“What does it mean to say that we live in a secular age?” asks Charles Taylor. One major element is the sense that humans are the only agents in the world. This “exclusive humanism,” as Taylor calls it, was made possible by “a new sense of the self and its place in the cosmos: not open and porous and vulnerable to a world of spirits and powers, but . . .‘buffered.’” In contrast, in a presecular age, “extra-human agencies” were able to act on humans, not just on their minds but also on—and through—their bodies. And these bodies were understood as both agents in themselves (the body could act against its human inhabitant) and as porous, unbounded, open to penetration by outside forces. To live in a secular age, then, is to live as a new kind of human (rational, autonomous, the only agent in the world) and in a new kind of body (bounded, buffered, immune to all but the will of human agents).

We secular moderns tend to think of the human body as an objective entity, as fairly stable over time. Indeed, we think of the human body in the singular, whereby bodies are simply multiples of this same body, and we think of the human as the stable inhabitant of this stable body. But the very conferral of objectivity and stability to the body—the notion of the body as the same across time and space, immune to the forces of history (except for the very long history of evolution)—is, in fact, an effect of history.

By contrast, in medieval and Renaissance Europe, bodies were “malleable, volatile, and transgressive,” writes political theorist Vanita Seth, their boundaries porous and fluid. The spectrum of human bodies was also much wider, and human and animal physiques could intermingle. The ranks of humans included tailed men and women, witches, giants, titans, satyrs, Amazons, Cyclopes, dog-headed Cynocephali, horse-bodied Onocentaurs, double-sexed androgynes, and “wild men” who lived like beasts. As Seth notes, these various humans were simultaneously extraordinary (in that they were a minority of humans) and ordinary (in that they nonetheless appeared with some frequency in the natural world). And in their incredible book Wonders and the Order of Nature, historians of science Lorraine Daston and Katharine Park note that the Cynocephali “were among the most widely discussed and variously described of the exotic human races.”

Many of these beings were classified by theologians, natural philosophers, and the public alike as monstrous, though there were two distinct categories of the monstrous: monstrous species, i.e., the Onocentaurs, Cynocephali, and androgynes of the world; and monstrous individuals, i.e., conjoined twins, or a child born with two heads. The former were equally thought of as marvels, understood as regular (if rare or exotic) features of a natural world full of variety that spoke, ultimately, to the infinite diversity of God’s kingdom. Monstrous births and other individual anomalies, on the other hand, were unique, supernatural, and ephemeral, dependent not so much on nature’s caprice as on the will of God. Rather than expressions of natural diversity, they were signs of God’s displeasure about human transgressions of the moral order.

What counted as human, then, was not so strictly defined as it is now, and monstrous species, like other humans and animals, were both natural and part of a complex cosmology that presumed God as its center. Importantly, as Daston, Park, and Seth note, the classificatory system of late medieval Christian theology (and natural philosophy) did not operate through the binaries of nature and culture familiar to us moderns, nor through the distinction between natural and supernatural that we are used to. Rather, the natural encompassed that which functioned in predictable ways—some regularly occurring monstrous species were therefore understood as part of nature—while the non-natural included multiple sub-classifications: the artificial, the unnatural, the supernatural, and the preternatural.

The artificial and the unnatural were attributed to human rather than non-human agency. In bringing their labor to bear on nature (say, on an oak tree), humans created artificial phenomena (an oak table). Unnatural phenomena were human-initiated acts like sodomy and bestiality that contravened the order of nature and thereby violated divine law. Thus, a hybrid individual resulting from bestiality was an unnatural horror, not a marvel. The supernatural consisted of miracles attributable to God—like the parting of the Red Sea—for only God’s agency could suspend the order of nature. The preternatural was a more complicated category. Some preternatural events were signs from God to man (e.g., monstrous births). But preternatural events could also be the work of demons, angels, human sorcerers, and, sometimes, of nature itself. The trick in figuring out how to read and respond to a preternatural event lay in determining which agent—human, divine, or other—was responsible for it.

All this underscores two important, interrelated elements of medieval and Renaissance thought: first, that there were more-than-human agents in the world, and second, that the human body was susceptible to these various external agents. Both these foundational concepts about humans and bodies changed drastically in the Classical period. If the medieval and early modern period imagined a God-centered universe in which the world and knowledge itself were thought to be divinely ordained, by the eighteenth century, man had emerged as the only subject of knowledge and the only actor capable of making and re-making the world around him. Moreover, the body ceased to have a will and agency of its own; while it retained its malleability, it did so only in reference to and through the actions of men. In other words, in the Classical Age, man (or perhaps more properly, Man) became the Subject of his world, and the world became external to Man. While God retained his place as the original Creator of the world, the divine receded from interceding in that world, and Man became the only agent capable of acting on the world, including on his own body. As a consequence, the body came to be understood as a non-agentive object—like other objects in the natural world on which Man acts—that could be made to bend to “the will of reason, the influence of pedagogy, and the possibilities of science” (Seth), all of which now emanated from Man himself. This new kind of human—not just rational and autonomous but also bounded and impermeable—is the buffered self of the secular age about whom Taylor writes, the human of the exclusive humanism in which we moderns have been raised.

What happened, then, to the marvels and monsters of a previous age? By the turn of the eighteenth century, write Daston and Park, a new crop of natural philosophers, anatomists, and other scientists had relegated the marvelous—the stories of monstrous species and extraordinary events—to the domain of the vulgar, to “febrile imagination” of the popular, uneducated masses. The human imagination came to be seen as a breeding ground for credulity and superstition and therefore a threat to civil and political authority. Stories of marvels and monsters became not just fiction but fabulation, falsehoods produced by the powerful, if sometimes credulous, human mind. Interestingly, this only underscores how agency now belonged solely to humans: through their unruly imaginations about the supposed agency of “fantastical” beings, humans became the creative agents of their own deception, but nonetheless the only forces acting in and on themselves and the world.