32 Michael Ruse
there a switch of world views — perhaps even a switch of worlds — that required
more of a leap of faith than an appeal to reason? Or was the change smoother,
as more conventional philosophies of science might lead one to expect. Was the
change more (say) in a Popperian vein, where basically the facts told against the
older position and people shifted because this was the reasonable thing to do? The
prize goes to both disjuncts! At a broad level, there are certainly Kuhnian aspects
to the revolution. Most strikingly, there were people who simply could not see the
other side’s point of view — clever people, that is, who knew the ins and outs of
the issues. Most prominent of these was Louis Agassiz [E. C. Agassiz, 1889]. He
had staked out an idealistic position before theOrigin[Agassiz, 1859] — one that
came directly from hisNaturphilosophenteachers (Friedrich Schelling and Lorenz
Oken) when he was a student in Munich — and try as he might, he could never
accept evolution.
Something like this makes perfect sense on the Kuhnian scenario and fits uncom-
fortably into a philosophy of science that makes rational choice the sole criterion
of theory change. However, in other respects the Darwinian Revolution seems very
non-Kuhnian. People may not have been able to see the viewpoints of others, but
it is hard to say that this was a function of different facts, a key element in Kuhn’s
theory of change. Fact-change is simply not true of the Darwinian Revolution.
Everything about Darwin himself denies this claim. We have seen this again and
again. Darwin was like Plato’s Demiurge, shaping what he already had. This
applied to ideas as well as facts. Everyone knew about Malthus, for instance, but
it was Darwin’s genius to put the ideas into a theory of change rather than a the-
ory that argued that change is impossible. Likewise, the facts of the successes of
animal and plant breeders were well known. It was again Darwin’s genius to make
something of these facts. The same is true of so much else — the vaguely progres-
sive fossil record, for instance, and the peculiarities of biogeography. Particularly
important for Darwin were earlier discoveries in embryology. Darwin seized on
the similarities of embryos and made this a key support for the arguments of the
Origin.
So, we have to say that the Darwinian Revolution does not fit readily into simple
theories of theory change. Probably in part this was because it was not simply
a scientific revolution, but one that included religious beliefs and thoughts about
the status of humans and (particularly for people like Huxley, including many
today) hopes for the kind of secular, progressivist society that one thinks is the
ideal for humankind today. I return to the metaphor of a kaleidoscope. It was not
so much that there was a change of facts, but that the facts were shaken up and
pushed into making a whole new picture — a picture that some welcomed, some
disliked, but towards which few were indifferent. And that thought is no bad way
to end this discussion of Charles Darwin and the revolution with which his name
is associated.