Re: Alvin Plantinga's paper

Keith B Miller (
Wed, 20 Jan 1999 14:02:52 -0600

Moorad wrote:

>What does evolutionary theory predicts man to look like in the future? Will
>man remain bipedal? Will he evolve to become a flying animal? Evolutionary
>theory assumes man evolved from situation A to situation B and the
>predicative power is limited to finding evidence along that particular
>trajectory in time. It cannot predict anything beyond B or earlier than A.
>Therefore, the predicative power of evolutionary theory is to confirm its
>assumptions. Am I right?

Any good theory provides preditions of observations not yet made. If those
predicted observations are subsequently confirmed, then confidence in the
theory is increased. Historical sciences function in just this way.
Evolutionary theories, or geological theories, yield expectations of what
will be observed in specified situations (environments, localities, times.
strata, etc.). It matters not that the data to be observed pre-existed the
question being asked. As long as the scientist is blind to that data
before predicting its existence, the new observations serve to test the

Most research in other scientific disciplines involves the reconstruction
of past events. For example, a chemist may perform an experiment in which
two solutions are mixed. The chemist then analyses the product of the
reaction and infers, based on chemical theories, what actually took place
within the test tube. The process itself, the chemical event, was not
directly observed. Now, whether that analysis was done five minutes after
the reaction, or a million years after, does not change that fact that a
past event is being reconstructed from its products or effects.

Also, evolutionary theories can and are tested using living organisms and
communities. New insights have been gained from work with bacterial
cultures, in which evolutionary responses to selective pressures can be
observed in real time. Evolutionary theories generate testable
expectations about gene flow and selective pressures within biological
communities or species populations.


Keith B. Miller
Department of Geology
Kansas State University
Manhattan, KS 66506