Re: Alvin Plantinga's paper/Predictions

David Campbell (
Fri, 22 Jan 1999 10:53:35 -0400

>By difference in degree I mean something that can be gotten from something
>else in a continuous fashion. For instance, by breeding all sorts of dogs,
>we only get different looking dogs but dogs nonetheless. Difference in kind
>require some sort of discontinuous transition. Of course, on the molecular
>level, there is no true continuous change since all changes are of a finite
>nature--e.g., exchanging some strands in a DNA.

If common descent is true, then all organisms have been gotten from others
in a continuous fashion. I think you have something else in mind, but am
not sure just what your criteria are.

>Weather study, or the model for the solar system, is based on mathematical
>models that give rise to chaotic behavior and in that sense we cannot make
>long range predications--but can make excellent short term predictions. I
>do not think such models exist in evolutionary theory even to make short
>range predictions. For instance, given a particular DNA, and whatever else
>you need to determine the organism involved, can you tell me what will be
>the outcome if I tinker with the DNA in a particular fashion? For instance,
>is the resulting organism even viable?

There is some evidence for chaotic aspects of evolution, although it is not
yet proven.
If the function of the DNA you tinker with is known, then predictions may
be possible. However, we're still not able to predict the structure of a
protein from the complete amino acid sequence. If the relevant chemistry
is sufficiently well-known, the outcome may be fully predictable. For
example, it is known exactly what mutation is required to cause sickle-cell
anemia. Likewise, it is known that a lot of mutations will not have any
effect. There have also been some successful attempts at causing bacteria
to develop a particular mutation. If I remember correctly, the most
successful approach has been to determine what parts of the enzyme are most
important to its function and induce mutations there.

David C.