Page 105 - MODES of EXPLANATION

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less clear how one could repeat the tests of historical sciences. Must one rediscover the same
fossils?
While worries about the epistemic status of historical sciences are more widespread
than Kopplin suggests, it is unlikely that these concerns are congenial to creationism. Ham’s
distinction between historical and observational science is reminiscent of the empiricist
philosophy of science of the early 1900s. One of the many lessons we learned from
positivism is that it is notoriously difficult to distinguish between direct and indirect
observation. Ham’s attempted distinction between historical and observational science is
particularly vulnerable to Sorites objections. One might reasonably wonder what counts as a
phenomenon and an observation co-occurring. Information transfer is not instantaneous.
Surely the nanoseconds it takes for light to travel the distance from my computer screen to
my eye does not make my observation of my screen indirect. However, if the difference
between direct and indirect observation is temporal, one must somehow specify a minimal
interval between an event and an observation such that, if any longer interval of time passes,
the event was not directly observed. There are good reasons to be skeptical that any
principled distinction can be drawn between direct and indirect observation (whether
temporal or otherwise). Consequently, there are good reasons to be skeptical that one can
distinguish between historical science and observational science.
For the time being, however, set aside philosophical objections to Ham’s distinction
between observational and historical science. Further, for the sake of argument, grant Ham’s
claim that observational science, but not historical science, provides justification for our
beliefs about the natural world. One can only maintain that historical science is not a source
of evidence about the world if one is willing to hold that inference to the best explanation is
not a source of evidence.
Inference to the best explanation is frequently categorized alongside induction and
deduction as one of the three primary methods of inference. Suppose we have some set of
evidence, {E
1
, E
2
, …, E
n
}. Further suppose we have some set of theories, each offering to
explain this set of evidence, {T
1
, T
2
, …, T
n
}. Further suppose that some theory, T
m
, best
explains the evidence. Inference to the best explanation allows us to infer the (approximate)
truth of T
m
. In Devitt’s words:
“The basic argument for the unobservable entities is simple. By supposing they exist,
we can give good explanations of the behavior and characteristics of observed
entities, behavior and characteristics which would otherwise remain completely
inexplicable. Furthermore, such a supposition leads to predictions about observables
which are well-confirmed; the supposition is ‘observationally successful’. Abduction
thus takes us from hypotheses about the observed world to hypotheses about the
unobservable one.” (Devitt, 1991)
An example may help illustrate. Imagine that Sally and her two officemates, Jane and Robert,
are working late one night. Sally accidentally leaves her keys in the office when she briefly
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