Evolution's Credibility Problem (part 1)

(Part 1 in a 3 part series)

"The extreme rarity of transitional forms in the fossil record persists as the trade secret of paleontology — we fancy ourselves as the only true students of life’s history, yet to preserve our favoured account of evolution by natural selection we view our data as so bad that we never see the very process we profess to study."
Gould, Stephen J., "Evolution's erratic pace", Natural History, vol. 86, May, 1977

"No wonder paleontologists shied away from evolution for so long. It never seemed to happen. Assiduous collecting up cliff faces yields zigzags, minor oscillations, and the very occasional slight accumulation of change--over millions of years, at a rate too slow to account for all the prodigious change that has occurred in evolutionary history. When we do see the introduction of evolutionary novelty, it usually shows up with a bang, and often with no firm evidence that the fossils did not evolve elsewhere! Evolution cannot forever be going on somewhere else. Yet that's how the fossil record has struck many a forlorn paleontologist looking to learn something about evolution."
Eldredge, Niles, Reinventing Darwin, 1995

"To this day, excuses for the incompleteness of the fossil record, as in the fable of the emperor's clothes, overshadow the inescapable: The expression of novelty in nature arises suddenly."
Schwartz, Jeffrey H., "Adaption and Evolution." (Book Review). History & Philosophy of the Life Sciences, 2001, Vol. 23 Issue 3/4

"Given the fact of evolution, one would expect the fossils to document a gradual steady change from ancestral forms to the descendants. But this is not what the paleontologist finds. Instead, he or she finds gaps in just about every phyletic series."
Mayr, Ernst, What Evolution Is, 2001

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Critics of evolutionary theory often point to the inadequacy of the fossil record to support Darwin's claim that life has been one slow progression from a common ancestor to the diverse species we witness today. The above quotes by supporters of evolution, along with many others that could be employed, make it abundantly clear that this criticism is no idle claim. For whatever reason, the fossil record continues to offer a paucity of support for the Darwinian notion of gradual change over time. While it might theoretically still be true, this is not the place to which one must look for a primary defense of the idea.

Apparent transitional fossils — the Holy Grail of evolution — are few and far between, and the geological strata is characterized by sudden appearance of new forms followed by long periods of limited diversity within those forms (i.e., stasis). This leads one to wonder if the transitionals are elusive by nature (as Gould argued) or if they are scarce because there were no such transitions.

If one were committed to the evolutionary hypothesis, and were guided by the fossil evidence alone, then it would seem reasonable to consider the possibility that biological change did not progress in a small stepwise fashion, but instead made great leaps forward ("saltations") at key points in the history of earth. This is the "hopeful monster" scenario advanced by Berkeley geneticist Richard Goldschmidt, which received only ridicule from his peers.

Why, though, should the consideration be so foreign to evolutionary theorists that life has bridged the great functional gaps between species all in single great leaps? Isn't the evidence pointing here, and aren't scientists concerned to follow the evidence wherever it leads? Isn't saltationism even a conceptual possibility? What is the principled objection to such an idea that keeps the theory trained primarily on the gradualistic model?

I submit that it is a matter of credulity.

To accept that the numerous and unique attributes that make up a newly appeared species, genus, family, etc. can come together at once to produce such a novelty is simply beyond the ability for even the most optimistic evolutionist to believe. For example, the bat appears suddenly in the fossil record, essentially in its modern form, complete with echolocation capability, yet no one would presume to suggest that the accompanying bone length and density adjustments, skin arrangement, cardiovascular alterations, and echolocation system all came together in one freak confluence of fortuitous mutations. That is too absurd even to imagine.

Additionally, the theory that the first organism to appear on earth was a single celled creature, like bacteria, has fallen out of favor in modern times. It is now assumed that there must have been some cascading series of "proto-cells" leading up to our ultimate cellular ancestor. And why is this assumed, in spite of the lack of geological or experimental evidence to support the idea? Because now that we have come to grasp the astonishing complexity of the cell it is simply too incredible to believe that it has appeared all at once.

The ironic thing is that critics of evolutionary theory have actually been accused of a "failure of imagination." In explanation of living organisms or their biochemical systems, which are too complex and interdependent to have come about in a stepwise fashion, evolutionists often appeal to imaginative scenarios. Rather than producing fossil intermediates and reproducible chemical pathways, which might settle the question, they offer just-so stories instead. However, an abstract theoretical framework is no substitute for empirical verification, and cannot be considered more than a hypothesis until such verification is forthcoming.

But if incredulity is a valid reproach to an idea, then why can we not also apply it to the supposed smaller steps of the gradualistic theory? Is the theory automatically plausible simply because it is alleged to occur in smaller increments? Are critics so irrational if they fail to be convinced by the evolutionary story even in this form? As it turns out, Intelligent Design (ID) theorists make the point that 1) the "small" steps are not all that trivial and 2) that small steps just won't get you where you need to go in most cases.