Olaus Worm’s original illustration of a hysterolith, or “womb stone”—actually the internal mold of a brachiopod.

  This essay is not structured as a mystery yarn, so I spoil nothing, while (I hope) enhancing the intended intellectual theme, by providing the solution up front. Hysteroliths are the internal molds of certain brachiopod shells (just as bucardites, discussed and pictured above, are internal molds of certain clamshells). Brachiopods are not closely related to clams, but they also grow shells made of two convex valves that open along a hinge located at one end of the shell, and close by bringing the two valves together along their entire edges. Therefore, if you make an internal mold by pouring plaster of Paris into the closed shell, the resulting object will look roughly like a flattened sphere, with the degree of flattening specified by the convexity of the shell. Highly convex shells can produce nearly spherical molds (as in the fat clamshells that make bucardites). Shells of lower convexity—including most brachiopods and all the groups that make hysteroliths—yield more flattened molds.

  Since molds are negative impressions of surrounding shapes, the suggestive parts of hysteroliths record features on the interior of a brachiopod shell in reverse. The slit that suggested a vulva and gave hysteroliths their name marks the negative impression of a raised and narrow linear ridge—called the median septum—that runs right down the middle of many brachiopod shell interiors, effectively dividing the valve in half. (For a clarifying analogy, think of the ridge as a knife and the slit as a cut.) The less pronounced “male” features on the other side of some hysteroliths record, in positive relief, a cylindrical groove on the shell interior that houses part of the feeding skeleton (detached from the shell itself and rarely fossilized) in some groups of brachiopods.

  By the mid-eighteenth century, paleontologists had reached a correct consensus. They knew that hysteroliths were internal molds of brachiopods, and they had even learned which kinds of brachiopods left such impressions upon their molds. They also recognized, of course, that the admittedly striking similarity with human genitalia recorded a sheer, if curious, accident with no causal meaning or connection whatsoever.

  We therefore obtain, in the story of hysteroliths, a clean, clear, and lovely example of science operating at its best, by following the canonical definition of its very being and distinctiveness—a procedure dedicated to the sweetest of all goals: the construction of an accurate piece of natural knowledge. This odyssey through two centuries and several interesting stages progresses from the puzzled agnosticism of Agricola’s first mention in 1546 toward Linnaeus’s unchallenged consensus of 1753.I certainly do not deny the broad oudine of this story. Agricola and Gesner possessed few clues for deciding among a wide range of alternatives—from the correct answer that eventually prevailed, to a hypothesis of inorganic origin by plastic forces circulating through rocks, to production by various ancient animals as a meaningful symbol that might even cure or alleviate human ailments of the genital organs. The correct answer may not have fulfilled all human hopes and uses, but hysteroliths really are brachiopod molds, and science supplied the tools for proper resolution.

  I do, however, question the usual reading of such genuine scientific progress as a simple exercise in factual accumulation through accurate observation guided by objective principles of reasoning known as the scientific method. In this familiar model, the naïveté of Agricola and Gesner arises from their lack of accurate knowledge, not from any mental failures or barriers. In this sense, these sixteenth-century scholars might well be us in miniature, with the diminution established by what they couldn’t know and we have since learned by living several centuries later and enjoying the fruits of advancing scientific understanding. But we should not so diminish these brilliant men and their interesting times. Gesner and Agricola do not rank below us; they only differed from us (while, no doubt, possessing more intrinsic “smarts” than the vast majority of us) in viewing the world from entirely divergent points of view that would be fascinating for us to comprehend.

  I particularly appreciate Bacon’s metaphor of the idols because this device can lead us toward a better appreciation for the complexities of creative thought, and the unifying similarities between the style we now call science and all other modes of human insight and discovery (while acknowledging, of course, that science presides over distinct subject matter and pursues particular goals in trying to understand the factual character of a “real” external world). Bacon argued that we must filter sensory data about this world through mental processors, and that these internal mechanisms always operate imperfectly because idols gum up the works. Discovery, therefore, arises from a complex intermeshing of these inside and outside components, and not by the accumulated input of facts from the outside world, processed through centuries by the universal and unchanging machinery of internal scientific logic.

  Gesner did not use the same criteria for decisions that we employ today, so our differences cannot be attributed to his tiny molehill of reliable facts compared with our mountain. Rather, the idols conspired in him (as they still do in us, but with different resulting blockages) to construct a distinct kind of processing machine. Science prospers as much by retuning, or demolishing and then rebuilding, such mental machinery, as by accumulation of new factual information. Scientists don’t simply observe and classify enough fossils until, one day, the status of hysteroliths as brachiopod molds becomes clear; rather, our theories about the nature of reality, and the meaning of explanation itself, must be decomposed and reconstructed before we can build a mental mansion to accommodate such information. And fruitful reconstruction requires, above all, that we acknowledge, examine, and challenge the Baconian idols of our own interior world.

  I argued at the beginning of this essay that the Baconian idols could be ordered by degree of generality. In tracing the history of this internal component to solving the problem of hysteroliths, I noted an interesting progression in the release of blockages—from the most pervasive to the most particular idol, as paleontologists homed in upon a solution over two centuries. Perhaps we must first dig the right kind of mine before we can locate any particular nugget of great price.

