 Both reductive and holistic immunological research agendas have vied for dominance (Silverstein 2009: 25–42). The immune-chemical program, championed by Ehrlich and other immunochemists of the first half of the twentieth century, examined immune reactions in terms of chemical and physical forces between immune receptors and their ligands (Silverstein 2009: 456). These immunochemists were adopting a “unifactoralism” strategy that endeavors to explain complex biological processes in terms of single factors (Powell and Dupré 2008). That program was modified and renewed by the elucidation of the genetics of antibody diversification, a series of discoveries that placed immunology well within the molecular biology revolution (Podolsky and Tauber 1997).