Erik L. Peterson

The concept of admixture is currently widely being used, both in population genetics research and in DNA ancestry testing discourse. It is assumed to describe the process of gene flow between 2 previously distinct populations that eventually become admixed because of this flow. The concept per se does not require pure or unadmixed populations; the changes are relative and what matters is the level of admixture before and after the event under consideration. However, in this paper, we argue that the concept of admixture as currently used assumes the existence of pure or unadmixed categories. These do not need to have actually existed but to be able to exist in principle. We argue that this is a problematic notion that accrues from the racialist origins of the term admixture, which, as a result, is based on assumptions about purity. We suggest that scientists should be very cautious in their use of this term, especially in science education and communication. We also suggest that the term admixture should be better replaced by terms denoting similarity rather than difference.

In his 1966 John Danz lectures, Francis H. C. Crick decried vitalism in the life sciences. Why did he do this three decades after most historians and philosophers of science regarded vitalism as dead? This essay argues that, by advocating the reduction of biology to physics and chemistry Crick was: (a) attempting to imbue the life sciences with greater prestige, (b) paving the way for bioengineering and the reduction of consciousness to molecules, and (c) trying to root out religious sentiment in the life sciences. In service of these goals, Crick deployed vitalism as a straw man enemy. His wave of so-called vitalists in the middle of the twentieth century in fact raised legitimate questions regarding the relationship of organisms to their DNA molecules that Crick was ill-equipped to answer. Moreover, most were not vitalists at all but advocates for what I term bioexceptionalism—an argument for the methodological utility of keeping biological pursuits within their own domains, distinct from physics and chemistry, regardless of the ontological status of living things. Nevertheless, Crick’s status as a “cross-worlds influencer” entrenched a philosophically-enervated reductionism in the life sciences for decades.

We may induce from a longue duree examination of Anglo-American History of Biology that the impulse to reject reductionism persists and will continue to percolate cyclically. This impulse I deem "bioexceptionalism": an intuition, stance, attitude, or activating metaphor that the study of living beings requires explanations in addition to exclusively bottom-up causal explanations and the research programs constructed upon that bottom-up philosophical foundation by non-organismal biologists, biochemists, and biophysicists - the explanations, in other words, that Waddington (1977) humorously termed the "Conventional Wisdom of the Dominant Group, or cowdung." Bioexceptionalism might indicate an ontological assertion, like vitalism. Yet most often in the last century, it has been defined by a variety of methodological or even sociological positions. On three occasions in the interval from the late nineteenth century to the present, a small but significant group of practicing biologists and allies in other research disciplines in the UK and US adopted a species of bioexceptionalism, rejecting the dominant explanatory philosophy of reductionistic mechanism. Yet they also rejected the vitalist alternative. We can refer to their subset of bioexceptionalism as a "Third-Way" approach, though participants at the time called it by a variety of names, including "organicism." Today's appeals to a Third-Way are but the latest eruption of this older dissensus and retain at least heuristic value apart from any explanatory success.

Historians and biologists identify the debate between mechanists and vitalists over the nature of life itself with the arguments of Driesch, Loeb, and other prominent voices. But what if the conversation was broader and the consequences deeper for the field? Following the suspicions of Joseph Needham in the 1930s and Francis Crick in the 1960s, we deployed tools of the digital humanities to an old problem in the history of biology. We analyzed over 31,000 peer-reviewed scientific papers and learned that bioexceptionalism participated in a robust discursive landscape throughout subfields of the life sciences, occupied even by otherwise unknown biologists.