Archive for the ‘paleontology’ category

The failure of Intelligent Design

February 18, 2011

“Were there no example in the world of contrivance except that of the eye, it would be alone sufficient to support the conclusion which we draw from it, as to the necessity of an intelligent Creator.  It could never be gotten rid of; because it could not be accounted for by any other, supposition, which did not contradict all the principles we possess of knowledge.[i]

–William Paley, Natural Theology, 1857

“To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree.  Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple…can be shown to exist…then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real.[ii]

– Charles Darwin, On the Origin of Species, 1859

“By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution.”[iii] 

–Michael Behe, 1996.

Charles Darwin refuted the teleological argument from design in 1859.  Apparently Behe didn’t get the memo.  Through his theory of evolution by means of Natural Selection, Darwin accomplished what earlier evolutionists could not.  Unlike previous theorists such as Lamarck and Erasmus Darwin, Darwin (and Alfred Russel Wallace working with him) provided a working mechanism for evolution. In short, Darwin’s theory of Natural Selection replaced Paley’s divine watchmaker with a blind watchmaker; the selective force of nature.  Following the strengthening of Darwinian theory by intellectuals on both sides of the Atlantic Ocean, especially after the development of the Modern Synthesis in evolutionary biology, evolutionary theory effectively replaced “Design” as a creative force.

Natural Selection, therefore, is able to explain organs and features of organisms formerly relegated to creation by an “intelligent Designer”, or a “divine watchmaker” of sorts.  Regardless of whether it is Paley’s eye or Behe’s bacterial flagellum, evolutionary theory effectively explains the development of these organs and features.  Therefore, the “Watchmaker hypothesis,” in both its historical and modern forms, does not present an effective challenge to the efficacy of evolutionary theory.  Thus, the argument from “Design”, or “irreducible complexity”, is not an adequate tool with which to challenge evolutionary theory.  Both fail to undermine the strength of evolutionary theory on closer inspection.  Although one might ask “what good is 2/10ths of an eye?”, any working “eye” is better than no eye at all.  Even if we are referring to just a few light-sensitive cells that are useful for an organism to detect light or predators, these cells will provide a definite survival advantage compared to organisms that lack these cells. In time, variation and selection can and do build more complex organs through differential survival rates.  In the case of “irreducibly complex” organs, the key flaw in Behe’s argument is the fact that he fails to account for the fact that so-called “irreducibly complex” organs can and do have other uses if a component or group of components are removed from them.  Natural selection works by jury-rigging and adaptation of available features, not by the design of new ones.  Therefore, the “watchmaker hypothesis” fails on all counts.

Another key aspect of modern arguments from design is the “fine-tuning” argument for the existence of the universe. This argument, stated simply, alleges that since the universe appears to be “finely tuned” for the existence of life as we know it (i.e. cosmological constants are exactly what they need to be for life to exist as we know it), that the universe therefore must be designed.  While this argument seems cogent at first glance, it is, in fact, fatally flawed.   In fact, the apparent “fine tuning” of the universe is exactly what one would expect if life evolved.  Natural selection produces organisms that are well-fit to their environment.  If life did, in fact, evolve, it did so in this universe, on this planet, governed by the constraints placed upon it by the existing cosmological constants.  You do not build a vehicle that sinks quickly but has really good wheels if you are only going to be using it in an ocean.  Rather, you construct a vehicle that is well-adapted for oceanic travel.  Natural selection works the same way.  It is governed by physics and chemistry as well as biology and ecology.  Natural selection, in short, is as much a slave to cosmological constraints as organisms are to their dietary requirements.  Thus, the cosmological argument is as much a failure as the “watchmaker hypothesis”.

Another key argument advanced by Intelligent Design proponents can be described in the following manner. The proteins/molecules/cells, etc. that make up life are extremely complex.  It is extremely improbable that they developed through solely naturalistic means. Therefore, these features must be designed.  However, this approach is philosophically and scientifically flawed.  Scientists have done a decent job exploring the origin of life. Even though scientists have not definitively explained the origin of life, they have developed some tantalizing glimpses at possible explanations for this event. This topic is relatively complex, and a bit intensive for a short post, so if you’re interested I’ll refer you to the work of Robert Hazen as a first guide to this topic. See, for example, his book “Genesis“. I will focus on the philosophical flaw with this argument in this post.

The philosophical argument inherent to this portion of the Intelligent Design argument can be re-phrased in the following manner.  A million (pick your favorite large number here, and replace “A million” with it if you’d like) lottery tickets are sold for a lottery. One ticket must win.  Each ticket represents a possible combination of proteins (the building blocks of DNA).  The “winning ticket” is the actual combination generated by nature.  According to the Intelligent Design approach, since a million tickets (possible protein sequences/amino acids) exist, the chances of drawing the winning ticket are extremely low, and therefore no ticket will win.  However, we know this to be false; one ticket ultimately DOES win.  Therefore, as improbable as the development of DNA sequences was, by nature, it was at least possible.  And, in fact, there are possible ways to increase the probability of the development of complex protein sequences (Hazen discusses the possibility of proteins growing within the microstructures of carbonate rocks, a hypothesis which explains the extremely high proportion of “left-handed” amino acids). Therefore, the Intelligent Design perspective once again proves flawed.

