General Recommendation: Full Accept

Overall Summary and Thoughts:

This thrilling paper deserves publication almost as is, apart from a few minor niggles, and deserves wide promotion, since it merits and is likely to generate unusual attention.  

In 1945 Vladimir Nabokov, working at Harvard’s Museum of Comparative Zoology, casually, in a seemingly fanciful and throwaway manner, proposed a hypothesis about the origins and evolution of the American representatives of the butterflies known as the Blues. He suggested that they evolved from Eurasian forebears, coming across what are now the Bering Straits, in successive waves millions of years ago. Ignored for more than half a century, his hypothesis was vindicated in every respect in a trio of papers in 2011. Johnson and Blackwell show the reasoning that Nabokov did not provide for his incidental and apparently offhand hypothesis, confirming that it was much more than a lucky guess: it arose from his observations and inspired intuitions about the phylogenetic characteristics of a range of Holarctic, Nearctic and Neoptropical Blues, which he was able to infer, despite having only meager samples at his disposal, from the diagnostically crucial genitalia. 

When the 2011 papers received a good deal of media notice, some grouched that the findings would not have garnered such nattention without Nabokov’s prior literary fame. True enough, but no reproach. The findings showcase the power of evolution not only to explain the present but to describe and explain the past with ever-new depth and precision, and the fruitful emergence and convergence of techniques and theories available only long after Nabokov’s proposal. 

The paper surveys the reception of Nabokov’s 1940s researches on the Blues, especially the Latin American Blues: mostly neglect, for some decades, before providing a fertile stimulus to new researchers in the 1980s and 1990s with new opportunities for field work and new techniques and new conceptual tools, before their work in turn drew the attention of Harvard’s Naomi Pierce in the early 2000s to Nabokov’s conjecture and the modern possibilities of testing each part of his proposal (genera or species, relationships, sequences, timing) and the working out of a new concept, thermal filtration.   

Johnson and Blackwell then explain the scattered evidence in Nabokov’s published and unpublished work for arriving at his hypothesis, which, because it was incidental to his focus on the modern taxa in this superfamily, he did not spell out with detailed reasoning.  

The paper works on a number of levels: (1) as a reappraisal and further expansion of Nabokov’s singular achievement as a lepidopterist, an achievement particularly rare, given his primary focus for most of his life on literature, in this age of increasing specialization; (2) as a clarification of the kinds of evidence just coming in to view through the genitalic dissection that Nabokov helped extend, and then later waves of evidence, in the conceptual clarifications of cladistics and the establishment of phylogenetic relationships through DNA analysis, in paleoclimatic and paeloecological research, and in the findings of molecular clocks; and (3) as an example of the history of science, showing the value of imagination and intuition in extending far beyond observation, and of the gradual discovery of means to test and possibly falsify a hypothesis that had seemed even to its proposer probably thoroughly untestable.  

This case study shows both (a) the rationality of science, including in its use of imaginative conjecture and attempted refutation, and (b) the reasons for its non-linearity, and (c) the interplay between individual effort and collective, cumulative discovery, not least through new problems activating new networks of existing or expandable results and techniques. The work could not have been done without the insider knowledge of the first author, a key player in the first major extension of Nabokov’s findings in the 1980s and 1990s, and without the second author’s awareness of Nabokov’s particular penchant as a novelist for exploring complex patterns in space and especially time.  

The paper provides a marvelous story of the growth of scientific knowledge, its gradualness and unpredictability, its interplay between individuals and fields of knowledge, and for philosophers of science it offers a neat refutation of the Lakatosian idea that scientific research programs can be determined in advance to be degenerating or progressive.  

It will be welcomed by readers of Nabokov, those interested in the relation of the arts and the sciences, students and scholars of evolution, lepidopterists, taxonomists and naturalists more generally, and  those interested in the history, philosophy, and methodology of science.

Minor details to consider:

7: Dieter Zimmer] Dieter E. Zimmer (DEZ insisted on the E. because there's also a prominent German novelist Dieter Zimmer)

9: Benyamini.] Benyamini, 

9: invation] invasion 

13: what we found is quite interesting] surely you can do better: highly revealing?  

13: because he had taken the synchronic as an analogy for the diachronic] not quite right is it? not an analogy but a decompressible clue to the diachronic? 

19: DNA analyses exist to produce a reliable phylogeny, and now we had one] DNA analyses now exist to produce a reliable phylogeny, so we could  turn to then [or: we could turn to the relationships in Fig. 1] 

27: verify/not verify] verify/falsify 

27: his random inferences] his speculative inferences [they were definitely not random] 

29: Nakokov’s] Nabokov’s 

30: “Wellsian time machine” anecdote] not an anecdote: scenario? sci-fi thought experiment? 

30: whether it was devised  based on] choose one 

32: in his publications on (North American) Lycaeides] in Nabokov’s publications on (North American) Lycaeides 

34: not always the cases] not always the case