Why Was Darwin Believed? Darwin's Origin and the Problem of Intellectual Revolution

Anyone advancing a novel idea must face the "Catch 22" of intellectual change. If an idea is truly radical, how can it be understood, let alone believed? Without a shared context of assumptions, an idea cannot even be intelligible, let alone persuasive. Yet to the extent that an idea is indebted to convention, it comes into the world hostage to the older and opposed ideas necessary in order to explain it. Analogous to the logical paradox of Achilles and the tortoise, the tension between radical novelty and convention constitutes a rhetorical paradox: If conventional ideas are necessary in order to explain radically novel ones, how can novelty ever overtake convention, since to challenge convention one must, and at every step in one's argument, reinforce it?¹

Understanding the way established frameworks of ideas change is at once a conceptual, a historical, and a rhetorical problem. It is a conceptual problem because it concerns how human beings think; it is a historical problem because change occurs in and over time, is always situated in place, context, and circumstance; and it is a rhetorical problem because change occurs in and through language and requires analysis of how the polysemic potential of language, just beneath the surface of convention, is activated and deployed.²

How the potential of language to facilitate or impede intellectual change is actualized is a question that is far from abstract. The question arises regularly in the history of ideas, from Copernicus to Chomsky.³ It represents a recurrent practical problem faced by movements for social change, from the abolitionists to the advocates of civil rights, women's rights, and gay rights; or, more mundanely, it recurs whenever, as teachers, parents, colleagues, and friends, we try to explain something that, to our interlocutors, seems challenging, strange, or beyond the pale.

The dynamic of how to either facilitate intellectual change or impede it was first articulated by the Sophists. Protagoras, arguably the greatest of these, set forth the core of what was then a novel social practice when he articulated his pair of famous sayings: that every issue of concern to humans has at least two sides, and its seemingly infamous corollary, that the business of the art of words is to make the weaker case appear the stronger and vice versa.⁴ Modern psychology, according to Michael Billig, is largely a matter of footnotes to Protagoras. Billig finds in Protagoras the key insight that human perception owes less to psychological laws hardwired into our psycho-physical being and more to our capacity to argue and deliberate.⁵ Protagoras's weaker case, as Billig and others note, is not, in the first instance, to be understood as an invitation to charlatanism. Placed in historical and situational context, the weaker case may be no more, or less, than a new idea that challenges strong perceptual prejudices or habits.⁶ Jeanne Fahnestock's recent book has reinforced the cognitive importance of the insights of Protagoras and Billig through her explication of how the schemata of traditional rhetorical figures function, even in science, not merely to delight but also to refigure and change thought.⁷ Examining the contextual, literary, and expository strategies of science continues to be a major focus in the work of Gillian Beer, Janet Browne, James Secord, Martin Rudwick, Peter Dear, Marcello Pera, Charles Bazerman, Larry Prelli, Allan Gross, Leah Ceccarelli, and the burgeoning literature in the rhetoric of science.⁸ At the very center of the challenge of intellectual change as a rhetorical problem is the concept of ethos. As Eugene Garver has powerfully argued following Aristotle, argument reveals character and, even where logic seems the chief or only factor in play, ethos may be decisive in determining whether an argument is believed.⁹ Greg Meyers's work on grant-writing and journal-refereeing documents the importance of ethos even in the midst of...