Tuesday, January 5, 2010

Transitional Forms

Not infrequently I come across the question, “What about the evidence for transitional forms? Hasn’t science proved that transitional forms exist, thereby validating Darwinian evolution?”

I understand why people might believe this to be the case. The claim that science has found transitional intermediates in the fossil record is taught in schools and universities throughout the land, and is made frequently and loudly by scientists and by the media, seemingly with the authority of evidence behind them.

But this claim has no basis in evidence, but instead is made solely because it is a fundamental and necessary prediction of Darwinian evolution.

To understand the issue, let’s take a big-picture, historical look at it. The real conflict is between two explanations for the diversity of life on Earth. The Darwinian view (or its modern synthesis, generally known as neo-Darwinism) is one. The other—the one held by all the biologists, anatomists, physiologists, and paleontologists of Darwin’s day, and the one Darwin intended to replace—I’ll call typology. Typology sought to explain—and did a very good job of explaining—the two most important characteristics of living things, which are their similarities and their differences. Biologists long knew that all life shared certain similarities, and that different groups of living things shared even more similarities with one another than with species outside their group. The typological explanation for the similarities among living things was (and is) that all things were created—and designed to fulfill their role—by the same Creator.*

But groups of living things exhibit stark differences as well. Indeed, the life forms (extant and extinct) identified by Darwin’s time fell rather neatly into groupings—“types”—that were separated, in many cases by rather large gaps. Thus, mammals all share characteristics that set them apart from birds or reptiles, and bats all share characteristics that set them apart from rodents. Typology said (and says) that gaps exist because the hypothetical things in-between (the half-reptile, half bird or the half-rodent, half bat) are nonsensical and non-functional.

Darwin, on the other hand, postulated that those gaps have been populated throughout life’s history by other living things—transitional intermediates. And on his view, there would have to have been not just one or two such forms bridging the apparent gaps, but that
the number of intermediate and transitional links, between all living and extinct species, must have been inconceivably great.
He knew that no such transitional forms were known at that time, but then paleontology was a relatively young discipline in Darwin’s day. He wrote that the fossil record was
the most obvious and gravest objection which can be urged against my theory [and the reason] all the most eminent paleontologists… and all our greatest geologists… have unanimously, often vehemently, maintained the immutability of species.
So a prediction central to the verification of his theory was that further fossil digging would uncover a great many of these “inconceivably great” number of transitional forms.

For the ensuing 150 years, the history of paleontology has been primarily a search to find these forms predicted by Darwin, the evidence that would validate his theory. What has been the result? Scientists have uncovered hundreds of millions of new fossil forms. Unfortunately (for Darwin’s theory), they have invariably fallen into one of two categories—they have either fit into a type already known to science, or they have represented yet a new type, one not transitional to known types, but rather requiring yet another exceedingly vast number of transitional forms to link that type to other known ones.

Contrary to the educational and media misrepresentation, here’s the true situation as described by arguably the preeminent paleontologist of our generation. Harvard’s late Stephen Jay Gould called
the extreme rarity of transitional forms in the fossil record… the trade secret of paleontology.
His colleague, Niles Eldredge, concurred:
We paleontologists have said that the history of life supports [the story of gradual adaptive change], all the while really knowing that it does not.
Stephen Stanley, commenting on research from Wyoming’s Bighorn Basin—where a continuous record of deposits covering millions of years led paleontologists to expect evidence for transitional forms—wrote that
the fossil record does not convincingly document a single transition from one species to another.
So the central evidentially-based prediction made by Darwin has roundly failed. That it continues to be claimed today that science has documented transitional forms has nothing to do with evidence and everything to do with the centrality of these forms to the theory. It’s really nothing more than a group wish-fulfillment exercise on the part of those who want Darwinism to be true.

* I’ll discuss in one of the next posts why typology still does a better job than neo-Darwinism of explaining the similarities among living things.


Jordan said...

I may show my extreme ignorance of biology/paleontology here but a question I would have is how would we really know if a fossil is transitional or not?

Is the prediction that there should be numerous transitional fossils a part of the modern neo-Darwinian synthesis?

Rick Gerhardt said...

Hi Jordan:

The answer to your second question is yes. The modern synthesis simply added the understanding of genetics to the Darwinian paradigm; its proponents still argue for the existence of transitional intermediates (hence the disingenuous teaching of Archaeopteryx as a transitional form and the publishing--as by National Geographic as recently as 2001--of fraudulent examples).

With your first question, you've put your finger on a sore subject. Because transitional forms were so central a prediction of Darwin (and because the fossil record doesn't bear that prediction out), many 'believers' have relaxed the definition to make it easier to point to examples. On that view, any new fossil that is intermediate in any way--either chronologically or characteristically--between any other two living things can be touted as proof of Darwinism.

But what Darwin had in mind was truly transitional, having characteristics some of which were not yet fully functional or fully adapted, but on their way to becoming more useful. (I may touch on this when I blog about similarities among living things).

This aspect was, and remains, problematic, and so modern Darwinists ignore or downplay it.

BTW, the modern synthesis is a dying paradigm, and many are the calls--even by biologists committed to naturalism and (therefore) evolution of some kind--for a 'third synthesis, since the modern synthesis (neo-Darwinism) has by now so clearly failed to account for the evidence.

Thanks for reading.

Mike Caba said...

Game, set, match.