Full Idea
On all modern species concepts (except the phenetic), the property in virtue of which a particular organism belongs to one species rather than another is a relational rather than an intrinsic property of the organism.
Clarification
The 'phenetic' approach looks at physical features of the phenotype
Gist of Idea
Virtually all modern views of speciation rest on relational rather than intrinsic features
Source
Samir Okasha (Darwinian Metaphysics: Species and Essentialism [2002], p.201), quoted by Michael Devitt - Resurrecting Biological Essentialism 4
Book Reference
Devitt,Michael: 'Putting Metaphysics First' [OUP 2010], p.223
A Reaction
I am in sympathy with Devitt's attack on this view, for the same reason that I take relational explanations of almost anything (such as the mind) to be inadequate. We need to know the intrinsic features that enable the relations.