonder always comes at the beginning of inquiry. “For it is owing to their wonder that men both now begin and at first began to philosophize,” explains Aristotle; Descartes made wonder “the first of the passions,” and the only one without a contrary, opposing passion. In these and many other accounts of wonder, both soul and senses are ambushed by a puzzle or a surprise, something that catches us unawares and unprepared. Wonder widens the eyes, opens the mouth, stops the heart, freezes thought. Above all, at least in classical accounts like those of Aristotle and Descartes, wonder both diagnoses and cures ignorance. It reveals that there are more things in heaven and earth than have been dreamt of in our philosophy; ideally, it also spurs us on to find an explanation for the marvel.

Therein lies the paradox of wonder: it is the beginning of inquiry (Descartes remarks that people deficient in wonder “are ordinarily quite ignorant”), but the end of inquiry also puts an end to wonder. The marvel that stopped us in our tracks—an aurora borealis, cognate words in languages separated by continents and centuries, the peacock’s tail—becomes only an apparent marvel once explained. Aesthetic appreciation may linger (it is no accident that the vernacular descendants of the Latin word for wonder, admiratio, convey esteem), but composure has returned. We are delighted but no longer discombobulated; what was once an earthquake of the soul is subdued into an agreeable frisson. At least within the classical philosophical tradition, from Aristotle to Descartes (and arguably beyond, to Adam Smith and even to Kant), this negative correlation between wonder and explanation is strong and tenacious. Explanation lies at the heart of the distinction between marvels and miracles in the Latin Christian tradition. What is the difference? Thomas Aquinas answers: marvels (mirabilia) are inexplicable to most but not all people (e.g. the eclipse that transfixes the ignorant peasant but not the learned astronomer); miracles (miracula) are inexplicable to everyone. Wonder is a barometer of ignorance: the learned experience it rarely; God, never. Wonder is not only a peculiarly human passion; it is also one that, at least on this account, underscores the limits of human knowledge. The more we know, the less we wonder.

This is why wonder was long considered to be a passion at once necessary but ultimately unbecoming to any seeker of knowledge, second only to fear, to which it was closely akin, as a badge of dishonor. Striking a balance between just enough and too much wonder became something of an obsession with early modern philosophers, especially those, like Bacon and Descartes, who were intent on reforming the foundations of natural science. Descartes admitted that wonder was the essential stimulus to inquiry, but fretted that the stimulus could easily become an addictive drug. Excessive wonder (admiration) could slide into astonishment (étonnement), thereby arresting rather than triggering the quest for explanation. Astonishment, he wrote, “makes the whole body stay immobile like a statue, so that one is unable to perceive any more of the object than the first face presented, nor can one consequently acquire further knowledge of it.” A little wonder worked like caffeine upon the mind; too much, more like morphine.

Bacon was similarly ambivalent. On the one hand, he called for the creation of a whole new branch of natural history that would supplement the study of ordinary nature with extraordinary nature: “the errors, vagaries and prodigies of nature, wherein nature deviates and turns aside from her ordinary course.” The purpose of this motley collection of all that was “new, rare and unusual” was to chasten rather than to charm. These anomalies would serve as a standing reproach to an Aristotelian natural philosophy unable to deliver explanations of them. Bacon took a dim view of wonders collected simply to please, whether purveyed in books with beguiling titles like A Thousand Notable Things or displayed in Wunderkammern. His natural history of wonders was meant as a kind of shock therapy to complacent natural philosophers content to study what happens always or most of the time. Yet he was just as skittish as Descartes about overdosing on wonder, which he elsewhere described as “broken knowledge.” Wonder was indispensable to inquiry, but only as the spark that ignited the process.

