Charles Darwin's On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life, chapter ten, “On the Imperfection of the Geological Record:”
“Those who believe that the geological record is in any degree perfect, will undoubtedly at once reject the theory.”
That seems clear. It is followed immediately by the following argument:
“For my part, following out Lyell's metaphor, I look at the geological record as a history of the world imperfectly kept, and written in a changing dialect; of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved; and of each page, only here and there a few lines. Each word of the slowly-changing language, more or less different in the successive chapters, may represent the forms of life, which are entombed in our consecutive formations, and which falsely appear to have been abruptly introduced. On this view, the difficulties above discussed are greatly diminished, or even disappear.”
I put more weight on the one clear sentence, than on all the poetry that follows.
“Those who believe that the geological record is in any degree perfect, will undoubtedly at once reject the theory.”
That seems clear.
It is indeed. Darwin is saying that if the fossil record is actually a perfect, complete record of every living thing which have ever lived on the face of the Earth, then the apparent "gaps" would show that evolutionary change had not taken place, because a gap in the record would mean an actual discontinuity in the life history.
HOWEVER, Darwin goes on to explain (CORRECTLY) that the fossil record is actually composed of only very isolated "snapshots" of certain places, times, and content. He's absolutely correct on this point.
It's very, very rare for the body of *any* animal, especially land animals, to be preserved at *all*. In most environments, the body will be eaten, decomposed, eroded, pulverized, or destroyed in any of countless different ways long before it could be "stored away" for later generations of paleontologists to find. And if it *does* manage to get buried in good condition through some enormous stroke of luck when the environmental conditions are just right, there's the question of whether it will *stay* in good shape over the next several million years, or be destroyed by worms, burrowing insects, bacteria, acidic groundwater, subsequent erosion, etc. etc. The extremely rare survivors of *that* can be subsequently buried so deep by other deposition that we'll never find them unless we dig up every square foot of the Earth to a depth of thousands of feet, or can be destroyed by subduction, or lost under a sea or ocean (there aren't many fossil hunters wandering around on the ocean floor), etc. etc. etc.
So Darwin correctly pointed out that the fossil record *itself* is such a spotty one that "gaps" in the fossil record are *expected*, and can not themselves be taken as evidence of the non-existence of certain forms or species.
The truth of this will become obvious when you realize that there are no fossilized examples of the vast majority of LIVING species. We *know* that these species exist (3,000,000+ and counting), and yet *most* of them have left no fossil trace of their existence. And so it obviously must have been for the countless species which have come and gone in the past, over hundreds of millions of years. Only a rare few have left a trace of their passing, which we have managed to find.
It is followed immediately by the following argument: “For my part, following out Lyell's metaphor, I look at the geological record as a history of the world imperfectly kept, and written in a changing dialect; of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved; and of each page, only here and there a few lines. Each word of the slowly-changing language, more or less different in the successive chapters, may represent the forms of life, which are entombed in our consecutive formations, and which falsely appear to have been abruptly introduced. On this view, the difficulties above discussed are greatly diminished, or even disappear.”
I put more weight on the one clear sentence, than on all the poetry that follows.
And well you should, because he's absolutely correct.
Think of it this way -- if you tried to trace your family tree, anything beyond a few hundred years ago would be *extremely* spotty. Entire wings of your family which once lived and thrived would have left no modern trace of their existence -- no lasting record that they had ever lived. Even your direct lineage (your great-great-great-grandfather, his father, his parents before him, etc.) would have major holes in it as you tried to reconstruct your descent from, say, your original Celtic ancestors. Does this mean that you didn't actually *have* a great-great-great-grandfather? Or does it just mean that it's very rare for people hundreds of years ago to have their lives documented in detail, *and* for those records to survive the long passage of time, *and* for the few surviving records to end up in locations where you can manage to locate them when you're trying to find them (as opposed to lost in someone's attic trunk five thousand miles away, listed in no index or catalog)?
Gaps in the fossil record tell us little, because the fossil record *itself* has left vast numbers of living things "undocumented". Instead, we should be thankful for the fossils which *have* miraculously survived the eons and then fallen into human hands, and learn what we can from the evidence we *do* manage to glean from the past.
