## 1. Species Permanence and Change in Antiquity


### 1.1 Classical Discussions



In many respects, the general idea of species change in Western
thought is an ancient concept. The reflections of Empedocles (ca.
495-35 BCE) and the views of the Greek Atomists among the
Presocratic nature philosophers formed a Classical heritage on which
later speculations could be developed (Kirby 2013). These Presocratic
speculations combined naturalistic accounts of origins with
reflections on the workings of chance-like processes to create
existing forms of life (see the entry ancient atomism). Particularly
as the Presocratic Atomist speculations were restated by the Roman
poet Titus Lucretius (ca. 99-50 BCE) in book five of his *On
the Nature of Things* (Lucretius [RN]), a source was available in
Antiquity and recovered in the Latin West in 1417. This set out a
speculative account of the gradual origin of living beings from an
initial atomic chaos. Through an undirected process, the best adapted
forms are sorted out and those not suited to their conditions are
eliminated



The speculative accounts of the early atomists were, however, opposed
on several levels by the subsequent mainstream Platonic, Neo-Platonic,
Aristotelian, and Stoic philosophical traditions. The writings of
Plato (427-327 BCE), particularly his long creation myth,
*Timaeus*-- the only Platonic dialogue available
continuously in the Latin Western tradition-- provided an
influential non-Biblical source for arguments against the Atomist
tradition. This dialogue serves as the *locus classicus* for
the notion of an externally-imposed origin of living beings through
the action of an intelligent Craftsman (*demiurgos*) who orders
mathematically- conceived matter into a rational cosmos that includes
living beings fashioned in accord with eternal archetypes or forms.
Plato's account initiated the long tradition of reflection that
was continued in Neo-Platonism and in Greek and Roman Stoicism to form
the foundation of the argument that organic beings could not be
explained by chance-like processes either in their origins or in their
complex design. Particularly as developed in the influential writings
of the Greek physician Claudius Galenus (129-200 CE), a long
heritage in the life sciences relied upon anatomy as evidence of
rational design. These interpretations of "teleological
design" interacted in complex ways with Jewish, Christian, and
Islamic Biblical concepts of creation (Sedley 2007). One common
meaning of "teleology" frequently encountered in
discussions of evolution since Darwin--that of externally imposed
design by an intelligent agency (demiurge, nature, God) on
pre-existing matter--originates in these ancient discussions and
is not accurately identified with the Biblical concept of *creatio
ex nihilo* (Carroll 2015).



In Aristotle's (384-322 BCE) seminal biological writings,
the external teleology of a designer-creator was replaced by an
internal teleological purposiveness associated with the immanent
action of an internal cause-- in living beings their informing
soul (*psuche*)-- which functioned as the formal, final
and efficient cause of life (Aristotle, *De Anima* II: 415b,
10- 30 [1984]). Aristotle also did not endorse the concept of an
historical origin of the world, affirming instead the eternity of the
world order (*Physics*, I: 192a, 25-34), which became the
main interpretation of Aristotle's views by a later tradition
(Dales and Argerami 1991).



Another issue that Aristotle treated extensively with relevance to the
conception of species--embryogenesis--also had important
implications for later discussions. In the traditions indebted in some
way to Aristotle's natural philosophy, sexual generation and the
subsequent embryological development of the individual from primordial
matter, is a sequential process that occurs in time under the
teleological action of the soul (*psuche*). In
Aristotle's own account, this soul-as-form is typically derived
from the male parent, but it could also be derived even from the sun,
as employed in his explanation of the origin of
spontaneously-generated forms (Aristotle, *De generatione
animalium*, III: 762a, 20-35).



This theory of the passing on of soul-as-substantial form in
generation also formed the basis of one meaning of
"species" (*eidos*) in Aristotle's biological
works~~.~~ "Species"
in this sense denotes the individualized en-mattered form-as-soul that
is perpetuated in generation eternally. Although connected by a
complex theory of mental abstraction to the universal in thought and
language, a biological species is not a universal, but an eternal
serial sequence of one individual generating another individual
(*De Anima*, II: 415b, 1-10). The importance of this
meaning of *eidos* as distinct from the concept of a universal
in thought and language bears on several issues explored in Sections
3.3 and 3.4 below. 


### 1.2 Medieval Revisions



The implications of Aristotle's complex thought for subsequent
discussions of species, generated by the recovery of his writings in
the Latin West in the twelfth and thirteenth centuries, were varied.
On one hand, Aristotle's apparent metaphysical requirement that
the soul-as-form (*eidos*) be permanent and enduring through
the process of the generation of "like by like" seemed for
much of the tradition to amount to a denial of the possibility that
natural species could change over time in their essential properties,
even though local adaptation in "accidental" properties
was fully possible. Since individual beings were considered to be
dynamic composites of a material substrate and an immaterial and
eternal form, the accidental differentiation of the substantial form
in individuals did not affect the metaphysical endurance of the
species. It also made species extinction metaphysically impossible. In
living beings, the soul-as-form is serially passed on through time in
the act of generation to create an eternal continuity of the form.
This supplied a metaphysical foundation for the notion of species
permanence without reliance on an external creative agency.



In the background of the discussion of the high middle ages was also
the theory of divine creation endorsed in inherited Jewish, Christian
and Islamic thought. This required a distinction between the first
origin of species in historical time, and the normal generation of the
individual. If the origin of species was attributed to divine action,
the temporal emergence of these species was not necessarily
instantaneous. Such a doctrine was the basis of Augustine of
Hippo's (354-430) theory of the original creation of
primordial seeds (*rationes seminales*) of each species at an
original moment in time, but with the emergence of species in
historical time a possibility (Augustine, VI.13.23-25, [GL,
175-76]). This theory of a temporalized creation, put forth
explicitly in detail in his treatise *The Literal Interpretation of
Genesis*, allowed Augustine to argue that species emerged
sequentially in historical time rather than all at once.



The great textual recoveries in the Latin West of Greek science,
medicine and philosophy of the twelfth through the fifteenth
centuries, generally accompanied by Islamic commentaries, introduced
these texts into a theological context that had been strongly defined
by Augustinianism and neo-Platonism. The interplay between this
pre-existent tradition with new philosophical views defined a complex
period of intellectual ferment that defined much of the subsequent
intellectual and scientific history of the West (Gaukroger 2006: chp.
2). The sustained efforts of major synthesizers, such as Thomas
Aquinas (1225-1274), to bring the massive body of
newly-recovered Aristotelian works into dialogue with Christian
Neo-Platonism and Augustinianism, demanded new insights into the
conception of the soul-body relation, the autonomy of the natural
order and the role of secondary causes in the creation of the
world.



