 |
|
How Did We Get Here?
Letter 2
Phillip E. Johnson, November 19, 1996
Dear Kenneth
The Lennart Nilsson photographs that provide the occasion for
this discussion illustrate the development of the embryo in the
womb—NOT the historical process of how we get humans or
animals in the first place. These very distinct subjects are
often confused. For example, Darwinists long maintained that
"ontogeny recapitulates phylogeny," meaning that the human embryo
evolves through a fish stage and then through amphibian and
reptilian stages before it takes on its human form.
This recapitulation doctrine was discarded by science long ago,
but it survives in popularizations. For example, the Life
magazine article accompanying the Nilsson photographs admitted
that science has repudiated recapitulationism—but nonetheless
argued that features like supposed "gill slits" provide a "hazy"
version of evolutionary history. But human embryos never possess
gills, either in embryonic or developed form, and the embryonic
parts that suggest gills to the Darwinian imagination develop
into something entirely different.
The recapitulation thesis is false, and viewers of the Nilsson
photographs should be warned against any insinuations that the
photos illustrate a replay of evolutionary history. Agreed?
A related misunderstanding says that animals are much alike as
early embryos, and become dissimilar later in embryonic
development. Darwinian theory reasons that early embryonic
similarities reflect common ancestry, with evolutionary
differences emerging later in development. The Nilsson series
appears to support this theory with photos of vertebrate embryos
in mid-development that look similar in shape—but this
overlooks the crucial fact that the embryos develop to that stage
by very different means.
The early stages of vertebrate development are actually radically
dissimilar. If early developmental similarity is the test of
common ancestry, then vertebrates do not share a common ancestor.
So the Nilsson photos do not provide evidence of common ancestry,
and they certainly do not illustrate the Darwinian process of
mutation and selection. What these misunderstandings actually
illustrate is how overly enthusiastic Darwinists have sometimes
misled themselves. I note that you do not rely either on echoes
of recapitulationism or on early embryonic similarities to prove
common ancestry, and so perhaps you agree with me so far.
Now to the evidence you do cite. The mutation/selection
mechanism has never produced anything more impressive than
variations in pre-existing populations (microevolution). The
claim that natural selection can create new complex organs has
been challenged by the evidence of irreducible complexity at the
molecular level. (Should we discuss Darwin's Black Box, by
Michael Behe?) The fossil record also remains on the whole
pervasively anti-Darwinian, even though the paleontologists have
tried as hard as the embryologists to impose a Darwinian
interpretation. Where are the common ancestors of the animal
phyla? Where is the testable mechanism for macroevolution?
Did we evolve? Maybe, but very little is known about the
mechanism and much misinformation has been spread in an effort to
prove, in the words of your textbook, that "evolution is random
and undirected." How do you know that?
(go to next letter)
(go to previous letter)
(go to Debate contents)
Odyssey Home | How? | Morphing | Lens
Timing | Creepy Crawlies | Table of Contents
|
|
|