This document discusses the concept of essentialism in biology and its history. It argues that the idea that pre-Darwinian biologists held an essentialist view that prohibited biological change is incorrect. While the term "essentialism" has been used in various ways, essentialism per se was not prevalent in biology and did not constrain early evolutionary thought. The document traces how the idea of an "Essentialism Story" arose in the mid-20th century and became cemented in scientific thought despite a lack of evidence. It examines different forms of essentialism and argues that some modern formulations are not inherently at odds with evolutionary biology.

1. And in the essential vesture of creation
Does tire the ingener.
[Othello II, 1]
The philosophical origins of
biological essentialism
—John Wilkins—

2. • That natural kinds must have unique necessary
properties
• This is a modal essentialism (there are other kinds, as
we shall see)
• Employed in various disciplines
• Biology (especially WRT genes, species and
taxonomy)
• Psychology (Gelman, etc., on childhood cognitive
dispositions)
• Medicine, Physics, Mineralogy, Geology, Soil
science, etc ...
Scientific essentialism

3. Biological (taxic)
essentialism
• The view that
• Pre-evolutionary and anti-evolutionary
scientists
• … hold to an essentialistic metaphysics that
prohibited change between kinds
• and that kinds have necessary properties
(e.g., genetic, behavioural or morphological)
• This view is sometimes still asserted (e.g.,
Alexander Bird): “the first X was born of a pre-
X”

4. • From the late 1950s, Plato and, later, Aristotle
were accused of bequeathing essentialist
metaphysics to biology
• Part of the tradition of seeking the metaphysical
foundations of science begun in the 1930s
(e.g., E.A. Burtt)
• Metaphysical determinism of scientific theories
is now widely accepted
Aristotelian essentialism

5. Essentialism Story
• Gave rise to the Essentialism Story of Ernst
Mayr, David Hull and Elliot Sober
• Before Darwin, biologists (naturalists) were
constrained by essentialist thinking
• Every member of a kind was held to have
essential characters
• Change between kinds must therefore either
not occur or be saltative (i.e., non-Darwinian)

6. Darwinian nominalism
• Acc. to the Essentialism Story, Darwin adopted
a nominalism about kinds
• Every member of a kind (e.g., a species) was
a unique particular
• No species had unique necessary properties
true of all members
• Population thinking (Mayr)
• Species are individuals (particulars) –
Ghiselin, Hull

7. • In fact, no evidence of essentialism of taxa in
biology is to be found
• Essence plays little or no role even as early as the
17th century (e.g., Grew)
• Essence of parts, organisms simply meant the
typical form (Grew through to Goethe)
• Alarm first sounded by Paul Farber in the 1970s
and Scott Atran in the 1980s
• Ron Amundsen and Polly Windsor have attacked
it more recently, along with Richard Richards and
I
• Objections to Darwin were always, from the start,
about teleology and selection, not essentialism
[Sachs]
The nonexistence of
essentialism

8. In 1910, Dewey, just after the semicentenary
celebration of the Origin, wrote of the Greeks’ core idea
of form:
“This formal activity which operates throughout a
series of changes and holds them to a single
course; which subordinates their aimless flux to
its own perfect manifestation; which, leaping the
boundaries of space and time, keeps individuals
distant in space and remote in time to a uniform
type of structure and function: this principle
seemed to give insight into the very nature of
reality itself. To it Aristotle gave the name, εῖδος.
This term the scholastics translated as species.
…
Why did the Essentialism
Story arise?

9. “The conception of εῖδος, species, a fixed form
and final cause, was the central principle of
knowledge as well as of nature. Upon it rested
the logic of science. Change as change is mere
flux and lapse; it insults intelligence. Genuinely to
know is to grasp a permanent end that realizes
itself through changes, holding them thereby with
in the metes and bounds of fixed truth.
Dewey: Influence of Darwin