Concerning the issue of species-permanence and origin, Aquinas treated
this in dialogue with Augustine's theory of serial creation. As
he comments in his major synthesis, the *Summa Theologiae*:
"New species, if they appear, pre-exist in certain active
powers" (Pars I, Qu. 73, Rep Obj. 3). This claim suggests a
reading of Aristotle that assumed the essential fixity of each
definable substantial form, and the eternity of each species since
creation. But this conclusion must be read in the context of
Aquinas's complex theory of creation and the discussions of the
problem of universals in late Scholastic philosophy (see the entry
medieval problem of universals, and Wilkins 2009: Ch. 3). This context
prevents any simple picture of Scholastic thought concerning the issue
of species permanence, and it cannot be claimed that either Aristotle
or later Scholastics such as Aquinas are responsible for the strong
"essentialist" position often attributed to them in the
literature (R. A. Richards 2010: chp. 2). As developed below (2.2), it
can be argued that the species concept was "hardened" only
in the early modern period with the rise of the mechanical philosophy
and its attendant preformationist embryology. The "strong
essentialist" position often attributed to Aristotle and
Scholasticism (Hull, 1965), is demonstrably a product of later
historical developments (R.A. Richards 2010; Wilkins 2009; Oderberg
2007: chp. 9; Winsor 2006; Lennox 1985, 1987, 2001).


## 2. Early Modern Foundations


### 2.1 Cartesian History of Nature



The re-introduction of Greek and Roman atomism in the Renaissance,
with the recovery (1417) and printing (1473) of Lucretius's
philosophical poem *On the Nature of Things* (Lucretius,
[1968]), introduced to a literate European audience a series of
influential cosmological speculations that included a naturalistic
account of the origin of species integrated into a non-teleological
materialist cosmology that contrasted markedly with the received
Scholastic, Aristotelian, and Augustinian-Platonic traditions. Into
the eighteenth century, these speculations, and those drawn from other
atomist sources (see the entry on natural philosophy in the
Renaissance), were often in the background of novel early modern
reflections on species origins and their possible transformation in
time (Bowler 2003: chp. 2; Oldroyd 1996; Greene 1959).



A new starting point in systematic reflections on the origin of the
earth and living beings, showing both some similarity and also major
differences from atomist speculations, dates specifically from the
synthesis of natural philosophy and metaphysics put forth by
Rene Descartes (1596-1650) in his *Principia
philosophiae* (1st ed. 1644; 2nd ed. 1647). This treatise expanded
and summarized issues he had developed earlier in *Le Monde*
(*The World, or Treatise on Light*), a work published only
posthumously in 1664, with an improved edition appearing in 1677. 



It is important for understanding the subsequent reflections on the
"history" of nature to recognize that these Cartesian
speculations on the history of the earth and solar system were
introduced in the form of a counter-factual hypothesis that explicitly
sought to avoid conflict with accepted theological interpretations of
origins (Descartes 1647 [1983: 181]). In the hypothetical account
offered in the *Principles of Philosophy*, Descartes derived
the earth from a cooled star "formerly...like the
Sun" (ibid.). By its gradual solidification in a great celestial
vortex, the Earth took form. Subsequent drying and cracking formed the
ocean basins, the continents and the mountain ranges.



An outstanding lacuna in Descartes's account, however, was his
failure to incorporate the origins of living beings into his
naturalistic story of creation by natural law. Although manuscripts
display the degree to which Descartes attempted on several occasions
to work out some linkage between his general natural philosophy and
the embryological formation of living beings, these reflections did
not appear in print during his lifetime (Aucante 2006). The
*Principles* simply skips over the issue of a naturalistic
account of the origins of life and the origin of individual species.
Instead in Part IV, devoted generally to the origin and physical
properties of the Earth, he jumps (Proposition 188) from a discussion
of magnetism to a brief allusion to projected Parts V and VI of his
*Principles* that would deal with animals and humans (Descartes
1647 [1983: 275-276]). But the *Principles* only offers a
brief discussion of the various senses and body-soul interaction
similar to that put forth in his early unpublished *Treatise on
Man* (1st Latin ed. 1662, 2nd French ed. 1664). These speculations
were grounded on the concept of a hypothetical statue- machine created
directly by divine action, and possessed immediately of all human
functions and structures (Descartes 1664 [1972: 1-5]).



Descartes's speculations conveyed to his successors at least two
issues relevant to the origin and history of living species. First, by
presenting the historical account of the origin of the solar system
and the world as a counterfactual hypothesis, a means of understanding
the history of nature adapted to the limitations of the human mind,
rather than as a literally true account, Descartes developed the
grounds for a purely fictionalist reading of historical science that
persisted into the nineteenth century (Sloan 2006a). Second, the
integration of living beings into the new natural philosophy of
mechanistic naturalism was left unresolved. If anything,
Descartes's reflections accentuated the problem of providing a
naturalistic explanation of the origins of living beings.



Two traditions can be traced in the wake of Descartes's
reflections. Beginning with the *De solido intra solidum
naturaliter contento dissertationis prodromus* of 1669 [1916] by
the Danish Cartesian Nicholas Steno (1638-86), efforts commenced
to draw the historical origins of living beings into the Cartesian
cosmology, in this case primarily by granting that fossils were the
remains of once existing organisms on an earth that had formed
historically. There was, however, no effort made to account for the
origins of these beings on Cartesian principles (Steno 1669 [1916],
Rudwick 1972, 2005).



A second tradition sought to give a "realist"
interpretation of the history of the earth by reconciling this with
the account of *Genesis*. Such a synthesis was the specific
effort of the English clergyman, Thomas Burnet (1635-1715).
Burnet sought to reconcile a Cartesian-derived historical account of
the origins of the Earth with the creation account of the Mosaic
tradition. In Burnet's account, the Earth began from an original
chaos fashioned by divine action into the existing Earth through a
series of changes that involved the gradual separation of the
continents, the reversal of the poles, and the Mosaic flood. To
explain the origin of living beings, Burnet relied on the
"spontaneous fruitfulness of the ground" in the primeval
Edenic world, similar to the Augustine theory of the created
*rationales seminales*, rather than on the direct creation of
complete forms through divine action (Burnet 1684: bk 2, chp. 2, para.
4, p. 187 [1965: 141]). By connecting this account to the Biblical
story of the first chapter of *Genesis*, Burnet broke with
Cartesian counterfactualism, offering for the first time a presumably
literal interpretation of a Cartesian-style developmental history of
nature that also included the origins of living forms.


### 2.2 Mechanism, Pre-existence Theory and Species Fixity



The various accounts offered in the subsequent "theory of the
earth" tradition, as they were amplified by such natural
philosophers as John Ray (1627-1705), John Woodward
(1665-1728), and William Whiston (1667- 1752), failed to
achieve a consensus position on the question of a naturalistic
explanation of the origins of organisms (Rudwick 1972, 2005). New
reflections on the embryological origin of the individual organism in
the seventeenth-century provided a particular point of focus, and the
reflections on this issue were closely tied to speculations about
species origins.