Like eros, wonder was once considered a dangerous passion. Much of the traditional intellectual ambivalence surrounding wonder derived from its affinity to the passions of horror and terror. For us moderns, this link has gone underground, so some excavation is required to make them plausible. Modern wonder, like many of the traditional passions, has faded from the saturated hues of blood red and lapis lazuli blue to baby pink and blue pastels. “Baby” is used advisedly in this context: modern wonder has become infantilized, the stuff of children’s entertainment, whether in the form of cartoon fairy tales or science museum exhibitions. Perhaps drawing on wonder’s ancient associations with ignorance, modern wonder-mongers address themselves to children or to “the child in all of us.” In contrast, premodern wonder was as powerful as dynamite, and just as dangerous. Like anger, wonder has traced a decay curve of declining intensity since Descartes, from passion to emotion. Passions in the original sense of the word (from the Greek pathema, the Latin passio) are things that we suffer like an illness (“patient” and “passions” share the same root), things that befall rather than move us, not so much states as sieges of the soul. In contrast to the emotions, first conceived in the eighteenth century as movements in the nerves and brain, or the still more delicate sentiments and feelings, passions don’t belong to us; we belong to them.

Wonder, horror and terror constitute a trio of passions that has survived the reconceptualization of affect since the late seventeenth century in the works of Descartes, Hume, Adam Smith, Kant, Rousseau, Darwin, William James and many others. This trio is unusual in at least three respects. First, all three contain a distinctly cognitive component. In order to feel horror, terror or wonder, one must first register an anomaly: these are the observant passions, which pick out the extraordinary against the background of the ordinary. Second, although all three deserve to be called vehement with respect to their intensity, they are not single-minded. The perceived anomalies that trigger wonder or horror or terror are so far beyond the usual range of experience that doubt vies with recognition in the mind: these are the I-can’t-believe-my-eyes passions, which split the self into skeptic and believer. Third, and most important for my purposes, the anomalies that evoke this trio of passions are violations of order. They are the passions of the unnatural. Horror, terror and wonder are triggered when a major disruption of order (whether moral or natural or both) is registered as such: an act of perception and judgment that presumes some acquaintance with the particular sort of orderliness that has been breached—that, as the phrase goes, “something is not right.” Subterranean connections bind the passions of the unnatural to each other. Although, for example, horror and wonder may seem poles apart as states of experience, they are linked by deep ties, as evidenced by the strange tendency of one passion to tip over into the other—for example in responses to monsters.

Horror and terror are more obviously related to one another, but the peculiar terror evoked by natural disasters also shows revealing affinities to wonder. Despite dramatic differences in emotional texture, wonder, terror and horror all contain a moment of astonished disbelief. They are the eye-rubbing passions of incredulity: Can this really be happening? These passions form a triplet, united both by their interrelationships and by a shared tendency to blur moral and natural stimuli. They are the subjective side of the objective perception of a disorder so dramatic that even nature quakes.

Against this background, the traditional philosophical ambivalence toward wonder becomes intelligible: wonder may, like horror and terror, be triggered by an anomaly begging for rational explanation, but it can all too easily, like horror and terror, paralyze reason. That wonder always bordered on religious awe did not improve its reputation among the party of reason, whether peopled by premodern philosophers or modern scientists. Indeed the fact that naturalists since the Pre-Socratics have made precisely those phenomena most likely to evoke awe and appeals to the divine—such as thunder, eclipses and earthquakes—their primary explananda strongly suggest that killing wonder was not simply the by-product of natural inquiry; it was its aim.

Many humanists nowadays still suspect scientists of being wonder-killers. They echo Romantics like Wordsworth, who complained about the kind of natural philosopher (the word “scientist” was not introduced into English until the 1830s) who would “peep and botanize / Upon his mother’s grave,” or the melancholy anti-modernism of a whole gaggle of twentieth-century social thinkers, most of them Central European, who equated the rise of scientific and technological rationality (which they rarely bothered to distinguish) with “disenchantment” (Max Weber), loss of a cozy Lebenswelt (Edmund Husserl), or “the disappearance of the cosmos” (Alexandre Koyré). These elegies for a lost world spangled with marvels and hushed with the wonder of it all fly in the teeth of both historical fact and daily experience: it is popular science and science fiction that feed the modern public’s hunger for wonders, handily outselling books about the Shroud of Turin and the healing miracles of Lourdes. But perhaps all these wonders of popular science are just that: wonders for popular consumption. What about the actual doing of science? In this context, wonder has undergone three major transformations.

