Repository logo
 

Sources of evolutionary contingency: chance variation and genetic drift

Accepted version
Peer-reviewed

Type

Article

Change log

Abstract

jats:titleAbstract</jats:title>jats:pContingency-theorists have gestured to a series of phenomena such as random mutations or rare Armageddon-like events as that which accounts for evolutionary contingency. These phenomena constitute a class, which may be aptly called the ‘sources of contingency’. In this paper, I offer a probabilistic conception of what it is to be a source of contingency and then examine two major candidates: chance variation and genetic drift, both of which have historically been taken to be ‘chancy’ in a number of different senses. However,jats:italiccontra</jats:italic>the gesturing of contingency-theorists, chance variation and genetic drift are not always strong sources of contingency, as they can be non-chancy (and hence, directional) in at least one sense that opposes evolutionary contingency. The probabilistic conception offered herein allows for sources of contingency to appropriately vary in strength. To this end, I import Shannon’sjats:italicinformation entropy</jats:italic>as a statistical measure for systematically assessing the strength of a source of contingency, which is part and parcel of identifying sources of contingency. In brief, the higher the entropy, the greater the strength. This is also empirically significant because molecular, mutational, and replicative studies often contain sufficient frequency or probability data to allow for entropies to be calculated. In this way, contingency-theorists can evaluate the strength of a source of contingency in real-world cases. Moreover, the probabilistic conception also makes conceptual room for the converse of sources of contingency: ‘sources of directionality’, which ought to be recognised, as they can interact with genuine sources of contingency in undermining evolutionary contingency.</jats:p>

Description

Keywords

Evolutionary contingency, Sources of contingency, Sources of directionality, Chance variation, Random mutations, Genetic drift, Information entropy

Journal Title

Biology and Philosophy

Conference Name

Journal ISSN

0169-3867
1572-8404

Volume Title

35

Publisher

Springer Science and Business Media LLC

Rights

All rights reserved