Darwin and the Nature of Species

7. The Varieties Problem

131 Chapter 7 The Varieties Problem Given, as we have seen, that Darwin thought species are real, also that he thought varieties are incipient species, the species problem then becomes, when studying Darwin, the varieties problem. If species are real and varieties are incipient species, then varieties would have to in some sense be real too. In this chapter we shall compare Darwin’s view on varieties with those of his contemporaries. The latter topic especially is important as a preparation for the topic of the next chapter, the question of why Darwin would repeatedly define species (both taxa and category) as not real and yet treat them as real, and not only as real but moreover repeatedly and consistently employ his own implicit species concept at that. In other words, to understand Darwin’s strategy, we have to understand both Darwin and his contemporaries on the nature of varieties. A good place to begin is with two passages examined in chapter 1, in which Darwin compares different species concepts and comments on the issue. In a letter to Hooker (December 24, 1856) Darwin wrote I have just been comparing definitions of species . . . . It is really laughable to see what different ideas are prominent in various naturalists minds, when they speak of “species” in some resemblance is everything & descent of little weight—in some resemblance seems to go for nothing & Creation the reigning idea—in some descent the key—in some sterility an unfailing test, with others not worth a farthing. It all comes, I believe, from trying to define the undefinable. [Burkhardt and Smith 1990, 309] The analysis presented in chapters 2–6 should allow us to say what Darwin really thought about each of these criteria. Although resemblance was not everything, it was not nothing either, because of common descent. Moreover descent for Darwin was certainly not of little weight but was instead of great weight, because only through descent for Darwin were adaptations acquired, and yet common descent was not the key, as we have seen in the case of primroses and cowslips. As for sterility, it was not for Darwin an unfailing test, nor was it not worth a farthing, but instead it was a fairly reliable test of species distinctness, although it was no part of what a species is. Finally, from Darwin’s practice we can see that he did in fact have an implicit definition of “species.” The passage quoted above, therefore, is highly disingenuous. What makes this even more apparent is that Darwin does not mention Edward Blyth’s criterion, which we have seen in Chapter 4 on the topic of domestic cattle, and which we have seen in the previous chapter has proven to be of great importance to Darwin, namely, constant and distinct characters. In the next chapter we shall see how the above disingenuous passage fits with what I shall argue was Darwin’s strategy. For the present, it is useful to compare it with a highly similar passage from Natural Selection, found near the beginning of Chapter IV, the first draft of which Stauffer (1975, 92) tells us was written, according to Darwin’s Pocket Diary, from midDecember 1856 to late January 1857: . . . how various are the ideas, that enter into the minds of naturalists when speaking of species. With some, resemblance is the reigning idea & descent goes for little; with others descent is the infallible criterion; with others resemblance goes for almost nothing, & Creation is everything; with others sterility in crossed forms is an unfailing test, whilst with others it is regarded of no value. At the end of this chapter, it will be seen that according to the views, which we have to discuss in this volume, it is no wonder that there should be difficulty in defining the difference between a species & a variety;—there being no essential, only an arbitrary difference . [Stauffer 1975, 98] The similarity of this passage to the other is remarkable, and indeed it is possible that they were written on the very same day. What is especially significant for our present purpose, however, is the difference in the endings . For unlike the previous passage, Darwin in the above passage relates the issue to the difference between species and varieties, stating that there is no essential difference between them. The same claim would resurface in the Origin, where Darwin says that in his view “the term species . . . does 132 DARWIN AND THE NATURE OF SPECIES [18.219.224.103] Project MUSE (2024...