Whereas many people
readily accepted the idea of evolution, perhaps because the concept
had been discussed by biologists at least since 1809, when Lamarck
published his book Philosophic Zoologique, and in England
since 1844, when the book, Vestiges of the Natural History of
Creation, was published anonymously by Robert Chambers, many
remained sceptical about the mechanism proposed by Darwin. Already
after the first reading of the book, at the end of 1859, Darwin's
faithful "bulldog", T.H. Huxley, pointed out that the accumulation
of small variations constituted a serious problem, not the least
because the existence of inheritable variations with large effects
were known. In a review of the book he mentioned two instances of
this kind, hexadactyly in humans and short- leggedness in the
"ancon sheep". He even declared that he was not sure that Darwin's
method was correct.
This critique was
taken up by many quarters, and in 1872 Mivart published the book
The Genesis of Species which attempted to show that there
are many examples of changes of animals properties, which we may be
sure have occurred, and which could not possibly have originated
through the accumulation of small variations, because they
represented typical either-or situations.
Ellegard has studied
the English periodical press during the years 1859-1872 in order to
estimate the reception of Darwin's work. As it turned out, the idea
about evolution proper was readily accepted, but natural selection
was rejected almost ''unanimously. And he concludes that no doubt
Mivart's book had contributed essentially to this negative
attitude.
In fact, the
opposition continued during the rest of the century and the first
decades of the present one. It seems that the change of opinion was
the result of some mathematicians, and some biologists who were
clever mathematicians, suggesting that what had failed to
substantiate the mechanism of accumulation through selection, was
that Mendel's theory of paniculate inheritance, unknown to Darwin,
had not been incorporated. When this was done, they showed that it
was possible to account for evolution in mathematical
terms.
The reversion to the
belief in Darwinism, soon to be called "neo-Darwinism", was a very
fast event: most of the scientific world was converted in less than
two decades, which is a very short time for a new theory to become
established. It is difficult to understand the reason, for
everybody was aware of certain features that would be hard, or even
impossible, to achieve through the accumulation of small
variations. Only a very superficial acquaintance with ontogenetic
development and epigenetic mechanisms could apparently explain the
conversion.
But perhaps there
was a completely different reason too. namely that the founders of
neo-Darwinism claimed that the study of evolution had now become
mathematics and hence an "exact" science.
In fact, ever since
the thirties there were very few who dared to challenge the
new-born science, for instance d'Arcy Thompson, Willis,
Schindewolf, Goldschmidt and Severtsov. and they were treated more
or less with scorn.
The intention of
this section, besides outlining the history of the concept of
natural selection, was to show that during the greater part of the
history of Darwinism, the mechanism suggested by Darwin was not
accepted. Moreover, if it is accepted today that is not because the
mechanism as such has been demonstrated. To be sure the inheritance
of changes brought about by mutations has been shown to occur in
many cases, but successive accumulation has hardly been
demonstrated, and even then there is no evidence that it could
result in large modifications.
