How can an English bishop and a French évêque help Darwin explain his theories about species and natural selection?
In the middle of the nineteenth century, linguists were concerned with establishing genetic relationships between the English language and cognates (words that have a common etymological origin) in various other Indo-European languages.
Hensleigh Wedgwood , Emma Darwin’s brother and Charles’ cousin was a philologist, barrister and original member of the Philological Society, which had been created in 1842. In 1857, while Wedgwood was preparing a dictionary of English etymology, he wrote to Darwin suggesting that the common origin of the French “chef” and the English “head” and “bishop” illustrated the parallels between extinct and transitional forms in language and palaeontology.
Hensleigh’s cousin must have appreciated the comparison, for he used the case of ‘bishop’ and evêque’ in a chapter about the difficulties presented by his theory in Natural selection, in order to show how apparently dissimilar animals could be derived from a common source, just like etymology could show words to be : “to one who knew no other language, dead or living, besides French & English, how absurd would the assertion seem, that evêque & bishop had both certainly descended from a common source, & could still be connected by intermediate links, with the extinct word episcopus.”
Charles Darwin dropped the bishops, but used the analogy again in Origin, and eventually in the in the Descent of Man, where he wrote soberly that “the formation of different languages and of distinct species and the proofs that both have been developed through a gradual process are curiously the same.”