Species

The Nineteenth Century, a Period of Change 145

JOSEPH HOOKER, THOMAS WOLLASTON,

AND GEORGE BENTHAM ON LOGIC AND DIVISION

Two important writers on species, Hooker and George Bentham, were collabo-

rators, but each had a different approach. Joseph D. Hooker was one of Darwin’s

closest confidants.14 4 He was introduced into Darwin’s views on evolution as early

as the 1844 manuscript, and yet he was unable to discuss these ideas with anyone

but Darwin. When he finally was able to, after the 1858 reading of Wallace’s and

Darwin’s papers, he noted to Asa Gray that he could never

allude to his doctrine in public, & I always had in my writings to discuss the subject

of variation etc & as if I had never heard of Natural Selection—which I have all along

known & feel not only useful in itself as explaining many facts in variation, but as the

most fatal argument about “Special Creation”...^145

Hooker considered that much variation in plants was intraspecific, and that there

were far fewer actual species than were listed and that what he called its “habit”—or

general appearance and growth—was deceptive as a guide to the difference between

species and varieties. He wrote to Gray in 1856,

As to consistency with regard to species—it is a myth, a delusion ... the most consistent

men are hair-splitters—they make almost every difference specific.

In the light of Whately and the logic of division in which most had been trained,
at least implicitly, this tension is understandable. Every difference was specific, logi-
cally. The problem lay in that in natural history, specifically in botany, the line was
drawn much higher than that:

Bother variation, developement [sic] & all such subjects,! It is reasoning in a circle

after all. As a Botanist I must be content to take species as they appear to be not as they

are, & still less as they were or ought to be. [To Darwin, July 1845^146 ]

Thomas Vernon Wollaston, in his 1856 On the Variation of Species,^147 defined

species as a community of descent within which there was variation but between

which there was no gradation. Those who Hooker had called hair-splitters he called

“very hyper-accurate definers.” Nevertheless, after Darwin published the Origin,

Wollaston denied the indefinite variation that Darwin needed existed. Hooker, to

the contrary, was convinced it did. In 1853, in the introduction to his Botany of the

Antarctic Voyage volume 2, part 1, he noted that unless the systematist

14 4 (^) Stevens 1997 is an excellent source of material and overview for Hooker in particular. See also
Tu r r i l l 19 63.
(^145) Quoted in Stevens 1997, 346.
(^146) Stevens 1997, 349.
(^147) Wollaston 1856, cf. England 1997.