10. The rise of the Essentialism
Story
• The centenary of the Origin was of course 1959
• Writers had to find ways to mark out Darwin’s originality
• In 1957, Ernst Mayr referred to “typological thinking” and
sheeted it to Aristotle:
“ Typological thinking finds it easy to reconcile the
observed variability of the individuals of a species with
the dogma of the constancy of species because the
variability does not affect the essence of the eidos [the
Greek term translated as “species”] which is absolute and
constant. Since the eidos is an abstraction derived from
human sense impressions, and a product of the human
mind, according to this school, its members feel justified
in regarding a species “a figment of the imagination,” an
idea.
• Arthur J. Cain, a student of Mayr’s, repeated and elaborated
the claim the next year

11. • In 1963, a graduate student at the University of Indiana’s
HPS program did a seminar with Popper
• Popper took David Hull’s essay and sent it to BJPS: “The
effect of essentialism on taxonomy: Two thousand years
of stasis”
• This cemented the Essentialism Story in popular,
philosophical and scientific thought (around 400 citations I
can find so far)
• In 1968, Mayr took the term “typological” and equated it with
Popper’s and Hull’s use of “essentialist”
• So “type” = “essence” = “antievolution”
• Typology was creationist (Mayr called some typologists
creationists even though they were evolutionary
biologists!)
The hardening of the
Essentialism Story

12. Popper
“I use the name methodological essentialism to
characterise the view, held by Plato and many of
his followers, that it is the task of pure knowledge
or science to discover and to describe the true
nature of things, i.e. their hidden reality or
essence.
[The Open Society and its Enemies, 1945]
He contrasts it to
“methodological nominalism [which] aims at
describing how a thing behaves, and especially,
whether there are any regularities in its
behaviour.

13. Quine in “Two Dogmas” and
“Three Grades”
“ The Aristotelian notion of essence was the forerunner, no doubt,
of the modern notion of intension or meaning. For Aristotle it
was essential in men to be rational, accidental to be two-legged.
… Things had essences, for Aristotle, but only linguistic forms
have meanings. Meaning is what essence becomes when it is
divorced from the object of reference and wedded to the word.
[”Two Dogmas of Empiricism” 1951)
“ Aristotelian essentialism … is the doctrine that some of the
attributes of a thing (quite independently of the language in
which the thing is referred to, if at all) may be essential to the
thing and others accidental. E.g., a man, or talking animal, or
featherless biped (for they are all the same things), is essentially
rational and accidentally two-legged and talkative, not merely
qua man but qua itself. {”Three Grades of Modal Involvement”
1953]

14. The rise of “essentialism”
Educational Popper Quine

15. The rise of “Aristotelian
essentialism”
Quine Hull

16. All variants
Similar patterns emerge in German and French
Darwin
Sachs

17. Science by Definition
• Hull is basing his story on Popper and Scriven
(an essay in 1959 entitled “The Logic of
Criteria”)
• Attack on Analytic Definition:
• The assumption that we can define terms in
an essentialistic or analytic fashion, and
thereby know something
• Science-By-Definition (SBD)
• Aristotle did not practice SBD in his natural
history, but observation and experiment
• When he uses SBD, it is always in a
categorical or logical context (so far as I
know)

18. Linnaeus’ Essentialism
• Character essentialis,
or essential
characters, were
diagnostic, not
constitutive and
hence only
inadvertently
definitional
• Linnaeus knew they
were simply about
recognition
Salices: or, An essay towards a general history of sallows,
willows & osiers, their uses and best methods of
propagating and cultivating them by Walter Wade, Dublin
1811

19. “ If the essential characters of all genera had been
discovered, the recognition of plants would turn out to be
very easy, and many would undervalue the natural
characters, to their own loss. But they must understand
that, without regard for the natural character, no one will
turn out to be a sound botanist; for when new genera are
discovered, the botanist will always be in doubt if [he]
neglects the natural character. Anyone who thinks that he
understands botany from the essential character and
disregards the natural one is therefore deceiving and
deceived; for the essential character cannot fail to be
deceptive in quite a number of cases. The natural
character is the foundation of the genera of plants, and no
one has ever made a proper judgement about a genus
without its help; and so it is and always will be the
absolute foundation of the understanding of plants.
[Philosophia botanica 1751]

