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Philosophy of
Classification
John Dupré
ISKO, London 2012
The Problem
Classification is a basic prerequisite for language,
for knowledge of the exterior world, etc.
What makes two things members of the same kind?
Are kinds discovered (“natural”) or invented?
Possible Solutions
1. Realism about kinds (natural,
discovered): essentialism
2. Nominalism: kinds are created
by us through language
3. Non-essentialist realism;
pluralism
Transcendental
Essentialism: Plato
Immanent Essentialism:
Aristotle
Sceptical Nominalism:
John Locke
Real and nominal essences: we
are not equipped to perceive real
essences, so kinds are created by
us on the basis of the way things
appear and the uses we put
things to.
Real essences are unattainable
and very likely useless.
Empirical Nominalism:
Charles Darwin
The theory of
evolution by
natural selection
suggests that in
nature there are
differences
everywhere but
no sharp
distinctions
between kinds.
Natural Kinds
Microbes and the Tree of
Life
Nominalism to (Realistic)
Pluralism
Cedar-wood: >13 different species, 10
genera, 5 families: all or almost all
provide wood valued for rot or insect
resistance.
Cedrus, a genus of Alpine/Himalayan
trees, some of which produce cedarwood.
Cedrus
Cedar
Slimy Salamanders
Frost and Hillis, Herpetologica, 1990
Plethodon albagula
Different scientists support
classification in terms of phlyogeny,
reproductive isolation, ecological
role, phenotypic traits and more;
no reason to assume that one view
is correct or that different views will
draw the same distinctions
Conclusions
1. Classifications are discovered,
and chosen; nature offers many
ways to classify, we choose
which to use.
2. Choices of classificatory scheme
are relative to our purposes.
The support of the Economic and Social
Research Council (ESRC) is gratefully
acknowledged. The work presented
forms part of the programme of the
ESRC Genomics Network at Egenis.