In its seventeenth-century context, the issue of species origins also
involved debates over the possibility of the spontaneous generation of
forms (Roger 1963 [1997: chp. 2]). The apparent experimental
refutations by Francesco Redi (1626-1667) of spontaneous
generation theory weakened, but did not destroy the foundations of
Burnet's theory. Evidence for spontaneous generation could
always be explained by appeal to Augustine's theory of the pre-
existent "seeds" or "germs".



The extensive empirical researches on the generation and embryological
formation of birds and mammals carried out by William Harvey
(1578-1657), and published late in his life in his
*Exercitationes de generatione animalium* (*Observations on
the Generation of Animals*) in 1651 (Harvey 1651 [1847]), proved
to be a bombshell in this discussion. Harvey's careful studies
claimed to refute on empirical grounds both the Aristotelian
form-matter theory of sexual generation as well as the rival
"two-seeds" theory based on the assumption of equivalent
male and female semen. This latter theory had been embraced by ancient
atomists, by Galenic and Hippocratic medical theorists, and by the
majority of Renaissance physicians. The two-seeds theory had also been
accepted by early-modern atomists such as Pierre Gassendi
(1592-1655) and Nathaniel Highmore (1613-85) (Fisher
2006). As a consequence, when Descartes's own speculations on
embryonic formation were finally published posthumously in 1677, in
which he had also relied on the combination of male and female
*semina* organized by laws of nature and the vortex theory,
they commonly met with derision (see quote from Garden below).
Harvey's detailed embryological enquiries of 1651 had already
seriously undermined the empirical bases of these claims. It is
difficult to find any author who endorsed the solution as offered by
Descartes.



These empirical difficulties with both the main inherited theories of
generation as well as with the new "mechanistic"
alternative accounts of embryogenesis of Gassendi, Highmore, and
Descartes produced a conceptual crisis within the program of universal
mechanism that suggested that universal mechanism could not deal
causally with one of the most important issues in the philosophy of
nature. Another solution needed to be found.



As a consequence of the failure of "mechanistic"
epigenesis, post- Cartesian mechanists resolved this issue with the
theory of "preexistence". Scientific foundations of this
can be traced to the work of the microscopist Jan Swammerdam
(1637-80) in the late 1660s on the basis of his microscopic
observations on developing insects. The philosophical development of
this theory was made by the French Oratorian priest Nicholas
Malebranche (1638-1715), whose influential *Recherche de la
verite* of 1674 recast many Cartesian principles
into a framework of "theistic" universal mechanism
(Malebranche 1674; Gaukroger 2010: chp.2). In this work Malebranche
offered a novel theory of generation which is most accurately termed a
"preexistence" theory. On this view, the new organism is
not generated in secular time, but has pre-existed since the original
creation of the world. This theory, often supported by appeals to
Augustine's theory of the creation of original seeds (see above
Section 1.2), was to become the paradigmatic theory for nearly a
century, and was closely associated with some version of the
mechanical philosophy. Various expressions of the preexistence theory
can be traced into the public teaching and published works of such
influential expositors of academic medicine as Hermann Boerhaave
(1668-1738) of the University of Leyden. The theory is also
endorsed in numerous scientific treatises of the early eighteenth
century. The question of both individual and species origin was by
this theory removed to divine action at the first creation of the
world (Pyle 2006; Roger 1963 [1997: chp. 6]).



At least three variants of the theory of pre-existence can be
distinguished. Two of these assumed the pre-existence of forms in
miniature. The original version assumed the encasement of the
miniature form in the ovaries of the female (Ovism). Following the
discovery in 1677 of spermatozoa by Antonie van Leeuwenhoek
(1632-1723), the theory of the preformation of the embryo in the
male spermatazoa (Vermism) was introduced. These two versions of
"preformationism" generally became the main options one
finds expressed in the professional medical and gynecological
literature of the 1670-1740 period (Pinto-Correia, 1997,
Stephanson and Wagner, 2015). A third alternative, but one which had
few followers in the seventeenth and early eighteenth century until
the 1770s, was the theory of pre-formed "germs", given its
first clear statement by Claude Perrault (1608-80). This
Perrault theory, which closely resembled the Augustinian theory of the
*rationes seminales* (1.2 above), held that the first primordia
of organisms were formed at the original creation as seeds dispersed
in the soil, from which they were taken in with food. Under the proper
conditions and within the correct organisms, these "germs"
became implanted in the ovaries from which they then developed in
response to fertilization. In all three accounts, the act of
fertilization provided the occasion, and not the cause, of the
development of organisms in time.



The theory of pre-existence was seen to solve many problems. First, it
explained the intimate interrelation of structure and function that
seemed to require the existence of parts of the organism in an
integrated system. The heart presumably could not beat without
ennervation, and the nerves could not exist without the heart.
Consequently, as the argument went, the entire organism must
pre-exist. The existence of such integrated systems seemed otherwise
difficult to explain by the sequential development of parts, as
implied in Aristotelian and other "epigenetic" theories of
development. Second, this account was easily harmonized with
theological developments in the seventeenth century, particularly on
the Continent, where the strong influence of Augustinian theology on
Calvinism (Protestant) and Jansenism (Catholic) was most in evidence.
As an example, it provided for the transmission of Original Sin. The
solution that emerged was a "theistic" mechanism that
emphasized God's omnipotence and the corresponding passivity of
nature (Gaukroger 2010; Roger 1993, 1997a, chp. 6]). A third advantage
of the theory of preexistence, at least in the versions that embraced
the "preformed germs" interpretation, was that it allowed
for the appearance of life in secular time, which seemed to be
suggested by the existence of fossil forms. At the same time no
versions of preexistence theory implied any change of species or
development of one species from another in time. Finally, some version
of a theory of the preformation of the embryo could be reconciled with
the best microscopic observations of the late seventeenth and early
eighteenth centuries, as these were reported by such experts on this
instrument as van Leeuwenhoek, Jan Swammerdam, Marcello Malpighi
(1628-1694), and Henry Baker (1690-1774).



