Page 106 - MODES of EXPLANATION

Basic HTML Version

steps out to get a fresh cup of coffee. When she returns, the office door is closed and locked.
A handful of explanations are available. It may be that a serial killer has killed both Jane and
Robert and locked himself in the room. Alternatively, it may be that Robert stepped out to
use the bathroom and Jane left for home, locking the door behind her. Suppose Robert shows
up and reports that he was in the restroom. After he unlocks the door, Sally discovers that
Jane’s bicycle and bag are both gone. The best explanation appears to be that Robert went to
the bathroom and Jane left for home, locking the office door behind her. In virtue of this
theory offering the best explanation, it appears that we have good reason to think that the
theory is true
even though
Sally was unable to observe Jane’s departure.
Historical science relies heavily on inference to the best explanation:
“Historical scientists proceed
in roughly the following way: Observe and describe
puzzling t
ra
ces of long-past events. Postulate a common cause of tho
s
e traces. The
common cause is usually some token ev
e
nt or process that occurr
e
d long ago. Test
this hypoth
e
sis about the distant past against ri
v
al hypotheses
by searching for a
‘smoking gun
,’
or a pr
e
sent trace that, togeth
e
r with the othe
r
traces observed
s
o
far
,
i
s
better explained by one
o
f
the rival hypotheses than by the
o
ther.”
(Cleland, 2002
)
In order to consistently hold that historical science is not a source of evidence about the
world, one must further hold that inference to the best explanation is not a legitimate form of
inference.
The debate over the evidential status of inference to the best explanation is well worn
(Bex, 2012; Bex & Walton, 2010). While there is little agreement on the reliability of
inference to the best explanation, there is widespread agreement that the scientific realist is
committed to the view that inference to the best explanation is a legitimate form of inference.
The realist is committed to the view that the methods of science provide justification for our
beliefs about the world. Inference to the best explanation is an important method of theory
confirmation (Lipton, 2004; Henderson & Horgan, 2011). Thus, the realist is committed to
the view that inference to the best explanation is a guide to truth.
The upshot is that Ham’s rejection of neo-Darwinian evolutionary theory on the
grounds that it is historical science forces him to accept some version of scientific anti-
realism. There is no obvious lesson to take here with regard to the political issues with which
Kopplin is most concerned. Scientific anti-realism is a viable philosophical position. One’s
stance with regard to the realism/anti-realism debate has little to do with what one thinks
ought to be taught in high school classrooms.
There is, however, an important lesson to be learned about a particular attempt to
defend the creationist view. The classic strategy for defending creationism is to embrace a
“G-d of the gaps” style of argumentation. In short, the strategy is to show that there are
phenomena that a neo-Darwinian theory of evolution cannot explain but that creationism can.
If creationism offers the better explanation, we have good reason to accept the theory. Ham
5