Content Review of Dempster’s study of Patrick Matthew  

Hiram Caton

W. J. Dempster. Natural Selection and Patrick Matthew. Evolutionary Concepts in the Nineteenth Century. Edinburgh: Pentland Press. 1996

What selection means

This study rescues from obscurity the wealthy Scottish aboriculturist who in 1831 devised the concept of natural selection as the mechanism of species evolution. Not only is his concept very similar to Darwin’s (as Darwin acknowledged), but like Darwin, Matthew derived it from domestication experience. The key premise is the belief that the structural and phenotype variation achieved by domestication proves the mutability of species: there is no limit to the variation that may be induced in a variety, given time and effort. Dempster shows that this far-reaching theoretical position arose as an ‘obvious’ implication of the breeder’s experience. That breeding might achieve just about any result was part of the shop talk of breeders, expressing as it did a no-limits optimism. But then there was the other side of the story: time and effort. In practice, breeders dealt constantly with the persistence of the original type through the permutations and combinations of dominance, reversion, back-crosses, and hybridization. Marvellous things might be done with pigeons, but breeders didn’t really believe in the possibility of a flightless or four-legged pigeon. An acknowledged limiting condition, called correlation of parts, was that selection for any trait generates changes in other traits as well. Had this phenomenon been subjected to insightful empirical tests, it would have refuted the idea that domestic breeds are indefinitely variable. But breeders, as practical men, lacked the wherewithal to devise theoretically informed tests of heritability. This applies to the theoretically aware Matthew and Darwin. Darwin did indeed conduct many breeding experiments, but he lacked the theoretical sophistication to conceptualize them quantitatively. His results thus amounted to little more than anecdotal glosses on variation. Dempster highlights Darwin’s deficiency in this respect by passing in review his reaction to the experiments of Gabriel Naudin (1852). Naudin’s work highlighted particulate inheritance (later confirmed by Mendel), but Darwin’s strong bias in favor of ‘gradualism’ prevented him from recognizing the importance of Naudin’s work. It would have been relevant for Dempster to mention as well Alfred Wallace’s response to Mendel’s discoveries when they finally came to light: he dismissed them as of no relevance to evolution, and did so in Darwin’s name as well as his own. A very significant aspect of Dempster’s investigation (implicit in the foregoing remarks) is the vast gulf between breeding practice and the more formal knowledge of naturalists, botanists, zoologists, paleontologists, and the like. He illustrates the gulf in the case of Thomas Huxley and a few others. Their ignorance of breeding limited their ability to evaluate Darwin’s arguments for evolution, which depended heavily on evidence from domestication.

A prominent part of this study is Dempster’s rehabilitation of Lamarckian theory from Darwin’s snide remarks and deprecations, and the misrepresentation of his theory by a long string of theorists and historians. The excuse for this excursion is Dempster’s attention to Darwin’s heavy purchase on Lamarckism through his Pangenesis theory and in the extensively revised fifth and sixth editions of Origin. Wallace and Matthew, he points out, rejected Lamarckism without qualification, but many other evolution theorists incorporated it in one form or another. He points out that Darwin took Pangenesis from Buffon. He omits mention of Darwin’s correspondence with Herbert Spencer about the theory, relevant because Spencer also proposed a version of Pangenesis.

There are some errors. Cuvier’s theory of successive appearances of new taxa in the fossil record was interpreted by creationists as a warrant for claiming successive moments of divine creation through time, but, contra Dempster, Cuvier himself did not advocate this position. He held instead to an empiricist stance that in the absence of evidence no speculations should be advanced. Dempster also errors in ridiculing Lord Kelvin’s dating of the age of the Earth to 30 million years. This dating was independently confirmed by Heinrich von Helmholz and was accepted as warranted until the discovery of radioactivity added a hitherto unknown energy source. It is also incorrect to attribute an evolution theory to Mendel. He believed that his two laws refuted Darwin by showing that the variability required by his theory was contrary to fact. The author’s discussion of the state of evolution theory in the decades prior to the publication of the Origin is generally good, particularly in his recognition of the importance of the work of Edward Blyth. But he follows the crowd in dismissing the scientific value of Chambers’ Vestiges of the Natural History of Creation. This book went through numerous editions that were updated to take account of new evidence, and this was done with the collaboration of three established biologists. Dempster fails to acknowledge that Vestiges, and its companion volume Explanations, set out very trenchant arguments for a wholly naturalistic conception of natural phenomena and of human origins. Indeed, far more trenchant than anything Darwin wrote.

The Darwin fan club won't like this book. As Dempster notes with a whiff of Schadenfreude, the commissars of orthodoxy strongly discourage the faithful from reading the heretical sixth edition of Origin. I add my own cynical smirk by noting that the sixth edition is the one where Darwin changed the title from On the Origin of Species to the now standard Origin of Species.

To sum up: Dempster shows that domestication evidence is essential for understanding the selection concept used by Matthew and Darwin. He doesn’t quite say so, but his exposition suggests that the evidential value of Darwin’s long argument turns on the validity of his understanding of domestication.

It is a pity that the sales rank of this book is so low.

© 2008