One of the pieces included in Bully for Brontosaurus, a collection of essays by evolutionary biologist Stephen Jay Gould, is entitled "From a Jumbled Drawer." In this piece, Gould provides an example of the value of critical thinking in contrasting the views of two distinguished figures of the late nineteenth century: the naturalist Nathaniel Shaler and his friend William James, the philosopher and psychologist.
Shaler, Gould explains, had developed as a scholar under the powerful influence of biologist Louis Agassiz at Harvard University. And although Agassiz opened the first Museum of Comparative Zoology at the same time that Darwin's Origin of Species was published, he was a devout creationist. In fact, his entire career was based on the premise that "species are ideas in God's mind, made incarnate by His hand in a world of material objects."
Shaler was only following in the creationist footsteps of his master when, in one of his earliest articles, he misclassified brachiopods as mollusks due to what he perceived as a shared bilateral symmetry. Such symmetry, as a feature of animal taxonomy, he described as a "study of personified thought"—or, as it might be called by current anti-Darwinists, a feature of "intelligent design."
Implicit in this strain of anti-evolutionary thought was a belief that "human races are separate species, properly and necessarily kept apart both on public conveyances and in bedrooms." In keeping with the racism of patrician Boston, he also believed in Condorcet's notion of "using biology as an accomplice" in advocating a nativist social policy, which severely restricted immigration of non-white Americans.
Ultimately, Shaler's belief in the steady progress of the human race as the embodiment of a divine order was rooted in a simple, but false, claim about probability. He claimed that "The possibility of man's development has rested on the successive institution of species in linked order . . . if any one of the species had failed to give birth to its successor, the chance of the development of man would have been lost." But, as Gould points out, if one accepts the chance and contingency that are central to Darwin's theory, the appearance of the human race would then have have been impossible.
In fact, Shaler's faulty logic was noted by his friend William James at the time. Although James was also a devotee of Agassiz, he was far more critical of the anti-scientific tenor of his creationism. As James rightly concluded, the actual result of evolution is the only sample we have. He reasons thusly:
We never know what end may have been kept from realization, for the dead tell no tales. The surviving witness would in any case . . . draw the conclusion that the universe was planned to make him and the like of him succeed, for it actually did so. But your argument that it is millions to one that it didn't do so by chance doesn't apply. It would apply if the witness had preexisted in an independent form and framed his scheme, and then the world had realized it.
Gould wisely summarizes this debate as follows: "Old, bad arguments never die (they don't fade away either), particularly when they match our hopes."