  1. Idols of the Tribe in the Sixteenth Century. Gesner and Agricola rediscover Pliny and the three dichotomies.

  The hysterolith story begins as long ago as the recorded history of paleontology can venture, and as deeply as one can probe into the most pervasive and general of tribal idols: our propensity to dichotomize. Pliny the Elder, the great Roman statesman and natural historian who died with his boots on in the eruption of Mount Vesuvius in A.D. 79, wrote a compendium about the natural world that survived as legions of hand copies made by monks and other scholars for more than a millennium before Gutenberg, and then became one of the most widely published books in the first decades of printing. (In the trade, books printed before 1500 are called incunabulae,or “from the cradle.”)

  Agricola and Gesner, as Renaissance scholars committed to the recovery of ancient wisdom, sought above all to assign their specimens (and vernacular names) to forms and categories mentioned by Pliny in his Natural History.In an alphabetical list of rocks, minerals, and fossils, featured in the thirty-seventh and last book of his great treatise, Pliny included a notable one-liner under letter D: “Diphyes duplex, candida ac nigra, mas ac femina”—having the character of both sexes, white and black, male and female.

  Pliny’s treatise contained no pictures, so we can hardly know what object he had meant to designate with this sparse description. But on the theme of tribal idols, I am fascinated that the first mention of a possible hysterolith features two of the most general impediments in this category: our tendency to read nature at all scales in terms of immediately familiar objects, particularly the human body, and our propensity for classification by dichotomy. Pliny, in fact, explicidy cites two of the most fundamental dichotomies in his single line: male and female, and white and black. (Later commentators assumed that Pliny’s diphyes referred to stones that loo
ked male on one side and female on the other—hence their identification with hysteroliths.)

  Moreover, we should also note the implicit inclusion of a third great dichotomy—top and bottom—in Pliny’s definition, for hysteroliths are composed of two distinct and opposite halves, a stunning representation, literally set in stone, of our strongest mental idol, expressed geometrically. Moreover, all three dichotomies carry great emotional weight both in their archetypal ideological status and in their embodiment of conventional rankings (by worth and moral status) in a hierarchical and xenophobic society: male, white, and top versus female, black, and bottom. A modern perspective that we view as far more valid, in both factual and moral terms, can only cause us to shiver when we grasp the full implication of such a multiply dichotomized classification.

  In his De natura fossilium of 1546, the first published treatise on paleontology (although the term fossil then designated any object found in the ground—a broad usage consistent with its status as past participle of the Latin verb fodere,“to dig up”—so this work treated all varieties of rocks, minerals, and the remains of organisms now exclusively called fossils), Georgius Agricola unearthed Pliny’s one-liner, probably for the first time since antiquity, and applied the name diphyes to some fossils found near the fortress of Ehrenbreitstein. A generation later, in his De rerum fossilium (On fossil objects) of 1565, Conrad Gesner first connected Pliny’s name and Agricola’s objects with the folk designations and Latin moniker—hysterolith—that would then denote this group of fossils until their status as brachiopod molds became clear two hundred years later.

  Sixteenth-century paleontology proceeded no further with hysteroliths, but we should not undervalue the achievements of Agricola and Gesner in terms of their own expressed aims. As men of the Renaissance, they wished to unite modern observations to classical wisdom—and the application of Pliny’s forgotten and undocumented name to a clear category of appropriate objects seemed, to them, an achievement worth celebrating.

  Moreover, when we note Gesner’s placement of hysteroliths within his general taxonomy of fossils, we can peek through this window into the different intellectual domain of sixteenth-century explanation, and also begin to appreciate the general shifts in worldview that would have to occur before hysteroliths could be recognized as brachiopod molds. Gesner established fifteen categories, mostly based on presumed resemblances to more familiar parts of nature, and descending in a line of worth from the most heavenly, regular, and ethereal to the roughest and lowest. The first category included geometric forms (fossils of circular or spherical shape, for example); the second brought together all fossils that recalled heavenly bodies (including star-shaped elements of crinoid columns); while the third held stones that supposedly fell from the sky. At the other end, the disparaged fossils of class 15 resembled insects and serpents. Gesner placed hysteroliths into category 12, not at the bottom but not very near the honored pinnacle either, for “those that have some resemblance to men or quadrupedal animals, or are found within them.” As his first illustration in category 12, Gesner drew a specimen of native silver that looked like a mat of human hair.

  2. Idols of the Theater in the Seventeenth Century. Animal or mineral; useful symbol or meaningless accident?

  If classic tribal idols played a founding role in setting the very name and definition of hysteroliths—their designation for some particularly salient features of female anatomy, and their description, by Pliny himself, in terms of three basic dichotomies that build the framework of our mental architecture—then some equally important theatrical idols (that is, constraints imposed by older, traditional systems of thought) underlay the major debate about the origin and meaning of hysteroliths that only began with seventeenth-century paleontology, but then pervaded the century: what are fossils?

