Evolution by the Numbers. James Wynn

in a particular historical period is not, to my knowledge, a method that has been previously exploited by rhetoricians of science. Current rhetorical work analyzing scientific argument relies either on a scientific figure’s knowledge of rhetoric or on second-hand accounts of the conventions of scientific argument. In Jean Dietz Moss’s work on the Copernican controversy, Novelties in the Heavens, for example, Moss offers readers historical evidence that scientific figures such as Galileo and Kepler had studied and/or taught rhetoric. This evidence proves a particular connection between rhetorical treatises and a scientist’s use of characteristically rhetorical strategies of argument—such as the employment of ornamental language to gain the attention and admiration of the reader. While this approach offers a robust connection between specific rhetorical training and argument, it limits the rhetorical analyst to cases in which scientists can be proven to have had a rhetorical education. Though these limitations are not prohibitive in investigations of Renaissance science, they become severely restrictive for science in the nineteenth century—a time when rhetoric was largely absent from standard education and during which no new substantive treaties on rhetoric were published (Houlette ix). Further, by restricting rhetorical investigations to facets of argument learned through a rhetorical education, the range of scientific argument that can be explored is unnecessarily narrowed based on distinctions between dialectic and rhetoric, which are practically very difficult to maintain.

      Other rhetorical analysts of science have adopted a broader sense of the argumentative territory open to rhetorical discussion and analysis. However, in their efforts to identify the conventions of scientific argument, they depend on secondary rather than primary sources. In Lawrence Prelli’s substantive work on the rhetoric of science, A Rhetoric of Science: Inventing Scientific Discourse, for example, he relies on Thomas Kuhn’s discussions in The Structure as the source for his problem-solution topoi and evaluative topoi.3 Though Kuhn is certainly considered a reputable source for understanding scientific argument, neither he nor Prelli offer any primary source evidence to corroborate that scientists endorsed these lines of reasoning as conventional places for finding arguments in science.

      The methodological contribution of this book is in its use of primary source material, specifically the writings of nineteenth century philosophers of science, as sources for constructing a robust description of the conventions for arguing with mathematics during this period. By relying on primary source material, it avoids problems of reliability and contextual sensitivity. In addition, it broadens the scope of materials available to rhetoricians for analyzing scientific argument and offers a means by which the division between common and special lines of argument can be made. These divisions are formulated positively based on examinations of the actual conventions articulated by a scientific discourse community rather than negatively as anything not existing in a particular treatise or set of treatises on rhetoric. Investigating the articulated conventions of science in conjunction with scientific arguments provides a broader and more accurate picture of what constitutes or does not constitute a common or special line of argument, and thereby what aspects of scientific argument are or are not being employed rhetorically.

      Close Textual Analysis

      While the historical analyses in the book are aimed primarily at establishing the conventions for mathematical and scientific argument, close textual analyses of the works of featured arguers offer insight into their specific choices of language, organization, and argument. These choices illuminate not only the persuasive goals and strategies of arguers, but also what these arguers may have believed about their audiences.

      This type of analysis is conducted in this investigation using a number of pre-existing analytical categories in modern and classical rhetoric, such as ethos, stases, loci, value hierarchies, etc. as well as a detailed assessment of choices in language, organization, and argument in the text. The applications of these analytical categories are intended—in addition to their utilitarian function of illuminating the character and structure of the argument—to illustrate that categories for analyzing discourse and argument exist within rhetoric that might be profitably used to expand our understanding of the role of mathematics in scientific argument.

      Audience Response Analysis

      Finally, unlike the two previous analytical methods, which are primarily designed to illuminate argument conventions and strategies, the third method, audience response analysis, is designed to provide insight into persuasion. As some rhetoricians have pointed out, rhetorical analysts have made bold pronouncements about the persuasive affects of texts without supplying evidence from the audience to support their contentions.4 The analysis in this book endeavors to make claims about the reasons that late nineteenth and early twentieth century biological researchers judged mathematical concepts and formulae to be reliable or unreliable grounds for arguments about variation, evolution, and heredity. As a consequence, it is necessary not only to discuss the conventions of scientific argument, but also the specific reasons given by audiences for accepting or rejecting them.

      Examining the responses of individual audience members in conjunction with the conventions of scientific argument has a number of benefits. First, by examining the two together, it is possible to know whether members of a particular audience were or were not appealing to convention to support their praise or excoriation of a scientific argument. This knowledge provides a method of checking whether scientific conventions were taken seriously, considered unreasonable ideals, or not considered applicable in particular situations. Second, by examining individual responses it is possible to understand whether sources of good reasons for accepting or rejecting mathematical argument were limited to the conventions outlined in scientific philosophies. If alternative good reasons exist, their presence suggests that there may be values, beliefs, and truths from outside the confines of a specific scientific discourse community impacting the development of scientific knowledge. Their existence would indicate that broader, rhetorical lines of argument are implicated in reasoning about the validity of mathematical warrants in making scientific arguments about biological phenomena.

      To make claims about what audiences might have thought about a particular application of a mathematical argument to some aspect of variation, evolution, and heredity, each chapter includes close readings of audience responses to the texts of the featured arguers. These responses are primarily from book reviews written at or around the time a featured text was released or, in the cases of journal articles, private or public responses offering commentary on the research. All audience responses are assessed by close textual analyses, singling out the reasons given by respondents for supporting or challenging the featured arguments. In addition, the reasons are compared to the featured arguer’s theory of his audience to draw conclusions about why they may have succeeded or failed in their persuasive endeavor.

      Preview of Chapters

      Each chapter in the book is dedicated to investigating some aspect of the relationship between science, mathematics, and argument. In the first three chapters, the focus is on articulating the general conventions and limitations of mathematical argument in science. The remaining three chapters explore the rhetorical dimensions of making mathematical arguments in science.

      Chapter 2, “A Proper Science,” explores nineteenth century epistemological and ontological commitments about the appropriate relationship between mathematics and science by examining the philosophies of two of the period’s most influential, natural philosophers. A close reading of William Whewell’s, Philosophy of the Inductive Sciences (1840), and John Herschel’s, Preliminary Discourse on Natural Philosophy (1831), suggests that quantification and mathematical reasoning were considered assets in the production of knowledge about nature because they contributed precision and rigor to scientific research and reasoning. Investigations of these texts also reveal the stages in which quantification and mathematical reasoning contributed to science and the process by which mathematical arguments might be elevated from hypothetical analogies to deductive laws of nature. The views of these two, influential philosophers about the status of mathematical arguments in science provides a framework for assessing the status of mathematical arguments, the choices of arguers as they seek to defend them, and the reactions of nineteenth century audiences as they move to accept or reject mathematical arguments as a legitimate means for making knowledge about nature.

      The third chapter, “A New Species of Argument,” examines the rise of the mathematical treatment