RANDOM DRIFT: CHANCE AND EXPLANATION IN EVOLUTIONARY BIOLOGY
Embargo until
Date
2006-08-03T15:28:39Z
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Johns Hopkins University
Abstract
The central claim for which I argue in this dissertation is that there are
important phenomena that occur by random drift that evolutionary biologists explain
using a strategy I term “process explanation.” This claim puts me at odds with
an influential view about the nature of explanation that I term “Hempelianism.”
Hempelianism is the view that the scientific explanation of a particular event E
requires (a) showing that E was to be expected, or indicating the degree to which
it would have been rational to expect E’s occurrence; and (b) laws of nature. My
central claim entails that both (a) and (b) are false. A process explanation consists
of a narrative describing events causally relevant to the event to be explained. These
narratives need not contain laws, show that the event to explained ought to have been
expected, or indicate the degree to which it would have been rational to expect the
event. My position about random drift also puts me at odds with evolutionists who,
influenced by Hempelianism, claim that only natural selection can explain evolution.
In my argument, I articulate the strategy of process explanation and defend it against
Hempelian critics; describe a mechanism of random drift known as “indiscriminate
ii
sampling;” and describe process explanations of phenomena of drift that occur by
indiscriminate sampling.