These preexistence theories of embryological origin directly affected
the question of species transformism. First, they effectively removed
the organism from the effects of local circumstance and environmental
conditions. Second, they all placed the origin of species, as well as
that of at least the primordia of the individual organism, at a moment
in the original divine creation. A quotation from a contemporary
review article illustrates several aspects of the thesis of
preexistence:



> 
> 
> And indeed all the Laws of Motion which are as yet discovered, can
> give but a very lame account of the forming of a Plant or Animal. We
> see how wretchedly *Des Cartes* came off when he began to apply
> them to this subject; they are form'd by Laws yet unknown to
> Mankind, and it seems most probable that the *Stamina* of all
> the Plants and Animals that have ever been, or ever shall be in the
> World, have been formed *ab Origine Mundi* [from the foundation
> of the world] by the Almighty Creator within the first of each
> respective kind. (Garden 1691: 476-477)
> 
> 
> 



The immediate consequence of this theory was a new rigidity given to
the concept of species that it had not possessed in the Aristotelian
and Scholastic traditions. Preexistence theory reinforced a sharp
distinction between "essential" and
"accidental" properties to a degree not implied by the
prior tradition. At the same time, preexistence theory made it
difficult to explain obvious empirical phenomena, such as monstrosity,
the regeneration of lost parts, the resemblances of offspring to both
parents, evidence for geographical variation, racial differences, and
the existence of hybrid forms such as the mule. It seemed necessary to
attribute these anomalies to divine action at an original creation.
These difficulties in the theory resulted in a variety of criticisms
that were eventually to lead to the downfall of preexistence theory in
its original form, although the theory was to have a long subsequent
history through a modification of the "germ" theory
(Detlefsen 2006; Roger 1997a, chp. 7; Roe 1981).



The dominance of some form of pre-existence theory of generation
between roughly 1670 and the 1740s provides some explanation for the
lack of efforts among natural philosophers to develop transformist
theories of species origins in the same period. A notable exception to
this claim was the Epicurean cosmology resembling some aspects of
Lucretius's poem, developed by the French *philosophe*
Benoit de Maillet (1656-1738) in his privately circulated
manuscript *Telliamed* that was known in French circles for ten
years before its publication in 1748 (Maillet, 1748). In this work de
Maillet offered bold speculations on how sea creatures developed into
land forms over time. Nonetheless, the period before the middle of the
eighteenth century was dominated by a theory of organic generation
that effectively precluded the naturalistic development of species.
The development of scientific transformism can be seen to be
intimately tied to new theories of generation, and also to the
development of "active" rather than "passive"
conceptions of matter.


### 2.3 Newtonian Revisions



The introduction of Newtonian natural philosophy into this discussion
had ambiguous consequences depending on the interpretations given to
Newton's natural philosophy. Newton's
*Philosophiae naturalis principia mathematica*
(*Mathematical Principles of Natural Philosophy*) of 1687, with
subsequent revised editions in 1713 and 1729 (Newton 1729 [1999]),
developed a fundamental critique of Cartesianism, and also introduced
the concept of attractive forces, able to act over a distance, into
physical explanations. Extending the concept of "active
powers" to the micro-level in his *Opticks* of 1704
(English), with important revisions in editions of 1706 (Latin), 1717,
1721, and 1730 (Newton 1730 [1952]), Newton introduced into biological
discussions new issues that played out in complex ways in the
subsequent decades.



On one reading of Newton, his conception of active forces introduced
back into life science a concept of "dynamic" matter that
could be used as a warrant for a new vitalistic embryology and even a
non-mechanistic conception of nature possessed of intrinsic powers
(Schofield 1970: chp. 9). This option was followed out by many French
medical writers who used Newtonian arguments to ground a
"vitalistic" medical theory, an interpretation
particularly developed at the University of Montpellier in the early
decades of the eighteenth century (Wolfe 2014; Gaukroger 2010: chps.
10-11).



But in the more "mechanistic" interpretation of
Newtonianism, this retained the inert character of matter and endorsed
many of the main features of Cartesian biomechanism, but with the
addition of mathematical quantification and some use of attractive and
repulsive microforces (Schofield 1970: chp. 1). In this tradition of
interpretation, one finds a commitment to mechanistic preformationism
and even strong "preexistence" theory. This can be
followed in the medical theories of Hermann Boerhaave, Archibald
Pitcairne (1652-1713), Richard Mead (1673-1754), and other
Newtonian iatromechanists who typically had contact with the great
Dutch medical schools (Guerrini 1987).



Newton had also argued in the long thirty-first Query to the
*Opticks* against "World-Building" of the Cartesian
form, as discussed above. Newton saw this as claiming that the world
"might arise out of a Chaos by the mere Laws of Nature"
(Newton 1730 [1952], 378), and condemned this as
"unphilosophical" (*ibid*., 401). Revival of
realistically interpreted historical cosmology in the eighteenth
century involved a clear break with these Newtonian strictures. This
shift will be developed in the following section.


### 2.4 Revitalizing Nature



The development of new conceptualizations of the relation of organic
beings to the history of the world, and the relation of species
permanence to this history, was achieved in the eighteenth century.
This included the breakdown of universal mechanism, the introduction
of dynamic theories of matter, new theories of embryological
formation, and a reconceptualization of the relation of time to the
material world. It also involved the formulation of progressive and
developmental, rather than "degenerating", conceptions of
the history of life. The following discussion will selectively examine
aspects of these developments. The reader is referred to major recent
historical syntheses for further development of the more general
intellectual and scientific context (Zammito 2018; Gaukroger 2010;
Reill 2005; Rudwick 2005).



In several respects these developments are connected in some way to
the introduction of dynamic conceptions of matter that emerged in the
interplay between Newtonianism and Leibnizianism in the early decades
of the eighteenth century, particularly in French discussions (Shank
2008). As described in the previous section, Newton's
introduction in the Queries to the *Opticks* of the concept of
active microforces that could explain microchemical and electrical
phenomena opened up this discussion. The other great natural
philosophy developed on the Continent by Gottfried Leibniz
(1646-1716) and systematized and expanded into an influential
systematic philosophical program by Christian Wolff (1679-1754),
elaborated a more complex theory of matter that distinguished between
the properties of phenomenal "matter" as conceived by
Newton, and those of a more fundamental active and
teleologically-directed "substance", grounded in force
(*vis*). In physics this development played out on the
Continent in the *vis viva* controversy, which was concerned
initially with the conservation of force in collisions. It was then
extended to more fundamental metaphysical issues that had a complex
effect on the life sciences.



In the life sciences, these issues were manifest in debates over the
role of vital powers in the explanation of living properties, as these
were developed particularly in French discussions in the complex
interactions of Newtonian and Leibnizian-Wolffian natural
philosophies. An influential example of this synthesis is
Emilie Du Chatelet's (1706-1749)
*Institutions de Physique* (first ed. 1740, second ed. 1742).
These hybrid Leibnizian- Newtonian syntheses, bringing together
aspects of Newton's "active" forces with the monad
and substance theory of Leibnizianism, were subsequently extended into
discussions of embryology by Pierre de Maupertuis (1698-1759),
and as will be developed in the next section, by Georges-Louis
LeClerc, Comte de Buffon (1707-88) in the 1740s. 