See for example Taxonomy, Transitional Forms, and the Fossil Record. Excerpt:
The recognition and interpretation of patterns in the fossil record require an awareness of the limitations of that record. Only a very small fraction of the species that have lived during past geologic history is preserved in the rock record. Most marine species are soft-bodied, or have thin organic cuticles, and are essentially unpreservable except under the most extraordinary conditions. Furthermore, the destructive processes active in most marine environments prevent the preservation of even shelled organisms under normal conditions. Preservational opportunities are even more limited in the terrestrial environment. Most fossil vertebrate species are represented by no more than a few fragmentary remains. Because of the preservational biases of the fossil record, paleontologists must reconstruct evolutionary relationships from isolated branches of an originally very bushy tree.Also see: The Fossil Record: Evolution or "Scientific Creation"[Note: "preservational bias" means that some kinds of organisms, and some kinds of environments/sediments, are more suitable for the preservation of fossils than others. - Ich.]
[...]
There are two opposite errors which need to be countered about the fossil record: (1) that it is so incomplete as to be of no value in interpreting patterns and trends in the history of life, and (2) that it is so good that we should expect a relatively complete record of the details of evolutionary transitions within most lineages.
What then is the nature of the fossil record? It can be confidently stated that only a very small fraction of the species that once lived on Earth has been preserved in the rock record and subsequently discovered and described by science. Our knowledge of the history of life can be put into perspective by a comparison with our knowledge of living organisms. About 1.5 million living species have been described by biologists, while paleontologists have catalogued only about 250,000 fossil species representing over 540 million years of Earth history (Erwin, 1993)! Why such a poor record?
[...]
From this brief survey of fossil vertebrates, it is clear that transitional forms between higher taxa are common features of the fossil record. The morphology of species within a higher taxonomic group becomes less divergent toward the point of origin of that group. Morphological diversity and disparity increase with time. In addition, transitional species possess mixtures of morphologic characters from different higher taxa often to the extent that their taxonomic assignment is uncertain. This pattern is obscured by taxonomy which gives a false impression of discontinuity. The fossil record thus provides good evidence for the large-scale patterns and trends in evolutionary history. Recognizing its limitations, the fossil record appears to be consistent with the wide range of evolutionary mechanisms already proposed.
For more transitional fossils (and documentation of creationist lies about it), see for example:
Index to Creationist Claims: Claim CC200: There are no transitional fossils.Here are some of my prior essays on this same topic:Taxonomy, Transitional Forms, and the Fossil Record
On Creation Science and "Transitional Fossils"
The Fossil Record: Evolution or "Scientific Creation"
No transitional fossils? Here's a challenge...
Paleontology: The Fossil Record of Life
What Is A Transitional Fossil?
More Evidence for Transitional Fossils
The Origin of Whales and the Power of Independent Evidence
PALAEOS: The Trace of Life on Earth
Transitional Fossil Species And Modes of Speciation
Evolution and the Fossil Record
Smooth Change in the Fossil Record
Transitional fossil sequence from dinosaur to bird
And:Now, getting back to specifics, the point you keep missing -- even though I over-belabored the point and drove it into the ground in my last post to you -- is that regardless of the "gaps", there is a vast amount of "nongap" data that you seem very determined to totally ignore. That available data itself makes an overwhelming case for Darwinian evolution. Why do you keep failing to address any of it? Why do you keep fixating on the inevitable "gaps", and not on the evidence? The evidence is *far* more complete than the "gappers" like to imply, and makes an incredibly compelling case on its own. Why aren't you looking at *that*?
Now back to your specific charge. You write of, "the many rationales Darwin's defenders provide to explain away the gaps in the record". First, no one is trying to "explain away" the gaps. What we're trying to explain to the creationists who "can't see the forest for the gaps" is that:
1. There will always be gaps in the fossil record, for the obvious fact that not everything gets fossilized, then not everything that gets fossilized will survive (many are destroyed by erosion, subduction, etc.), then not every fossil that survives will be accessible (some will be buried deep in the Earth), then not every accessible fossil will be discovered (people can't scour every square inch of the planet), etc. etc. Hell, there aren't even fossils for each and every species that exists *today*, so obviously the fossil record will always be a small fractional slice of all life that has ever lived on the Earth.
2. Because there will always be gaps, one can't conclude a damned thing from the simple fact that gaps exist in the record. Of *course* they do. There would be gaps no matter *what* the reality of the history of life on Earth was, even if it *was* truly gradualistic change. Even then there would still be gaps in the fossil record, because that record *itself* is "gappy" -- fossilization occurs too rarely to cause a "snapshot" of every significant lifeform at every significant moment in time at every significant location on Earth. Period.
3. So the meaningful question (for anyone who actually *wants* to seek the truth, instead of seeking excuses to ignore the evidence like the creationists do) is this: Is the pattern of the fossil evidence we *do* manage to find (including the pattern of the "gaps" in that evidence) of the type we would expect to find if (a) Darwinian evolution actually happened in the way predicted by the Theory, and (b) fossilization produced imperfect snapshots of that process in the way fossilation is known to take place (and not take place)? The answer to *that* question is a resounding "yes".
