Teaching about Scientific Dissent from Neo-Darwinism

In their recent Opinion article in TREE¹, Eugenie Scott and Glenn Branch argue that teaching students that there is a scientific controversy about the ‘validity of evolution’ is ‘scientifically inappropriate and pedagogically irresponsible’. In so doing, Branch and Scott assume that they have critiqued my position on the teaching of evolution. But they fail to define their terms and engage the main arguments for my position, misrepresenting it as a consequence. My position is not that students should be taught that there is a scientific controversy over the validity of evolution per se, but that they should be informed about the scientific controversies that exist about neo-darwinism, the long-dominant theory of evolution.

I recently co-authored a major law review article² arguing for this pedagogical proposal and have co-edited a peer-reviewed volume about the subject.³ The book develops a comprehensive pedagogical, legal and scientific case for exposing students to the scientific controversies that exist about the key claims of neo-darwinism, including the claim that the selection–mutation mechanism can fully account for the appearance of design in biological systems. Scott and Branch mention neither of these works, although my co-editor, the distinguished Darwin-scholar John Angus Campbell, asked Scott to contribute a critical response to the book, which she declined.

Instead of engaging the arguments of these works, Scott and Branch attempt to associate our position with that of holocaust deniers and creation scientists. They also repeatedly use the perjorative term ‘anti-evolutionist’, thereby confusing the issue⁴ and mischaracterizing the motives and rationale of those of us who want to see students informed of the scientific controversies that exist within and about aspects of contemporary darwinism.

Scott and Branch deny the existence of any significant scientific controversies about the ‘validity of evolution’. But the credibility of their position depends on definitional equivocation. All reputable scientists agree that ‘evolution happened’, they insist. Overwhelming evidence reinforces this opinion. And, of course, they are right if they equate ‘evolution’ with ‘change over time’ or ‘descent with modification’ (as they do when pressed).

Yes, life has changed over time. But, of course, neo- darwinism affirms a good deal more than that. In particular, it affirms that: (i) that an undirected processes, principally natural selection acting on random mutations, is sufficient to generate biological complexity; and (ii) all organisms have descended from a common ancestor.

Scott herself acknowledges significant scientific debate about the sufficiency of the neo-darwinian mechanism. Recently, in a public forum at the University of San Francisco, she also acknowledged that many evolutionary biologists now disagree about the truth of universal common descent. Our position, radical though it might seem, is that students should be informed about such dissenting opinion and, furthermore, that they should be told why some scientists doubt aspects of neo-darwinism.

Thus, Scott and Branch misrepresent our position when they suggest that we justify it mainly by an appeal to fairness. Teaching students about scientific controversies is less a matter of fairness (still less, to religious sensi- bilities as they imply) than it is a matter of full scientific disclosure. Students should know, for example, that many embryologists dispute that different classes of vertebrate embryos strongly resemble each other during their earliest stages of development⁵, although many American biology textbooks claim or show the opposite in their presentations of evolution (often using misleading photos or Haeckel’s famously inaccurate drawings). Students should also know that many scientists now question whether micro-evolutionary processes can be extrapolated to account for macroevolutionary innovation and that the lack of such a mechanism leaves unexplained the origin of major groups of animals, such as the Cambrian Metazoa⁶.

Scott and Branch acknowledge the existence of disputes about the sufficiency of the neo-darwinism mechanism, but dismiss them as being of little consequence to the status of contemporary evolutionary theory, as if the absence of an agreed mechanism of macroevolutionary change constituted a minor theoretical lacuna. Scott and Branch are forced by this logic, however, to defend a less than fully neo-darwinian view of evolution.

References

1. Scott, E.C. and Branch, G. (2003) Evolution: what’s wrong with ‘teaching the controversy’. Trends Ecol. Evol. 18, 499–502
2. DeWolf, D.K. et al. (2000) Teaching the origins controversy: science, religion or speech? Uni. Utah Law Rev. 39, 39–110
3. Campbell, J.A. and Meyer, S.C. eds (2003) Darwinism, Design and Public Education, Michigan State University Press
4. Meyer, S.C. and Keas, M.N. (2003) ‘The meanings of evolution’. In Darwinism, Design and Public Education (Campbell, J.A. and Meyer, S.C., eds), pp. 135–156, Michigan State University Press
5. Richardson, M.K. et al. (1997) There is no highly conserved embryonic state in the vertebrates: Implications for current theories of evolution and development. Anat. Dev. 196, 91–106
6. Valentine, J.W. (2003) On the Origin of Phyla, University of Chicago Press