First, wonder is strongly associated with hoi polloi, at least in publications. Whereas exclamations of wonder were quite common in works of astronomy and natural history and not unknown in philosophy and philology throughout the eighteenth and early nineteenth century, they are increasingly scarce thereafter. The professionalization of the scholar and scientist as salaried university professors during this period has long been associated with the rise of ostentatious sobriety and the cult of expertise. The association of wonder with ignorance, and still more with the ignorance of children, accorded ill with both. Yet wonder never vanished from the writings of scientists and scholars: like the return of the repressed, it overflows from the pages of their autobiographies and memoirs, not just their popular books addressed to a mass audience. Albert Einstein’s anecdote about the two wonders of his childhood that steered him toward a scientific career, the magnet and Euclidean geometry, is typical of the genre.

Second, the nature of what counts as wondrous has changed, in this case already in the early Enlightenment. Einstein’s two wonders are emblematic of wonders before and after. Since Antiquity the lodestone has been part of the canon of wonders—and its mysterious powers of attraction and repulsion threw down the gauntlet to natural philosophers to come up with a sturdy explanation. But Euclidean geometry, although almost as ancient, most certainly did not qualify as one of Bacon’s prodigies, despite the fact that it was roundly and resoundingly admired by early-modern savants from Galileo to Spinoza. What Einstein marveled at was the harvest of surprising conclusions derived from so few and such self-evident premises: the wonder did not cry out for explanation; the wonder was the explanation. The transfer of wonder from the beginning to the end of inquiry was already well underway by the mid-eighteenth century, which celebrated Newton’s magisterial synthesis of celestial and terrestrial mechanics as the achievement of a demigod, and had become a fait accompli by the time Darwin published On the Origin of Species in 1859, the final pages of which also invoked the wonder of “this view of life.” (The humanities were by no means devoid of such epiphanies, e.g. the reconstruction of the family tree of Indo-European languages, the inspiration for Darwin’s similar tree-like diagram of modification with descent in the Origin.) What merited wonder in all these cases was a synthesis that unified apparently disparate phenomena within a single explanatory scheme—the tides and the orbits of the planets; oviparous birds and oviparous dinosaurs; Sanskrit and Latin. Wonder was the fruit, not just the seed of inquiry, the too-good-to-be-true surprise that so many apparently diverse things could all be explained so economically.

Third, the complexion of wonder paled. I have already sketched the trajectory of wonder from passion to emotion, with its consequent loss of intensity and also of menace. By the time Burke and Kant were writing on the sublime in the late eighteenth century, fear had been mostly drained from the wondrous. Kant even went so far as to make a slight tremor of fear followed by the reassurance of perfect safety a component of the sublime. Only in rare moments of existential danger, usually in connection with devastating hurricanes, volcanoes or other natural disasters, does wonder assert itself at full strength, once again reunited with its boon companions horror and terror. But for the most part, modern wonder has lost its power to terrify, and with it, much of its power tout court. Modern museum reconstructions of Renaissance princely Wunderkammern do capture their delightful hodge-podgery—the stuffed crocodile next to the cherrystone carved with a thousand faces next to a nautilus shell garlanded in gold—but they cannot recapture the politics of shock and awe with which the Hapsburgs in Prague or the Sforzas in Milan hoped to cow diplomats and potentates visiting such collections. Modern wonder, whether evoked by an animated movie for children or by the latest NASA photographs from the Mars probe, bears approximately the same relationship to premodern wonder as the chubby cupids featured on valentines do to the Eros whose arrows doomed Pasiphaë and Phaedra to impossible loves. It no longer requires the full armamentarium of philosophy to combat such a tame creature.

What consequences do these transformations of wonder have for inquiry? First, they have affected the sciences and the humanities in almost equal measure. If anything, humanists are even more chary of expressing wonder in their scholarly publications or even their popular ones. To do so flirts with vulgarity, even kitsch. Second, although wonder, or at least a certain raised eyebrow surprise, may still initiate inquiry, scholars and scientists reserve their mingled wonder and admiration for the outcome. Third, in contrast to the copious, various aesthetic of the Wunderkammer, wonder now accrues to revelations of deep unity underlying apparent miscellany. Wonder is now not only reserved for the end of inquiry; it is evoked by almost the opposite stimuli. The end of inquiry is no longer to make wonder stop, but to let it begin.

Art credit: Frans Francken II, Kunst- und Raritätenkammer, 1636