It is in the context of these discussions that we encounter the first
early modern systematic speculations connecting naturalistic theories
of earth history, embryological development, and changes of organic
species in response to external changes of conditions of life. These
connections develop directly out of critiques of the preexistence
theory of generation by Maupertuis and Buffon, who in different but
related ways reformulated the "mechanistic" epigenetic
embryology previously advocated by Descartes and Atomist theorists.
Similar to these discarded theories (see above, Section 2.2), the
existence of equivalent male and female "seeds" was
postulated, which were then assumed to combine in sexual generation to
form the embryo. The new eighteenth-century versions supplemented
these seventeenth- century accounts with a novel role for dynamic
conceptions of matter and inherent organizing forces. In the case of
Buffon, these claims were supported by controversial microscopic
observations that presumably refuted the opposing claims made by
William Harvey a century earlier (Sloan, 1992a). We can conveniently
date these developments from the speculations of Pierre de Maupertuis,
put forth in two treatises, the better known the *Physical
Venus* (*Venus physique*) published in 1745
(Maupertuis 1745 [1966]). To deal with the difficulty of explaining
how atomistic seeds derived from the male and female could be formed
into the complexity of the embryo, Maupertuis drew upon a version of
Newtonian attraction inherent in these seeds which also included
elements of Leibnizian monad theory. In his last formulation of 1751
he expanded on this with the claim that the particles themselves were
endowed with an internal principle that led them to arrange themselves
to form specific parts of the fetus. Maupertuis' dynamic
"epigenesis" incorporated both mechanism and dynamic
materialism (Terrall 2002: chp. 7; Hoffheimer 1982).



There are at least three ways in which the change in embryological
theory instituted by Maupertuis, and subsequently elaborated by
Buffon, proved to be relevant to the broader question of the
historical transformation of species. First, this new account of the
embryological origin of the individual organism meant that it actually
is organized in historical time rather than pre-existing and simply
unfolding at an opportune moment. Second, it involved a theory of
material inheritance that explained the passing on of physical traits
from one generation to the next through the transmission of particles
of matter. Third, the conservation of the identity of the species is
guaranteed only by the accurate transmission of this material
inheritance. If this transmission is affected by external
circumstances in any way, significant historical change in the lineage
of ancestor and descendant is possible. These options, opened up by
Maupertuis's speculations, were subsequently developed within an
institutional setting by Buffon.


## 3. Buffon's Transformation of Enlightenment Natural History



The complex set of issues described in the preceding discussion were
all brought together in the work of Buffon. In a remarkable career
transition in 1739 in which he moved from his position as a pensioned
mathematician in the Paris Royal Academy of Sciences, to the
Directorship of the King's Garden and Natural History Cabinet
(*Jardin du Roi*) in Paris, Buffon brought with him to the
domain of natural history and to his reflection on issues in biology
his deep familiarity with the major theoretical debates dividing
Newtonians, Cartesians, and Leibnizians in his era. He was also
intimately acquainted, through his friend Maupertuis. with the debates
over generation theory and theories of the earth. He fashioned these
ingredients into a set of new perspectives that were to define his
novel approach to the life sciences over the last half-century of the
Bourbon monarchy. In the interpretation of this article, Buffon is the
major figure to put together a set of issues that formed the
pre-conditions for transformism in biology, although he would never
himself move into this theoretical region. Through his immensely
popular writings, translated into all major European languages, he
exerted an influence on discussions that ranged from St. Petersburg in
Russia to Virginia in the American colonies.



Buffon was able to exert such influence through the concrete
institutional basis provided by the *Jardin du Roi*, with its
attendant large *Cabinet* of specimens collected from all over
the world. Under his leadership was created the pre-eminent
eighteenth-century center of research into comparative anatomy,
chemistry, mineralogy, botany, and biogeographical study (Spary 2000).
By providing an institutional setting for these inquiries, the
speculations and theoretical reflections of eighteenth-century natural
historians could be subjected to organized critique and specialized
examination in a context not found elsewhere in the natural-historical
sciences of the period. Buffon's theoretical vision provided a
concrete framework against which those immediately associated with the
*Jardin* were able to develop further reflections on such
issues as the nature and duration of species, the significance of
comparative anatomical studies, the historical relationships of forms,
the meaning of fossils, and the systematic relations of living beings
to one another. Only Buffon's contemporary, Carolus Linnaeus
(1707-1778), Professor of Medicine and Botany at the University
of Uppsala in Sweden after 1741, had similar authority in the domain
of natural history, and Linnaeus did not have the resources and the
institutional authority that characterized the *Jardin* in the
last days of the Bourbon monarchy.



This simultaneous emergence of Linnaeus and Buffon in the natural
historical sciences of the middle Enlightenment created a major
rivalry of traditions of inquiry that would play out on several
fronts. In Buffon, one had the model of the grand and eloquent
theoretician of nature who developed major themes in Enlightenment
natural philosophy and applied these to biological topics. In
Linnaeus, one had a pious systematizer of the natural world of his
era, whose monumental *System of Nature* (first edition 1735),
along with numerous other works, formed the basis for modern
biological classification. Their different approaches set the stage
for a major theoretical conflict of traditions in natural historical
science that would eventually be synthesized in the nineteenth century
(Hoquet 2007).


### 3.1 Buffon and the Methodology of Natural History



Buffon's development of a broad theoretical inquiry into natural
history within the framework of a state-sponsored institutional
structure warrants the special attention given here to his
contribution in the history of evolutionary theory. These included:
(1) his methodological revolution in the epistemology of the
natural-historical sciences; (2) his analysis and proposed solution to
the problem of animal and plant generation; (3) his
reconceptualization of the concept of biological species; (4) his bio-
geographical approach to the issues of animal distribution and
variation; (5) his renewed theoretical attention to issues of
cosmology and the "theory of the earth;" and finally (6),
his concluding synthesis of earth and life history in the grand
naturalistic account published as his monumental *Les*
(originally *Des*) *Epoques de la Nature*
(*Epochs of Nature*) of 1778-9, which provided a model
for similar syntheses of the nineteenth century. Through this
combination of several lines of earlier inquiry, Buffon posed a series
of theoretical questions that were further explored by important
successors associated with the Paris Museum in the nineteenth century
and by natural historians of the eighteenth and early nineteenth
century more generally.



