Geneticist Dan Graur of the University of Houston is implacably opposed to intelligent design — and brutally honest about his opposition, which makes for bracing clarity in what he writes. Recently he tweeted the following 12 principles of evolution, which he drafted.

You have to love Graur’s principles, because they capture orthodox neo-Darwinism in its purest form:

All of Evolutionary Biology in 12 Paragraphs, 237 Words, and 1,318 Characters

1. Evolutionary biology is ruled by handful of logical principles, each of which has repeatedly withstood rigorous empirical and observational testing.

2. The rules of evolutionary biology apply to all levels of resolution, be it DNA or morphology.

3. New methods merely allow more rapid collection or better analysis of data; they do not affect the evolutionary principles.

4. The only mandatory attribute of the evolutionary processes is a change in allele frequencies.

5. All novelty in evolution starts as a single mutation arising in a single individual at a single time point.

6. Mutations create equivalence more often than improvement, and functionlessness more often than functionality.

7. The fate of mutations that do not affect fitness is determined by random genetic drift; that of mutations that do affect fitness by the combination of selection and random genetic drift.

8. Evolution occurs at the population level; individuals do not evolve. An individual can only make an evolutionary contribution by producing offspring or dying childless.

9. The efficacy of selection depends on the effective population size, an historical construct that is different from the census population size, which is a snapshot of the present.

10. Evolution cannot create something out of nothing; there is no true novelty in evolution.

11. Evolution does not give rise to “intelligently designed” perfection. From an engineering point of view, most products of evolution work in a manner that is suboptimal.

12. Homo sapiens does not occupy a privileged position in the grand evolutionary scheme.

It’s fun to play around with these. Take principle 10 seriously, for instance, and taxonomically restricted genes (so-called “orphans”) represent a significant puzzle to neo-Darwinian evolution. The deepest question, of course, is this: Do these principles — in particular, numbers 4 through 12 — derive from observations, or are they imposed on observations?

Historical parallel:

And we recall that Galileo never made use of Kepler’s ellipsi, but remained to the end a true follower of Copernicus who had said “the mind shudders” at the supposition of noncircular, nonuniform celestial motion.

(Gerald Holton, Thematic Origins of Scientific Thought, Harvard University Press, p. 64)

Indeed, one could take this catechism to London in November, to the Royal Society meeting on alternatives to neo-Darwinism, as a template for where heresy may be expected to arise.

Image: Eastern imperial eagle, by AngMoKio [CC BY-SA 2.5], via Wikimedia Commons.