‘Not to Be Used Again’:
Homologous Structures and the Presumption of Originality as a Critical Value
29 November 2006
One of the most common arguments used by evolutionists as a proof of naturalistic evolution points to the existence of homologous structures among different animal types. This argument also manifests as an argument against special creation and/or intelligent design. The following paragraph from a popular source online sums up the matter succinctly:
Homologous structures are body parts with similar arrangements derived from a common ancestor but used for different functions. The human arm, the horse’s forelimb, the whale’s flipper, and the dog’s front paw are all homologous structures which make use of the same basic bones and muscles. Why would an infinitely powerful designer choose to repeat the same design over and over in his creations? Why, in his infinite wisdom, could he not use a radically different design for each of his supposedly independent creations?1
It will not be our purpose here to discuss the scientific merits of the argument concerning homologous structures (see Related Articles, below). Rather, we will be defending and expanding upon a prior creationist defense made against this argument on strictly logical and philosophical grounds.
Elsewhere it has been capably pointed out that the argument from homologous structures commits a serious logical fallacy:
We can apply this analysis to a major evolutionary argument:1) If organisms X and Y have a common ancestor, they will have homologous structures;
2) X and Y have homologous structures;
3) X and Y have a common ancestor.
This demonstrates that it is an example of the fallacy of affirming the consequent. The conclusion is not proven—the homologous structures could be due to a common designer, leaving a ‘biotic message’ that there is a single designer of life rather than many.2
This argument may in fact be strengthened and reaffirmed through the understanding that the evolutionary argument from homologous structures hides an unsubstantiated presumption: That is, originality is a critical value which God would be compelled to follow. However, this presumption is the result of modern biases interpreting the biological evidence.
Rather, the suggestion of a ‘biotic message’ is quite accurate. Homologous structures, far from pointing away from a designer of infinite wisdom, would have indicated to readers of the Bible in their time a designer who did indeed possess infinite wisdom and mastery over His creation. It is only because modern persons have arbitrarily decided that a certain degree of what they see as ‘originality’ is a proper means value that the evolutionists’ argument carries any apparent force.
Something Old, Nothing New
To frame our argument against the evolutionists’ misuse of homologous structures requires us to have an understanding of certain values critical to ancient persons. Roman literature of the New Testament period tells us that ‘(t)he primary test of truth in religious matters was custom and tradition, the practices of the ancients.’3 In other words, old was good, and innovation was bad. Change or novelty was ‘a means value which serves to innovate or subvert core and secondary values.’4
Homologous structures would not have been seen as a case of a designer with no wisdom, or no designer at all, but something that brought honour to the Creator and would also indicate the Creator’s authority over and mastery of His creation.
By itself, this demolishes one part of the evolutionists’ argument and makes it, clearly, a case of arbitrary imposition of modern values. In a context such as the above, ‘radically different design’ would have indicated to an ancient reader either no deity, or else a deity whose means was chaos and instability, or a deity who did not have mastery over creation.
Because entirely new things were regarded with suspicion, it was more typical for ancient persons to borrow from and recast what was old and use it for their own purposes. An example of this is how John the Baptist set out to deliberately imitate the prophet Elijah by wearing similar clothes, or how Jesus chose 12 disciples to represent the 12 tribes of Israel, and stayed 40 days in the wilderness to purposefully parallel the Exodus. Similarly, today, a hunger striker may fast 14 hours, one for each of 14 prisoners being held against their will. Symbolic acts such as these, created to invoke a particular point, are part of normal human communication, but were especially important as an expression of cultural values in the biblical era.
A more directly germane example is given by Malina and Rohrbaugh in their Social Science Commentary on the Synoptic Gospels.5 They note specifically the example of Mary’s ‘Magnificat’ prayer as they explain:
To be able to quote the [Old Testament] tradition from memory, to apply it in creative or appropriate ways to the situation of daily living, not only brings honor to the speaker but lends authority to his words as well. The song of Zechariah, the so-called Benedictus, in Luke 1:68–79 is an example. It is stitched together from phrases of Psalms 41, 111, 132, 105, 106, and Micah 7. The ability to create such a mosaic implied extensive, detailed knowledge of the tradition and brought great honor to the speaker able to pull it off.
To express the application directly, in the eyes of an ancient reader, homologous structures would not have been seen as a case of a designer with no wisdom, or no designer at all, but something that brought honour to the Creator and would also indicate the Creator’s authority over and mastery of His creation.
We may conclude, in summary, that the evolutionist argument based on homologous structures is deeply flawed and highly subjective. Indeed, it is the sort of argument that comes of a ‘consumer culture’ in which one has more toys than one can possibly play with, yet always wants something more and something new. The lesson to be taken here is that God is not obliged to entertain evolutionists with more and newer designs simply because they think He should.
- Anon, ‘The Argument from Design?’. Return to text
- Jonathan D. Sarfati, Loving God with All Your Mind: Logic and Creation, Journal of Creation 12(2):142–151, 1998. Return to text
- Robert Wilken, The Christians as the Romans Saw Them, Yale University Press; 2nd edition, p. 62, 2003. Return to text
- John Pilch and Bruce Malina, Handbook of Biblical Social Values, Hendrickson; Revised ed., p. 19, 1998. Return to text
- Bruce Malina and Richard Rohrbaugh, Social-Science Commentary on the Synoptic Gospels, Augsburg Fortress; 2nd edition, pp. 293–4, 2003. Return to text