Saturday, February 26, 2011

A problem with arguments from poor design


As a public skeptic of the ability of Darwinian processes to account for complex cellular systems and a proponent of the hypothesis of intelligent design (1), I often encounter a rebuttal that can be paraphrased as "no designer would have done it that way." A classic example is the backwards wiring of the vertebrate eye (2). If no intelligent designer would have done it that way, the reasoning goes, then a blind, purposeless mechanism must be responsible, with natural selection being the prime candidate. This is a negative argument, reaching its conclusion in favor of the sufficiency of unintelligent processes by ruling out intelligence, which depends critically on our ability to differentiate useless from functional features. That ability has been severely called into question by the recent work of Hirotsune et al (3).

The modern molecular example of poor design is pseudogenes. Why litter a genome with useless, broken copies of functional genes? It looks just like the aftermath of a blind, wasteful process. No designer would have done it that way (2). Yet Hirotsune et al (3) show that at least one pseudogene has a function. If at least some pseudogenes have unsuspected functions, however, might not other biological features that strike us as odd also have functions we have not yet discovered? Might even the backwards wiring of the vertebrate eye serve some useful purpose?

The peril of negative arguments is that they may rest on our lack of knowledge, rather than on positive results. The contention that unintelligent processes can account for complex biological functions should, to the extent possible, be supported by positive results, rather than by intuitions of what no designer would do. Hirotsune et al's (3) work has forcefully shown that our intuitions about what is functionless in biology are not to be trusted.


Michael J. Behe

(1) Behe, M. J. Darwin's Black Box: The biochemical challenge to evolution. The Free Press, New York (1996).
(2) Miller, K. R. Life's Grand Design. Technology Review 97, 24-32 (1994).
(3) Hirotsune, S. et al. An expressed pseudogene regulates the messenger-RNA stability of its homologous coding gene. Nature 423, 91-96 (2003).



  1. The thing that has always struck me about the "argument from poor design" is that the people making the argument have so very little experience with design at all. As someone with 25 years of experience in software design, I can tell you that there are many times in which we say about each other's code "no intelligent entity would have coded it that way!" ;-)

  2. I. Byron, God could have made us invulnerable to bullets, fire, drowning, extreme cold/heat, spears, bacteria, viruses, fungi, parasites, broken bones, cancer (et cetera, etc.,etc.) and even to death.

    But that would prevent God's providential HIS-story from unfolding. God has purposed that in our universe there would be a 1. Pre-Fall world, a 2. post-Fall world and finally a 3. Redeemed world. It's in the redeemed world when (redeemed) humans will be impervious to all of the above.

    Possible evidence for macro-evolution doesn't disprove the existence of the Christian God. For all you know, theistic evolution or even progressive creationism is true. That is, God actually used evolution to bring about man. Though, I'm personally not convinced that this *is* the way God did it. This could possibly account for the tailbone.

    God isn't obligated to design "optimally". Also, unless and until you know the purposes of the designer you cannot know whether something is or isn't optimally designed. Sometimes aesthetic considerations trump optimality. For example, balloons on top of a car or a hood ornament aren't efficient aerodynamically. This answers both the testes and male nipple objections. Finally, there's anecdotal evidence that in extreme situations males can breastfeed infants.

    Finally, if men didn't have external testes or nipples there'd be less humor in the world. Heh

  3. Well put. The psuedogene argument in particular is somewhat of a "Darwin of the Gaps" appeal.

  4. In my comment above I wrote, "For all you know, theistic evolution or even progressive creationism is true. That is, God actually used evolution to bring about man.". I should have reversed "...theistic evolution or even progressive creationism" to " creationism or even theistic evolution.." since most Progressive Creationists reject macro-evolution yet the very next sentence implies that both affirm macro-evolution. If written the correct way, it wouldn't have implied that.

    Some versions of Progressive Creationism can account for why the fossil record may appear to support macro-evolution without macro-evolution actually being true.

  5. Byron, FYI the premier Old Earth Creationism ministry and website is the one by Hugh Ross at Reasons To Believe also has a page where one can access archives of their radio podcasts of Creation Update which ran from 2001 to 2009