The Language of Argument

4 4 0

C H A P T E R 2 0 ■ S c i e n t i f i c R e a s o n i n g

LIVING wITH DARwIN^4

by Philip Kitcher

... Darwin’s own consideration of the concrete case argument focused on
some complex organs and structures that he rightly believed to be hard to
understand in terms of natural selection. Two examples are prominent in the
Origin, the eye and the electric organs found in some fish. The latter example
disconcerted Darwin because the fish with electric organs are of very differ-
ent types, and have their organs in different parts of their bodies. Much to
his relief, research on electric fish carried out by a contemporary who was
not sympathetic to evolutionary ideas—“McDonnell of Dublin (a first-rate
man)”*—revealed that, for each type of fish with an electric organ, there is a
related fish with a similar organ (not functionally electric) in the same posi-
tion. What had initially appeared to be the challenge of understanding how
different electric organs had been built from scratch, became the much sim-
pler question of how a similar change had occurred in each instance.
Darwin himself offered a tentative proposal about the evolution of the
eye. He supposed that sensitivity to light might come in degrees, and that
it might be possible to find, among existing organisms, some with a crude
ability to respond to light, others with a more refined capacity and so on
in something like a series. Perhaps, he speculated, research on these crea-
tures might expose reasons why the different levels of sensitivity provided

1. Explain what Behe means by “irreducible complexity.” Give examples of
   what is and of what is not irreducibly complex, according to Behe, then ex-
   plain why he takes the former to be and the latter not to be irreducibly com-
   plex. Why is irreducible complexity supposed to be a problem for Darwin’s
   theory of evolution?


2. Behe cites the human eye as evidence against Darwin’s theory of evolution
   (compare also Paley on p. 213). Explain Behe’s claims and arguments us-
   ing this example. How could Darwin best respond? Do you think Darwin’s
   theory of evolution can explain the eye? Why or why not?


3. Behe next cites cilia to argue against Darwin’s theory of evolution. Answer
   the same questions as in Discussion Question 2 about this example.


4. In addition to arguing against Darwin, Behe argues positively that “the con-
   clusion of intelligent design flows naturally from the data itself—not from
   sacred books or sectarian beliefs.” Explain Behe’s conclusion here and his
   argument for that conclusion. Do you agree with Behe? Why or why not?

Discussion Questions

* Francis Darwin, ed., Life and Letters of Charles Darwin, vol. 2 (London: John Murray, 1888), 352.

97364_ch20_ptg01_423-448.indd 440 15/11/13 12:09 3M

some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materiallyCopyright 201^3 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights,

affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.