20. Whewell and
the Method of Type
Taxonomic definitions identified a type taxon (usu. a
species), around which classifications were arranged
The “type species” of a genus was the “most typical” form of
it
“These lessons are of the highest value with regard to all
employments [sic] of the human mind; for the mode in
which words in common use acquire their meaning,
approaches far more nearly to the Method of Type than to
the method of definition. (Whewell 1840, vol 2, pp. 517–
519)
“So long as a plant, in its most essential parts, is more like
a rose than anything else, it is a rose. (p.520)

21. Kinds of essentialism
“ Essence, (essentia, from esse, to be,) “the very being of
anything, whereby it is what it is.” Locke. It is an ancient
scholastic word, which cannot be really defined, and should
be banished from use. (Jevons 1870, p.335)
• “Essence” has a number of disparate meanings
• Psychological [folk]
• Human [historical and social]
• Logical [semantic, linguistic]
• Metaphysical [Aristotelian essentialism, universalism,
Platonism]
• Physical [natural kind]
• Biological [taxic]
• And others...

22. Psychological [folk]
• Imputing to
objects an
internal persistent
nature on the
basis of
superficial
appearances
“Psychological essentialism in children”, Gelman 2004

23. Human [historical and
social]
• Imputing to sociocultural
groups a shared
persistent set of
properties of each
member of the group.
Examples, gender (Heyes
2000), nations (White
1965), ethnicities (Gil-
White 2001), races
(Sesardic 2010) and
medicine (Jensen 1984;
Pickering in press).

24. Logical [semantic, linguistic]
• Imputing to terms an
invariant and unique
meaning. Examples:
The
Aristotelian/scholastic
tradition, Cicero.
Criticized influentially
by Popper (Open
Society, Vol 1: Plato,
chapter 3), Quine

25. Metaphysical [Aristotelian
essentialism, universalism,
Platonism]
• The claim that there
are universals that
are facts about the
world (Aaron 1952;
Quine 1951,
1953b).

26. Physical [natural kind]
• The claim that
scientific laws refer
to objects that
have invariant
objects and
properties (Ellis
2001, 2002).

27. Biological [taxic]
• The claim that all
members of taxonomic
objects in biology
(species and higher,
subspecies and lower)
have invariant
properties (Devitt 2008,
2010; Hull 1965a,
1984; Rieppel 2010;
Sober 1980; Walsh
2006; Wilkins 2010, In
press).

28. A taxonomy of essentialism
Constitutive Diagnostic Definitional
Physical X X X
Biological X X ?
Psychological X X ?
Human X X ?
Logical — X X
Metaphysical X — X

29. Two modern essentialisms,
and a replacement concept
• Two approaches in favour of essentialism in
biology have been proposed:
• Paul Griffiths’ “historical essentialism”, or
shared ancestral essence (basically,
monophyly)
• Michael Devitt’s “intrinsic biological
essentialism” (basically, developmental
essentialism)
• Dick Boyd’s HPC (homeostatic property cluster)
essentialism: basically a taxon is whatever is
caused by shared homeostatic mechanisms to
persist

30. Is essentialism malignant?
• In Aristotle’s sense, no: there really is a “what-it-was-to-
be” some kind, or else we would not even perceive it as
a kind (observer bias)
• In Devitt’s sense, no, because developmental systems
really do cause progeny to resemble parents in relevant
ways, although the modal claim of necessity is false; all
he needs is a type kind
• In Griffiths’ sense, no, because groups are either
monophyletic or not (and if not, they are not natural
groups)
• In Boyd’s HPC kind, no, because if a group actually is
maintained homeostatically, then that permits variation
(again, an observer bias)

31. Essentialisms outside
taxonomy
• Genetic essentialisms are malignant, but they
are independent from biological science (they
go back at least to medieval times, and are a
side effect of animal husbandry and agriculture)
• What the elite experts say is very different to
what popular texts and nonexpert scientists
might say. I do not deny that essentialism has
played a part in their arguments and ideas

32. Conclusions
• There never was a biological, taxic, essentialism
before or after Darwin until very recently
• Two exceptions (all historical generalisations are
false, including this one): Agassiz’ Platonism and
De Vries’s “elementary species”
• The claim that Aristotelian essentialism is a form of
scientific essentialism arises after Quine’s paper,
based on Popper’s terminology
• Essentialism in a plausible form is not malignant or
antievolutionary
• Scientists and philosophers use history as a weapon