The Lying Stones of Marrakech by Stephen Jay Gould

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 theother 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 creativethought, 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