If Thomas Huxley earned the title of "Darwin's bulldog," then Asa Gray should be remembered as "Darwin's dove." Whereas Huxley enjoyed a good fight in his defense of Darwin's theory, Gray sought to mediate and bring sides together around a common understanding of "good science." As Darwin's strongest and most vocal scientific ally in the United States, Gray recognized the scientific importance of Darwin's efforts for the growing professionalism of biological researchers.
But as an orthodox Christian, a Presbyterian firmly devoted to the faith expressed in the Nicene Creed, Gray saw in Darwin's theory both evidence for his philosophical commitment to natural theology and support for his opposition to the idealism advocated by Louis Agassiz and the Naturphilosophen in both Europe and America. Indeed, Agassiz's advocacy of Platonic forms as a basis of biological understanding (e.g., "A species is a thought of the creator")1 would be a major source of American opposition to Darwin's theory.
Professor of botany at Harvard during most of the middle half of the nineteenth century, Gray was one of the few members of the scientific community to whom Darwin revealed his theory before the publication of On the Origin of Species, and, from what I can tell, the only American. Gray and Darwin met briefly in January 1839 during one of Gray's visits to England. Later, during the 1850s, Darwin wrote Gray on several occasions requesting information--a practice that Darwin frequently employed. In 1854, Darwin's friend and confidant, Joseph Hooker, showed Darwin Gray's review of Hooker's Flora of New Zealand, in which Gray had argued strongly against Louis Agassiz's idealism and had raised questions from his own work on the stability of species. Gray was not yet ready to deny their permanence, but hybrids and other observations were beginning to trouble him.
The next year Gray wrote a lucid and penetrating positive evaluation of Alphonse De Candolle's two-volume Géographie botanique raisonnée, a pioneering work dealing with plant geography and distribution from a statistical perspective. Hooker had sneeringly dismissed the work. In A. Hunter Dupree's authoritative biography of Gray, he describes Gray's puzzlement at Hooker's response in these terms:
Although in the long view Gray's evaluation of the epoch-making nature of De Candolle's book was more justified than Hooker's sneers, [Gray was confused by his response, for] Hooker seemed to be talking with a more comprehensive theory definitely in mind, some reason for taking his position, which he did not divulge and which his friend [Gray] did not possess.2
Darwin, however, saw in both Gray's review of Hooker's book and in his comments on De Candolle's tome that Gray was troubled by some of the same empirical data that had been bothering him. In April 1855, Darwin wrote Gray to urge that Gray update his Manual of the Botany of the Northern United States first published in 1848, and especially to address the issue of the range of Alpine plants in the United States. Specifically, he said: "Now I would say it is your duty to generalise as far as you safely can from your as yet completed work."3
Behind this request was Darwin's desire to test his impression that Gray could make a good ally. Gray passed the test, and finally, in July 1857, Darwin let Gray in on his theory of the transmutation of species. Gray was never an uncritical supporter, and there are many evidences in the correspondence between these two scientists that Gray was willing to challenge Darwin and disagree with some of his conclusions. Nevertheless, Gray saw the importance of Darwin's work and the ways in which it provided answers to the troublesome issues that he had confronted in his own botanical efforts.
Gray responds to Darwin's theory
After considerable interchange--one might even say debate--among Gray, Darwin, and Hooker, Gray wrote to Hooker in October 1859 (one month before the publication of On the Origin of Species) saying that he had absolutely no problem with cognate species arising by variation. He did, however, raise a concern that would be the source of much future discussion. He wondered about Darwin's "carry[ing] out this view to its ultimate and legitimate results,--how [do] you connect the philosophy of religion with the philosophy of your science." He added: "I should feel uneasy if I could not connect them into a consistent whole--i.e., fundamental principles of science should not be in conflict."4
When Origins was published, Gray wrote a clear, positive, yet critical review in The American Journal of Science. Aware of mounting religious opposition, he ended his review by arguing that whereas one could use Darwin's theory in support of an atheistic view of Nature, one could use any scientific theory in that way. He wrote: "The theory of gravitation and ... the nebular hypothesis assume a universal and ultimate physical cause, from which the effects in nature must necessarily have resulted."5 He did not see the physicists and astronomers who adopted Newton's theories as atheists or pantheists, though Leibniz earlier had raised such reservations. And a similar situation existed with the origin of species by natural selection. Darwin, Gray continued: "merely takes up a particular, proximate cause, or set of such causes, from which, it is argued, the present diversity of species has or may have contingently resulted. The author does not say necessarily resulted."6
This far Gray could go with Darwin. But there was a point at which he parted company, and that was the fortuitous randomness of the process that Darwin's theory seemed to imply.
In part 2, Dr. Miles describes Darwin's struggle with the problem of natural evil and design in nature.
1. Cited in A. Hunter Dupree, Asa Gray: American Botanist, Friend of Darwin (Baltimore: The Johns Hopkins Press, 1959), 151.
2. Ibid., 236.
3. Charles Darwin, More Letters of Charles Darwin, ed. Francis Darwin, (New York: D. Appleton and Company, 1903), 252.
4. Dupree, Asa Gray, 266.
5. Asa Gray, "The Origin of Species" in Darwiniana (Cambridge, MA: The Belknap Press of Harvard University, 1963), 44.