The Development of the Philosophy of Species 301general causal underpinnings. A family resembles each other from the causes of
heredity acting according to Mendelian segregation and assortment through actual
causal relations, which point, ironically, Wittgenstein failed to appreciate (see below,
“Family Resemblance”). But just because we see a pattern does not make it a natural
class, either of a kind or a group. Hence the phenetic program failed, as it did not
restrict resemblance to causally linked objects (and thus it fell into the error of con-
fusing the recognition of patterns with the recognition of actual objects).The “New” Essentialisms
A “revival” of essentialism has occurred since the 1990s, associated with process
structuralism, which is basically a neo-Thomistic account of structure determin-
ing function,^49 causal essentialism, and a couple of philosophical attempts to revise
essentialism as developmental resources shared by members of taxonomic groups.
Origin Essentialism
The first new essentialism is Paul Griffiths’ “historical essentialism.”^50 Griffiths
accepts that variation within species is not a matter of what Sober^51 referred to as
deviation from a natural state, where the natural state, or “intrinsic nature,” plays
the role of essence. Instead, he sees the developmental system inherited by members
of a taxon as an extrinsic, or relational, essence: nothing that is not descended from
a common ancestor is a member of that taxon-kind. Griffiths accepts the cladistic
notion of monophyly as the only good license for projectability in induction, and
assigns that license to the shared developmental resources—the developmental sys-
tem and environmental and social resources of each organism—which are passed on
historically in a relatively, but not rigidly, invariant manner. This is not a “natural
state” essence so much as it is a phylogenetically entrenched essence. Some devel-
opmental states are more effective or deeply entrenched in the lineage than others,
and act as a brake on variation, licensing inferences that have a law-like nature,
albeit with exceptions. Historical, or origin (as the approach has come to be called)
essentialisms have also been proposed by Okasha^52 and Rieppel^53 and criticized by
Pedroso and Ereshefsky.^54
(^49) Goodwin et al. 1983 and Goodwin 1994 offer examples of the process structuralist approach. See the
discussion in Griffiths 1999.
(^50) Griffiths 1999.
(^51) Sober 1980.
(^52) Okasha 2002.
(^53) Rieppel 2010, see also Rieppel 2008.
(^54) Pedroso 2013, Ereshefsky 2014.