Evolution - Is evolution science
I recently fisked a Richard Dawkin’s contribution to the Times Online. One of Richard Dawkin’s comments however merits further investigation.
The relevant chapter of my Climbing Mount Improbable is called “The fortyfold Path to Enlightenment” in honour of the fact that, far from being difficult to evolve, the eye has evolved at least 40 times independently around the animal kingdom.
The evolution of the eye has been a history of ad hoc explanations (Explanations given after the fact without any other justification for the express purpose of explaining that fact). Dawkin’s here reiterates a common theme of the eye having evolved convergently (i.e. Independently in different organisms) 30 to 40 times. This claim of convergent is based on the differences in the eyes and the lack of a common ancestor that could be interpreted to have had the required primitive eye for the cases in question. It is an Ad Hoc claim in that the only evidence that it is true is
A good example of this claim of convergence is between the human eye and the octopus eye. Genome Research has this figure which shows the normal phylogeny and basis for requiring that the eye evolution of humans and octopi be convergent. The full paper however has even more interesting comments.
This view has been changed, however, by Gehring and Ikeo (1999), who maintain that the expression of the common master regulator Pax6 in both types of eyes indicates the divergence of these two types of eyes from a single prototype eye present in the common ancestor of cephalopods and vertebrates. It has previously been reported that Pax6, a "master control" gene for the development of the eye, is highly conserved across species. Within molluscs, it has been shown that the scallop, ear shell, and squid all express Pax6 (Tomarev et al. 1997)
There are two things to note here. Firstly, the Pax6 Gene is highly conserved across many species. This makes convergent evolution of the gene pretty much a statistical impossibility as this very specific gene would have had to have evolved nearly identically in separate species. Whilst evolutionists can cope with things looking similar on the outside, the incredible similarity in the actual DNA code for a supposed instance of convergent evolution makes this claim absurd.
The second thing to note is that the claim of convergence itself was an Ad Hoc explanation, created specifically to deal with observed features that did not fit predictions of a continuum of features (the phylogenic tree) amongst related species. So even though convergence was Ad Hoc, and now research on the Pax6 Gene has shown that this ad hoc convergent explanation cannot be true, evolution is protected by yet another Ad Hoc explanation by pushing the creation of this gene back to a common ancestor of both, in this case, the octopi and homo sapiens.
As the paper states
In spite of the evolutionary divergence between octopuses and humans, 69.3% of the genes examined (729 of the 1052 genes) were commonly expressed in the camera eyes of human and octopus. Moreover, comparison of octopus-eye ESTs with genes in the human connective tissue indicates that the similarity of gene expression between human and octopus eyes should be remarkable.
Essentially, despite the large divergence according to evolutionary theory, there is a remarkable amount of homologous (very similar) sequences. Evolution would have predicted that no significantly homologous genetic sequences should have been found between the octopus eye and the human eye. Yet this prediction has proven to be false. However, by the addition of another Ad Hoc explanation, evolution is not questioned and still explains the facts at hand.
Karl Popper’s criteria of Falsification was created specifically to refute Ad Hoc explanations being added on in order to save a theory or hypothesis.
The Marxist account of history too, Popper held, is not scientific, although it differs in certain crucial respects from psychoanalysis. For Marxism, Popper believed, had been initially scientific, in that Marx had postulated a theory which was genuinely predictive. However, when these predictions were not in fact borne out, the theory was saved from falsification by the addition of ad hoc hypotheses which made it compatible with the facts. By this means, Popper asserted, a theory which was initially genuinely scientific degenerated into pseudo-scientific dogma.
These factors combined to make Popper take falsifiability as his criterion for demarcating science from non-science: if a theory is incompatible with possible empirical observations it is scientific; conversely, a theory which is compatible with all such observations, either because, as in the case of Marxism, it has been modified solely to accommodate such observations, or because, as in the case of psychoanalytic theories, it is consistent with all possible observations, is unscientific.
Comparing evolutionary theory's treatment of octopus and human eyes and these comments it seems clear that Evolution is surviving merely on a series of Ad Hoc explanations and so is not science.