Argument within a Scientific Debate: The Case of the DRD2 A1 Allele as a Gene for Alcoholism.

In April 1990, Kenneth Blum and his colleagues at the University of Texas Health Science Center and the University of California at Los Angeles reported an important finding in the study of the etiology of alcoholism. They found a statistically significant association between the presence of the A1 allele(1) of the [D.sub.2] dopamine receptor (DRD2) gene and the presence of alcoholism and the absence of the DRD2 A1 allele and the absence of alcoholism in the brain tissue of 70 subjects equally divided between the two groups (Blum et al., 1990). Blum found that this association was especially strong in individuals with the most severe cases of alcoholism. This report set off a "flurry in the media" (Holden, 1991, p. 163), as a promising advance in isolating the genetic cause of alcoholism. However, in December 1990, Annabel Bolos and her colleagues at the National Institute on Alcohol Abuse and Alcoholism reported on a study of 40 alcoholics, 127 controls and 2 families which failed to support Blum's finding (Bolos et al., 1990). Since then, a number of studies have tried to replicate Blum's results, some successfully and others unsuccessfully. In 1993,Joel Gelertner and his colleagues at Yale University and the University of Connecticut Medical School analyzed all of these studies and concluded that "no physiologically significant association between the A1 allele of the DRD2 (the [D.sub.2] dopamine receptor) and alcoholism has been proved" (1993, p. 1677). The debate among the scientists studying this genetic component of alcoholism is the subject of this paper. The outcome of this debate is important for the medical community. Identification of a gene or genes that are responsible for the development of alcoholism may "lead to new pharmacological treatments, and to the development of tests combining biological and psychological indicators to predict individuals at risk for alcoholism and other addictions" (Holden, 1991, p. 164). Theoretically, individuals could take a blood test to determine whether or not they are susceptible to alcoholism and adjust their drinking accordingly. Such predictive tests would benefit the "28 million American children of alcoholics who are potentially at risk for this disease" (Blum et al., 1990, p. 2059). We examine sixteen articles published in scientific journals from 1990 through 1993 that comprise this debate. Included in our analysis are original research reports, letters to the editor, and editorials. In what follows, we first discuss the nature of scientific debate and argumentation and then examine the major issues of this debate. SCIENTIFIC DEBATE AS DELIBERATIVE ARGUMENTATION Many believe that science offers "hard, objective truth: truth as correspondence to reality, the only sort of truth worthy of the name" (Rorty, 1987, p. 38) and, therefore, is beyond the scope of rhetorical study. However, an important aspect of science is rhetorical. Scientists need to persuade each other of the merits of their research to receive grant money, they need to persuade a journal's editorial staff of the merit of their work for publication, and they need to persuade the general scientific community of the accuracy and worthiness of their findings. This last rhetorical aspect of science is the focus of this analysis. Lyne (1990) wrote of the existence of argument within the scientific community: The natural and social sciences have well-advertised methods for securing knowledge, such as statistics or laboratory procedures and so it is sometimes forgotten that scientists also need to "make their case" when they write for their peers and for others. They have in common with human sciences the need to construct arguments. (p. 179) Campbell (1987) concurred, indicating that "even scientific discourse must be persuasive to rescue from insight indifference, misunderstanding, contempt or rejection" (p. 69). A scientist who presents research findings in an unpersuasive manner risks having his or her research rejected by the scientific community. …