Come on, DRF, if you've done real engineering, you *know* how to do these kinds of analyses. If you have a process that occurs in a certain way, *and* you can only take samples or observations of that process at certain intervals or from certain narrow viewing angles or whatever, you know how to work out how to test whether the results of your limited sampling method matches the expected operational results or not. It's not rocket science.
Similarly, it's not hard to determine whether the fossils that we *do* find (GIVEN THE KNOWN LIMITATIONS OF FOSSILIZATION AND RECOVERY) are of the number, kind, and pattern that we would expect to find if life arose by evolutionary processes. And when we do such determinations, we find that the actual fossil record *does* match the predictions of evolutionary biology. So any whining about "there are still gaps" is just tunnel-visioned naysaying.
These are not "rationales". These are informed analyses. And it's not just "Darwin's defenders". Anyone with any existing belief can perform the same analyses and get the same results -- if they honestly want to. The creationists don't.
On the same subject Darwin himself wrote:There's absolutely nothing in the fossil record that "undermines" Darwinian evolution. The *only* thing I've seen the creationists even *attempt* to offer in support of such a ludicrous statement is itself an obvious, blatant fallacy -- all such claims rest on the fallacy that "absence of evidence is evidence of absence". In other words, they rashly conclude that if there's a gap in the fossil record, it represents "proof" that there are no transitions to be found. The obvious nature of the fallacy is twofold:
1. Many of the gaps are simply spans where no fossils are available AT ALL, for ANY animals of any kind, because of subduction, deep deposition, or other obvious reasons. It really is obviously a "missing data" problem, *not* a "missing XYZ when everything else has been found" problem, as the creationists like to dishonestly imply. For example, it's extremely rare to find *any* mammal fossils of any kind from the Oligocene era. It's not just the "transitions" which are missing from that era, almost *all* fossils from that era are unobtainable.
2. You'd think the creationists would stop making this error, because they've fallen on their faces *so* many times already doing it. It seems that just when the creationists like to make a Poster Child of a particular "missing link", paleontologists find it after all. Whales with legs, proto-birds with partially formed wings, fish with feet, proto-mammals with jaw joints that are half reptilian and half mammalian... The list goes on and on. Creationists kept ridiculing biologists for not finding these "obviously" ludicrous life forms which would "obviously" remain "missing links" forever as an eternal "gap" in the fossil record -- and then such fossils *were* found to fill in the gaps that the creationists had wrongly presumed were "real" gaps. Oops.
Furthermore, by ranting obsessively about "gaps", you keep overlooking the fact that many, many, *MANY* lineages HAVE been filled by enough fortuitously found fossils to provide a clear, continuous record of evolutionary change across many millions of years, of the kind that the creationists keep falsely claiming aren't possible and don't actually happen. Oops again for the creationists. Any special reason you're not discussing *those*?
Additionally, you're glossing over the fact (I *hope* it's because of ignorance, not dishonesty) that even when "gaps" exist, they're often small and minor enough that the fossil sequences which have been found provide an overwhelmingly complete picture of the evolutionary relationships. Creationists often like to try to convince people that any gap at all is a vast discontinuity, but let's face it, when the gaps are minor enough and the nongap data is voluminous enough, it doesn't take a genius to literally "connect the dots" when the picture is that complete and obvious.
Finally, the creationists like to "forget" to deal with the fact that even when (often relatively minor) gaps exist in fossil sequences, DNA analysis and other kinds of independent evidence can and does provide overwhelming cross-confirmation of the fact that the apparent fossil lineages (gaps and all) are, indeed, true lines of descent. But the creationists don't like to talk about that...
We shall, perhaps, best perceive the improbability of our being enabled to connect species by numerous, fine, intermediate, fossil links, by asking ourselves whether, for instance, geologists at some future period will be able to prove, that our different breeds of cattle, sheep, horses, and dogs have descended from a single stock or from several aboriginal stocks [...] are really varieties or are, as it is called, specifically distinct. This could be effected only by the future geologist discovering in a fossil state numerous intermediate gradations; and such success seems to me improbable in the highest degree.Here Darwin was pointing out that new breeds can appear in just dozens or hundreds of years, and yet representative fossils of the transitions are unlikely to be produced or preserved, because they are so few in number (and fossilization is a rare event requiring special circumstances).
Even so, Darwin's pessimism was overstated. Countless transitional fossils, including many gradual sequences, have been found, wonderfully supporting evolution in both large and small scopes. But Darwin's points still stand and explain why we'll likely never be able to recover *all* (or even a large majority) of such sequences.