In his position as a natural philosopher, in dialogue with the works
of Newton, Descartes, Leibniz, Clairaut, Du Chatelet, the French
*Encyclopedists*, and major English philosophers of his period,
Buffon explored foundational methodological and philosophical
questions of the Enlightenment in combination with his analysis of
empirical questions. One expression of this wider vision was the
unusual way in which he sought to validate the inquiry into natural
history in relation to a naturalized epistemology that scholars have
seen as novel for its time (Hoquet 2005; Sloan 2006b; Roger 1997a,
chp. 9, 1997b, chp. 6). In developing a new methodological approach to
natural history, Buffon claimed to ground his arguments on a form of
empirical certitude--"physical truth"
[*verite physique*]--attained through inquiries
into the concrete relations of beings in their material relations.
This he opposed to the "abstractions" of mathematical
physics, extending the Leibnizian-inspired critique of Newtonian
methodology as developed in Emilie Du Chatelet's
(1706-1749) *Institutions de Physique*, a work Buffon is
known to have read and admired as he made his transition into his
career in natural history (Chatelet, 1740). Developing this
argument in a long "Discourse on Method" that opened the
first volume of his *Histoire naturelle, generale et
particuliere, avec la description du cabinet du roi*
(Buffon [HN]) (1749), Buffon argued that a science based on repeated
observation of concrete material relations of bodies can achieve a
degree of epistemic certitude which surpasses that available from the
mathematical analysis of nature (Hoquet 2005; Grene & Depew 2004;
Roger 1997a, chp. 6; Sloan 2006b). On the basis of this novel
epistemological framework, oriented to the search for
"physical" truth, Buffon thus directed natural history
away from a primarily classificatory project. The latter project,
exemplified by the work of his contemporary Linnaeus, Buffon
criticized for imposing "abstract" categories on nature.
In its place, Buffon sought to analyze living beings in relation to
their material conditions of existence. This was to be focused on
their reproductive relationships, biogeographical distribution, and in
his later work, on their connections to cosmology and historical
geology.



These insights formed an epistemological framework for the subsequent
development of the *Histoire naturelle.* In these discussions
Buffon dealt both with issues in the foundational epistemology and
methodology of the natural-historical sciences as well as with the
generalities and specifics of organic beings. Although the work was
originally intended as a survey of the entire range of animals,
plants, and minerals, in its actual realization, it was more limited.
The first series of fourteen volumes (Buffon HN) appeared between 1749
and 1767 and dealt with the genesis of the solar system and the earth,
the generation of animals, the varieties of the human species, and the
natural history of the primary quadrupeds and apes. The main quadruped
volumes of the first series, beginning in 1753, were written in
collaboration with the comparative anatomist Marie-Louis Daubenton
(1716-1800). A series of seven volumes of Supplements
(1774-89) offered additional reflections and additions to these
articles and expanded on his views on the history of the earth, the
quadrupeds, and anthropology. These also reported on experiments on
the strength of wood and the cooling of metals that he applied to
dating the age of the earth. In the fifth supplementary volume (1778),
Buffon presented his grand synthesis of cosmology, earth history, and
the history of life, the *Epoques de la nature* (English
trans., Zalasiewicz et. al, 2018) (see below, 3.3). An additional five
volumes (1783-88) dealt with issues of mineralogy, chemistry,
fire, and the main forces of nature, especially electricity and
magnetism.


### 3.2 Buffon on the Generation of Organisms



The concrete manifestation of Buffon's combination of novel
methodology and empirical inquiry is first displayed by his treatment
of embryological generation in the second volume of his *Natural
History* (1749). These principles also underlie his unusual
analysis of the meaning of "species" in natural history.
In both instances, the notion of epistemic certitude gained from a
"constant recurrence" of events plays a fundamental role
in his reflections. Following the lead of his friend Maupertuis,
Buffon also endorsed the theory of the male and female seeds to
explain sexual generation, deriving the origin of the embryo from the
mechanical mixture of these ingredients. Amplifying upon
Maupertuis's prior speculations (see above Section 2.4), he
explained the organization of the particles of these two seeds into a
structured whole through microforces closely identified with Newtonian
attractive forces that formed an organizing force-field, an
"internal mould", that assimilated matter in the proper
order for embryological development. Viewed in longer historical
perspective, Buffon's theory of the internal mould functioned in
a way similar to Aristotle's notion of an immanent substantial
form, and was likely influenced by Aristotle's discussions in
*De generatione animalium* (see above Section 1.1). This
"mould" serves as an immanent principle of organization
that acts in company with matter to structure the unified organism by
gradual development. The internal mould also guaranteed the
perpetuation of like by like over time. Unlike Aristotle's
substantial form, however, Buffon's internal mould is without an
internal finality in its action. It is also not a principle of
vitalization.



To explain the formation of the fetus, Buffon was conceptually
required to attribute some new powers to matter to account for
organization. In pursuing this option, he broke with universal
mechanism and the assumption of the passivity of matter that was an
intrinsic component of the mechanical philosophy and some
interpretations of Newtonianism (see above Section 2.3). There are
also important similarities of his new "vitalism" to that
found in Leibnizian discussions such as was expounded in the
*Institutions de Physique* of Emilie Du Chatelet
in 1740 (Sloan 2019). To give a plausible account of embryological
formation, vital properties therefore had to be attributed to a
specific kind of matter confined to living beings, the *organic
molecules*, which had their own inherent dynamic and specifying
properties.



The introduction of the concept of "vital" matter by
Buffon, even with restrictions on its actions, represents an important
development in the history of the life sciences of this period. It
broke with the uniformity of matter assumed by the Newtonian,
Gassendist, and Cartesian traditions, and in a limited way it
positioned Buffon at the opening of the "vitalist"
revolution which initiated the first reflections on genuine species
transformism, even though Buffon himself never moved into this new
conceptual domain (Reill 2005: chp. 1).



In his original presentations, Buffon posited that these internal
moulds and specifying organic molecules originated by divine creation.
As the *Natural History* progressed, however, Buffon
increasingly viewed the organic molecules to be formed from an
original undifferentiated "brute" matter, and the internal
moulds themselves were seen to arise spontaneously, obtaining their
specificity of action purely from the differential forces of
attraction between different shapes of organic particles (Buffon
"De la Nature. Seconde vue", 1765, [OP, 38-41]).


### 3.3 Buffon and the Degeneration of Species



It is in the context of his proposed solution to the issue of organic
generation that Buffon then addressed the issue of organic species and
their permanence. In the fourth volume of the *Natural History*
(1753), devoted to the large domestic quadrupeds, Buffon first raised
the option of species transformism, only to reject it. In the article
"The Ass", devoted to the domestic donkey, Buffon drew
attention to the close anatomical similarity between the horse and the
ass, as revealed by his collaborator Daubenton's anatomical
descriptions. This similarity strongly suggested an underlying unity
of plan of all the quadrupeds, a similarity raising the possibility
that all quadrupeds might have been derived in historical time from a
single stem (*souche*) which "in the succession of time,
has produced, by perfection and degeneration, all the other
animals" (Buffon 1753, [OP, 355]). In a move that has confused
commentators every since, Buffon then rejected this possibility and
instead argued that because of the infertility of hybrids, species
must have been distinct from the beginning.



