Re: Evolution makes lots of testable predictions.

Loren Haarsma wrote:

"... Once an understanding of DNA was developed several decades later, a new
and independent way of testing evolutionary theory became possible...."

Such tests are fine for those who already accept the validity of evolutionary theory, but for those who don't, the tests at best only reveal how organisms are genetically related. Everyone recognizes that some organisms are more closely related than others, and antievolutionists/special creationists will be as pleased as anyone to see that the genetic codes of similar organisms are closer together than those of dissimilar ones (except for the chimp-human connection!). I believe that detailed genome constraints will not be anywhere near tight enough to be convincing to nonbelievers. Only if there were lots of complete DNA samples available from ancient, extinct organisms might it be possible to make a convincing case to someone who's not already a believer. That is, show how DNA developed, don't speculate about the historic significance of contemporary differences. But such endeavor isn't possible.

Far more compelling predictions can be made about relationships among fossils, as I pointed out previously. Special creationists have to think twice to explain those relationships (e.g., Flood geology won't cut it, nor will any scheme that claims every organism came into existence over a small time interval), whereas all they have to do to account for any DNA configuration is say, "That's the way God did it." That leaves the evolutionist in the position of having to say why God would not have done it that way--an impossible case to argue.

Don

  ----- Original Message -----
  From: Loren Haarsma<mailto:lhaarsma@calvin.edu>
  To: _American Sci Affil<mailto:asa@calvin.edu>
  Sent: Friday, December 17, 2004 2:20 PM
  Subject: Evolution makes lots of testable predictions.

    The question of whether or not evolutionary theory makes testable
  predictions has been raised a number of times -- most recently on this
  list in the last week or two.

    It seems to me that "historical science" theories (Big Bang cosmology,
  geology, biological evolution) can and do make lots of testable
  predictions of this general sort:

    Historical theory AAAAA says that system BBBBB was produced by a set of
  natural processes CCCCC. So if you perform experiment DDDDD on object
  EEEEE (a portion of system BBBBB), then based on inferences FFFFF, the
  results must fall in range GGGGG.
    If the results don't fall in range GGGGG, then -- assuming experiment
  DDDDD was performed properly and assuming inferences FFFFF are valid --
  then it's safe to say that object EEEEE was not formed exclusively by
  natural processes CCCCC. Other processes must have been involved.
    Often, this sort of testing can be used to distinguish between competing
  historical theories AAAAA1, AAAAA2, and AAAAA3.

    Big Bang cosmology and Inflation makes predictions about features of the
  cosmic microwave background and early galaxies, to name a few.
    Geology makes predictions about the structure and composition of tiny
  rocks and large geographical features.
    Evolutionary biology, in particular, makes predictions about genomes of
  species.

    Evolutionary theory -- that modern species were produced by natural
  processes of mutation and natural selection -- was developed before
  anything was known about DNA. It was developed based upon fossils records
  and geographical distributions of species and observation of mutation and
  natural selection at work today.
    Once an understanding of DNA was developed several decades later, a new
  and independent way of testing evolutionary theory became possible.
    Consider species BBBBB. Something of its evolutionary history can be
  hypothesized from its form, its geographical location, and fossils.
    Once something is known about the genomes of species related to BBBBB,
  evolutionary theory makes a prediction about the genome of species BBBBB.
  If evolutionary theory is true, BBBBB's number of chromosomes, the
  arrangement of genes on the chromosome, the sequences of those genes, and
  the sequences of non-coding introns and pseudogenes on the chromosomes,
  etc., all ought to fall within a certain range GGGGG. If you sequence its
  genome and find some results which fall well outside that range, then you
  should be able to conclude that some other processes (supernaturally
  miraculous, alien genetic manipulation, unknown natural mechanisms?) were
  partially responsible for species BBBBB. (As always, these conclusions
  depend upon certain inferences FFFFF. However, the more that is
  understood about how DNA works and how mutations can happen, the more
  tightly constrained and the more certain those inferences can be.)

    The number of species whose genomes are being sequenced is steadily
  growing, and will probably continue to grow for some decades. It seems to
  me that one of the things this will do is provide massive confirming (or
  disconfirming) evidence for evolution - since evolutionary theory really
  does make predictions about the possible ranges of those results.

  Loren Haarsma
Received on Sat Dec 18 04:31:06 2004