International Society for History, Philosophy, and Social Studies of Biology

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TUESDAY, JULY 7  /  09:00 - 10:30  /  DS-M320
Organized session / standard talks
The quest for affinity: Four pre-Darwinian views of nature

Aleta Quinn (University of Pittsburgh, United States); Aaron Novick (University of Pittsburgh, United States)

“I confess that this question as to the nature and foundation of our scientific classifications appears to me to have the deepest importance, an importance far greater indeed than is usually attached to it,” Louis Agassiz wrote. We fully agree. That Darwinism did not put the question to permanent rest is shown by the bitter debates within systematic biology in recent decades. Appeals to philosophy and to history feature in these debates, but historians and philosophers have not yet responded adequately to this opportunity. For example, historians trace the concept of homology back to Richard Owen's definition, but Owen acknowledged his debt to the taxonomic concept of affinity. Never synonymous with similarity, this subtle and influential concept rose to prominence in Britain when William Sharp Macleay placed it at the heart of his quinarian system. Macleay’s circular diagrams, though well-known to historians, remain poorly understood. Most taxonomists were notoriously unreflective about the theoretical basis of their work, but Macleay was an exception, as was his one-time admirer George Waterhouse and his articulate opponent Hugh Strickland. Across the Atlantic, Charles Girard, apostate student of Agassiz, also strove to make explicit his ideas on affinity. The writings of these four men demand from us careful and sympathetic reading, avoiding anachronism – but not only their writings, for they also conveyed their thoughts through diagrams. We must examine their various images with the same careful attention we give to their words, but should we also keep in mind the meanings assigned to diagrams by systematists today?

On the origins of the quinarian system

Aaron Novick (University of Pittsburgh, United States)

William Sharp MacLeay developed the quinarian system of classification in his Horae Entomologicae, published in two parts in 1819 and 1821. For two decades, the quinarian system was widely discussed in Britain and influenced such naturalists as Charles Darwin, Richard Owen, and Thomas Huxley. This paper offers the first detailed account of MacLeay’s development of the quinarian system. I show that MacLeay had two primary motivations in developing his system: (1) to reconcile the continuity of organic nature with the failure of linear classification schemes, and (2) to overcome what he perceived as dogmatism and indolence on the part of British Linneans. The paper also argues against two myths widely accepted in the historiography of the quinarian system: (a) that MacLeay developed his system as a modification of Lamarck’s twin series, and (b) that the quinarian system was an “idealist” system of classification.

Comparing Strickland's chart of bird affinities to Waterhouse's circles of mammals

Mary P. Winsor (University of Toronto, Canada)

In 1843 Hugh Strickland created a huge chart on which hundreds of genera of birds are linked to one another as a vast network. He unrolled this remarkable object at the annual meeting of the British Association for the Advancement of Science, held that year in Cork, Ireland. At that same meeting George Waterhouse presented a diagram of ten circles representing the orders of mammals. Strickland judged Waterhouse's project as similar to his own, even though major differences are obvious to us. Macleay's distinction between affinity and analogy, and his diagrams, had greatly influenced both men. Although all these naturalists rejected transmutation, for a 21st century historian to examine their diagrams without reference to evolution would be a foolish restriction.

Circles and cones: Charles Girard's approach to the natural system

Aleta Quinn (University of Pittsburgh, United States)

In this paper I explicate Charles Frederic Girard’s theory and method of natural classification. A student of Agassiz, and subsequently (1850-1858) a collaborator with Spencer Baird, Girard claimed that natural classificatory methods do not presuppose either a special creationist or a developmentalist theory of the natural world. The natural system, Girard claimed, comprises three distinct ways in which organisms can be related to each other: affinity, analogy, and height. Girard analyzed these relationships, and justified his classificatory methodology, by appeal to his embryological and physiological work. Girard offers an explicit theoretical answer to the question, what characters are evidence for natural classificatory hypotheses? I show that the challenge of simultaneously depicting the three distinct types of relationship led Girard to add a third dimension to his classificatory diagrams.