The explanation of Buffon's initial 1753 rejection of
transformism, and his subsequent development of proto-evolutionary
views as the *Natural History* progressed, has taken many forms
(Bowler 2003: chp. 3; Lovejoy 1911 [1959]). The argument of this
article is that both Buffon's initial rejection of transformism,
and his subsequent development toward the acceptance of historical
species change reflect a coherent and consistent development of his
concept of "physical truth" (see above Section 3.1).
Drawing on his emphasis on serial recurrence and material connection
as the foundation of physical truth, the species is maintained in time
and given its ontological reality by the recurring passing on of the
internal mould which shapes the organic molecules into a new organism
in time. 



This analysis implied for Buffon a significant redefinition of the
concept of an organic species, a redefinition that has affected the
tradition of natural history and biology since the 1750s. Buffon
explicitly rejected the long-accepted meaning of 'species'
as a universal-- or, in modern parlance, a "class"
concept, constituted by a set of individuals on the basis of
possession of explicit defining properties. This was the meaning
implicit in the Linnaean classification of his time. This concept
Buffon criticized as an "abstract" meaning of species. By
contrast, Buffon defined a species in natural history exclusively as
the historical succession of ancestor and descendant linked by
material connection through generation. Such a species
is,"... neither the number nor the collection of similar
individuals which forms the species; it is the constant succession and
uninterrupted renewal of these individuals which constitutes it"
(Buffon 1753, [OP, 355]).



The empirical sign of this essential unity of the species over time is
the ability of its members to interbreed and produce fertile
offspring, a criterion that takes precedence over similarities of
anatomy or habits of life. The horse and ass must be two different
species because they cannot interbreed and produce fertile offspring,
whatever may be their anatomical resemblances. The dogs, on the other
hand, must, in spite of great morphological differences between
breeds, constitute one species because of their interfertility. 



In setting forth this new meaning of 'species' in natural
history, and distinguishing it from the alternative meaning of species
as a logical universal, Buffon was doing more than distinguishing the
"category" from the "taxon" as these terms
have come to be understood in contemporary philosophy of biology. In
an important sense, Buffon introduced an *opposition* between
these two meanings of "species" found in the tradition
reaching back to Aristotle (see Section 1.1 above), granting
"reality" in biology only to species conceived as material
successions of individuals sharing in the same internal mould spread
out in time. By contrast, Buffon considered the understanding of
species in the sense of a universal class concept to be
"abstract" and "artificial".



This explicit opposition of two meanings of "species"
introduced by Buffon, divorcing concepts previously linked together by
a complex relation of thought and world within the Aristotelian and
Scholastic discussions, has been seen by some commentators as marking
the introduction of a fundamental confusion over the conception of
species in subsequent discussions in the biological literature. This
is at least one of the underlying causes of the so-called
"species problem". In their historical extension, these
issues continue to generate contemporary disputes that oppose
conceptions of "species as sets" to those of
"species as spatio-temporal individuals" (Dupre
1993; Ereshefsky (ed.) 1992; Ghiselin 1997; Hull 1999; R.A. Richards
2010; Sloan 1987, 2013; Stamos 2003; Wheeler & Meier (eds) 2000;
Wilkins 2009; R.A. Wilson (ed.) 1999; and the entry on species in this
encyclopedia).



The subsequent developments in Buffon's thought toward what an
older tradition of scholarship mistakenly interpreted to be
"evolutionism", involved the gradual broadening of his
natural-historical or "physical" species to include wider
and wider degrees of material relationship. This expansion of his
original species concept Buffon expressed in the language of a
"degeneration" of forms in time in response to
environmental conditions.



The encounter with a wide body of new data from the colonies and
exploratory voyages returned to Paris during the course of the writing
of the *Natural History* impressed Buffon with the degree to
which species seemed to be affected by external circumstances such
that from a single source numerous "degenerations" could
arise in some groups. This formed the conceptual basis for his concept
of a *race* as distinguished from a Linnaean *Variety*.
A "race" in the Buffonian sense was a historical
degeneration from a common ancestor that maintained material and
historical connection to this common source form. But this lineage
could undergo substantial and quasi-permanent hereditary
differentiation into different lineages, with the cause of these
degenerations explained by slight changes in the organic molecules
produced by varying environmental circumstances as a given physical
species migrates to new environments. These slight changes in turn
affected the internal mould. Developed in greatest detail in his long
article, "On the Degeneration of Animals" in volume XIV
(1766) of the *Natural History*, Buffon's theory of the
degeneration of species extended so far as to allow the lumping of the
quadrupeds of both the Old and New worlds into a limited number of
primary "families" (*familles*) and
"genera" (*genres*) that from points of origin in
the Northern European hemisphere, have degenerated in time in response
to migration to new locales. By including human beings in this
naturalistic scenario in his later writings, and assuming that human
lineages underwent similar degenerative changes as they migrated from
their postulated point of origin of human beings in the Caucasus,
Buffon's theory played a major role in the development of
Enlightenment racial theory (Sloan 1973, 2014).



Buffon subsequently made some steps toward combining the thesis of the
historical degeneration of species with his theory of historical
cosmology in his late *Des* (subsequently *Les*)
*Epoques de la Nature* first published in
*Supplements* volume 5 (1788), and subsequently issued
separately in 1789. In this treatise he reworked his earlier
speculations on the "theory of the earth", first set out
in 1749, adding to this a historical chronology of the age of the
earth determined experimentally in the 1770s by quantitative studies
on cooling spheres of metal. In this imaginative synthesis, and
drawing on an allegorical reading of *Genesis* 1, Buffon
combined a history of the Earth with a historical sequence of the
emergence of living forms (Buffon 1779 [1988]; Zalasiewicz et al.,
2018). In doing so he expanded the time scale of earth history
considerably beyond the accepted "Mosaic" chronology of
less than 10,000 years from the beginning of the world to the present,
to an estimate of approximately 75,000 years in the published version,
and over two million years in his draft manuscript. In this treatise
Buffon offered a naturalistic solution to the two inherited Cartesian
dilemmas. First, his schema was offered as a realistic account. The
Cartesian language of counter-factualism has disappeared. Second, he
integrated the history of living forms into this comprehensive history
of the world. Further naturalizing his theory of the internal moulds
and organic molecules, both were now seen to arise by natural laws
from the natural attraction of different shapes of matter and from the
changes in matter as the earth cooled from its origin in matter cast
off by the sun. Animals first originated by the spontaneous clumping
together of these organic molecules on the cooling earth (Buffon 1779
[1988]: Fifth Epoch).



The *Epochs* also offered a schema for a historical sequence of
forms that appear sequentially in a series of six major
"epochs" to which Buffon gives precise dates of duration.
This begins with the origin of the earth from a cooled star, and then
describes the beginning of living nature with marine life and plants
in the early stages of the earth's history, terminating with
present forms His account even suggested a naturalistic origin of
human beings, although this issue is left vague. Humankind appears,
without explanation in the text, in a non-paradisal state in the
northern latitudes of Eurasia, surrounded by ferocious animals,
earthquakes and floods, and in a primitive social condition that
required collaboration for survival. Buffon's liberal use of a
form of spontaneous generation that allowed for the origin of even
major animal groups from the clumping together of organic molecules as
the earth cooled, rendered the actual derivation of forms from
previous forms unnecessary. In several respects, the development of
genuine transformist theories by Buffon's successors required a
much more restricted use of the possibility of spontaneous generation.