  The view of mechanism and causality that we call modern science answers this question without any ambiguity: fossils look like organisms in all their complex details, and we find them in rocks that formed in environments where modern relatives of these creatures now live. Therefore, fossils are remains of ancient organisms. This commonsense view had developed in ancient Greek times, and always held status as an available hypothesis. But the domain of seventeenth-century thought, the world that Bacon challenged and that modern science would eventually supplant, included other alternatives that may seem risible today, but that made eminent sense under other constructions of natural reality.

  Bacon called these alternative worldviews idols of the theater, or impediments set by unfruitful systems of thought. Among the theatrical idols of seventeenth-century life, none held higher status among students of fossils than the Neoplatonic construction of nature as a static and eternal set of symbolic correspondences that reveal the wisdom and harmonious order of creating forces, and that humans might exploit for medical and spiritual benefit. A network of formal relationships (not direct causal connections, but symbolic resemblances in essential properties) pervaded the three kingdoms of nature— animal, vegetable, and mineral—placing any object of one kingdom into meaningful correspondence with counterparts in each of the other two. If we could specify and understand this network, we might hold the key to nature’s construction, meaning, and utility.

  Within this Neoplatonic framework, a close resemblance between a petrified “fish” enclosed within a rock and a trout swimming in a stream does not identify the stony version as a genuine former organism of flesh and blood, but suggests instead that plastic forces within the mineral kingdom can generate this archetypal form within a rock just as animate forces of another kingdom can grow a trout from an egg. Similarly, if various stones look like parts of the human body, then perhaps we can identify the mineral forces that resonate in maximal sympathy with the sources of our own animate being. Moreover, according to a theory of medicine now regarded as kooky and magical, but then perfecdy respectable in a Neoplatonic framework, if we could identify the vegetable and mineral counterparts of human organs, then we might derive cures by potentiating our ailing animal versions with the proper sympathies of other realms, for every part in the microcosm of the human body must vibrate in harmony with a designated counterpart in the macrocosm of the earth, the central body of the universe. If the ingested powder of a pulverized “foot stone” could soothe the pains of gout, then hysteroliths might also alleviate sexual disorders.

  The availability of this alternative view, based on the theatrical idol of Neoplatonism, set the primary context for seventeenth-century discussions about hysteroliths. Scholars could hardly ask: “what animal makes this shape as its mold?” when they remained stymied by the logically prior, and much more important, question: “are hysteroliths remains of organisms or products of the mineral kingdom?” This framework then implied another primary question— also posed as a dichotomy (and thus illustrating the continuing intrusion of tribal idols as well)—among supporters of an inorganic origin for hysteroliths: if vulva stones originate within the mineral kingdom, does their resemblance to female genitalia reveal a deep harmony in nature, or does the similarity arise by accident and therefore embody no meaning, a mode of origin that scholars of the time called lusus naturae, a game or sport of nature?

  To cite examples of these two views from an unfamiliar age, Olaus Worm spoke of a meaningful correspondence in 1665, in the textual commentary to his first pictorial representation of hysteroliths—although he attributed the opinion to someone else, perhaps to allay any suspicion of partisanship:

  These specimens were sent to me by the most learned Dr.J.D.Horst, the archiater [chief physician] to the most illustrious Landgrave of Darmstadt…. Dr.Horst states the following about the strength of these objects: these stones are, without doubt, useful in treating any loosening or constriction of the womb in females. And I think it not silly to believe, especially given the form of these objects [I assume that Dr.Horst refers here to hysteroliths that resemble female parts on one side and male features on the other] that, if worn suspended around the neck, the
y will give strength to people experiencing problems with virility, either through fear or weakness, thus promoting the interests of Venus in both sexes [Venerem in utroque sexu promovere].

  But Worm’s enthusiasm did not generate universal approbation among scholars who considered an origin for hysteroliths within the mineral kingdom. Anselm de Boot, in the 1644 French translation of his popular compendium on fossils (in the broad sense of “anything found underground”), writes laconically: “Elles n’ont aucune usage que je sçache” (they have no use that I know).

  By the time that J.C. Kundmann—writing in vernacular German and living in Bratislava, relatively isolated from the “happening” centers of European intellectual life—presented the last serious defense for the inorganic theory of fossils in 1737, the comfortable rug of Neoplatonism had already been snatched away by time. (The great Jesuit scholar Athanasius Kircher had written the last major defense of Neoplatonism in paleontology in 1664, in his Mundus subter-raneus, or Underground World) Kundmann therefore enjoyed little intellectual maneuvering room beyond a statement that the resemblances to female genitalia could only be accidental—for, after all, he argued, a slit in a round rock can arise by many mechanical routes. In a long chapter devoted to hysteroliths, Kundmann allowed that hysteroliths might be internal molds of shells, and even admitted that some examples described by others might be so formed. But he defended an inorganic origin for his own specimens because he found no evidence of any surrounding shell material: “an excellent argument that these stones have nothing to do with clamshells, and must be considered as Lapides sui generis” (figured stones that arise by their own generation—a “signature phrase” used by supporters of an inorganic origin for fossils).