Before closing this essay, I will mention a few other key claims/approaches fronted by Intelligent Design proponents. The first is Dembski’s Explanatory Filter, which fails miserably as a tool to supposedly discern design in nature (see critique here). The second is the claim that natural selection cannot “increase information” in a genome.  Here’s a rebuttal for that claim as well.  Finally, perhaps the most ridiculous claim advanced by Intelligent Design advocates such as Stephen Meyer is the claim that the “Cambrian Explosion” somehow undermines evolution.  This is the old “there are GAPS!!!  Gaps in the fossil record!” argument trotted back out to play. Even a cursory glance at modern paleontology proves such a claim irreparably flawed.  A good explanation of why such an argument is flawed can be found in one of my all time favorite books on transitional forms, Donald Prothero’s “Evolution: What the fossils say and why it matters“.  For a good online critique of the “Cambrian Explosion” argument advanced by Design advocates, see Keith Miller’s article (part one here and part two).

Therefore, as demonstrated, upon closer inspection, the arguments against evolution advanced by Intelligent Design proponents consistently fail to withstand scrutiny.  I consciously avoided arguments from social ills in this post (“well evolution influenced Hitler, or communism, or what have you”) due to the extremely flawed nature of this type of argument.  What is more important is attacking so-called “science” of Intelligent Design.  As I’ve shown here, even a cursory critical glance at the pseudoscientific structure of Intelligent Design reveals massive and irreparable flaws. Therefore, Intelligent Design fails as a science.

Works Cited:
Behe, M.  Darwin’s Black Box: The Biochemical Challenge to evolution. Free Press, New York. 1996.

Darwin, CR. The Origin of Species.  Harvard University Press, Cambridge.  First Ed. facsimile, 2002 (1859)

Paley, W. Natural Theology: or, Evidences of the Existence and Attributes of the Deity, Collected From the Appearances of Nature. Gould and Lincoln, Boston, 1857

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Megaloceros and orthogenesis

September 24, 2010

Megaloceros on display at AMNH

Megaloceros, commonly (and wrongly) known as the “Irish Elk” offers a good example of an organism utilized as proof of orthogenesis during the latter half of the 19th century and the early 20th century.  During this period, paleontologists utilized the term “orthogenesis” to explain trends in the fossil record.  Under the model of orthogenesis, once a species begins to develop, it continues to develop along that line and exhibits an inability to stop this process of development.  In the case of Megaloceros, the argument was structured such that through the process of orthogenesis, Megaloceros’ antlers grew to extreme sizes.  Ultimately, this unchecked antler growth caused the extinction of Megaloceros.  This example offers a good model to demonstrate why orthogenesis does not work.  A trait isn’t going to survive if it causes a problem for the survival of the organism in question.  Ultimately, even if selective pressures do support the development of larger antlers in Megaloceros, the antlers won’t get large enough to cause extinction.  If an individual Megaloceros has antlers so large that they end up getting caught in trees (part of the orthogenesis argument), then it’s not going to have much success with reproduction. Sure, a few individuals with extremely large antlers might get to reproduce, but as a rule, most of these will, in fact, be weaned from the gene pool.  This is why orthogenesis does not work.

If you’re interested in this topic, check out Stephen Jay Gould’s article “The misnamed, mistreated, and misunderstood Irish Elk.” The article is available in his 1977 book Ever Since Darwin.

Ontogeny trumps Phylogeny

September 24, 2010

A recent paper published by Museum of the Rockies paleontologists John Scannella and Jack Horner, “synonymy through phylogeny, illustrates that Torosaurus, a genus originally described by OC Marsh, is in fact an adult form of Triceratops.  For a basic article on the topic, click here.  The citation information for the original Scannella and Horner article is as follows, and is available here if you have access to the Journal of Vertebrate Paleontology:

Scannella, J., & Horner, J. (2010). Torosaurus Marsh, 1891, is Triceratops Marsh, 1889 (Ceratopsidae: Chasmosaurinae): synonymy through ontogeny, Journal of Vertebrate Paleontology, 30 (4), 1157-1168.

Publications such as this one highlight the difficulty with which paleontologists define species.  It’s generally impossible to go back and look at skin (with a few key exceptions, such as the hadrosaur “mummy” at the AMNH), behavior, or other non-skeletal traits.  Thus, paleontologists are stuck trying to define species and genera from bones  alone, more often than not.  However, this article highlights the self-correcting nature of science.  While any historian of science can highlight numerous social influences on science, when at its best, science  in fact can be a self-correcting enterprise.  OC Marsh described Torosaurus and Triceratops as two separate genera.  Scannella and Horner come along a century later, with more specimens to compare, and correct Marsh’s mis-classification.  This is self-correcting science at its best.