### 3.4 The Reception of Buffon's Natural History



Beyond the confines of the Paris *Jardin*, the reflections
inspired by Buffon for wider discussions of the late Enlightenment
natural history were complex. The reception of his *Les
Epoques de la Nature*, for example, was uneven (Roger
"Introduction" in Buffon 1779, [1988, cxxiv]). Although
the main body of the *Natural History* was translated three
separate times into English (William Kenrick and J. Murdoch
[1775-76]; William Smellie [1785], James S. Barr [1792], the
*Epochs* was never translated into English until recently
(Zalasiewicz et al., 2018), and it seems to have played an
insignificant role in anglophone discussions, in contrast, for
example, to the major impact of the works of Linnaeus, which received
a wide British exposition and translation. The boldly speculative
character of the *Epochs* was also at odds with the new
professionalized inquiries into geology and natural history undertaken
by a younger generation of naturalists who may have adopted
Buffon's naturalism and extension of geochronology, but not his
grand rhetorical style (Rudwick 2005: chp. 3).



Historical research has shown, however, that the *Epochs* had
an influential history in the Germanies (Schmitt, 2019). The treatise
was quickly (1781) translated into German at St. Petersburg and it
seems to have played an important role in the development of German
historicism (Reill 1992). Although linkages are in need of further
scholarly research, the impact of Buffon's *Epochs* on
the historical transformism sketched out a few years later by Johann
Gottfried Herder (1744-1803) in the first volume of his
magisterial *Ideen zur Philosophie der Geschichte der
Menschheit* (1784- 91) is suggested by several lines of
evidence (Zammito 2018: 180-185, 2018b).



Herder departed markedly from Buffon, however, in developing his own
historical theory of the cosmos and the development of life, and
eventually of human culture, on a framework of teleological progress
based on a "vital" theory of matter. For Herder, not only
the individual organism, but nature as a whole develops under the
causation of an internal organic force that leads it to develop higher
and higher stages of life, eventually resulting in the ultimate
development of humankind in history.


## 4. Early Nineteenth-Century Transformism



By the early nineteenth century, one can follow several lines of
reflection admitting some form of species transformism and a
historical development of life. In the Germanies, Herder's
reflections formed a major ingredient in the development of German
*Naturphilosophie* and "Romantic" science that was
expanded in the writings of Johann Goethe (1749-1832),
Friederich Schelling (1775-1854), Gottfried Treviranus
(1776-1837) and several others who advocated some version of a
historically progressive philosophy of nature with at least the
"development" if not actual transformism of species in
time (Zammito 2018: chps. 8,9,11; R. J. Richards 2002: chps. 2, 3, 8).
In the British Isles in the same period, the reflections in the second
volume of his *Zoonomia, or the Laws of Organic Life*
(1794-1796) of Erasmus Darwin (1731-1802), grandfather of
Charles Darwin, offered a theory of species development based on a
concept of dynamic living matter. These multiple lines of late
eighteenth-century reflection advocating some form of a general
transformism of species and a history of living nature, each of which
can be followed out in detail, can be differentiated from the
institutional framework of discussion established in France after
Buffon at the *Museum nationale d'histoire
naturelle* in Paris, the post-Revolutionary successor to the
*Jardin du roi.* These institutional developments supplied a
new precision and a concrete material context for the professional
discussion of transformist question as it emerged in the nineteenth
century. This institutional framework of French discussion will be
emphasized in the following while acknowledging the broader context of
discussion outside of France. 



Buffon's leadership of the *Jardin* ended with his death
in April of 1788 on the edge of the massive social, political and
scientific changes that were to overtake France a year later. As the
only major French scientific organization to survive the dismantling
of all other institutions of privilege by the National Convention in
the summer of 1793, the reconstituted and reorganized
*Museum nationale d'histoire naturelle* provided
an unusual context for the further development of transformist
theories (Blanckaert et al. [eds] 1997). In its new form, the
*Museum* created an institutional context in which
several aspects of Buffon's grand undertaking in natural history
could be refined and deepened in the decades following his death
(Corsi 1983 [1988: chp. 1]). In the Revolutionary context of the new
Republic, the work of Linnaeus and his classificatory approach to
natural history, admired by Jean-Jacques Rousseau, but overshadowed
before 1789 by the authority of Buffon, was elevated at the
*Museum* to a new level of authority. The two rival
leaders of natural history in effect became for the French naturalists
what George Cuvier (1769-1832) later described as "two
founts" from which they jointly drew their inspiration.



The Revolutionary reorganization of the *Jardin* also created a
new kind of specialization of research and disciplinary division
within what had previously been conceived of as "natural
history". The reorganization of 1793 established within the
*Museum* twelve separate Chairs of equal status that
gave specific individuals control over portions of the collections and
the research work done within these divisions that instituted new
disciplinary specializations within natural history. "Mammals
and Birds" were placed under Etienne Geoffroy Saint-Hilaire
(1772-1844). "Reptiles and Fishes" were assigned to
Buffon's understudy Bernard de Lacepede
(1756-1825). "Human Anatomy" was given to Antoine
Portal (1742-1832). The creation of a new Chair of Comparative
Anatomy, with an attendant separate museum established in 1802,
provided the position for the young Alsatian zoologist Georges Cuvier
(1769-1832). The large conglomerate of forms, known previously
only as "Worms" (*Vers*), was placed under the
control of Buffon's one-time understudy Jean Baptiste Pierre
Antoine de Monet, Chevalier de Lamarck (1744-1829). Other chairs
in botany, paleontology, comparative physiology, and anthropology were
established, or would be developed in the nineteenth century. All
these new institutional structures subdivided traditional
"natural history", and facilitated professionalized
inquiries into specific areas of life science that related to the
nature of species, the interpretations of the classificatory systems,
and to the history and biogeography of the earth (Corsi 1983 [1988:
chp. 1]; Appel 1987).


### 4.1 Lamarckian Transformism



It is in this context, and through his position as the first holder of
the Chair of "Worms" that Jean Baptiste de Lamarck
developed during his tenure the first coherent theory of species
change over historical time, eventually known by the new
term--*transformisme*. Lamarck in many respects warrants
the claim to be the first genuine evolutionary thinker situated within
a professional scientific institution.



Lamarck's theory of species transformism emerged gradually in
his annual *Museum* lectures on the "animals
without vertebrae" that commenced in 1794. As the new occupant
of the Chair dedicated to this vast array of forms, Lamarck undertook
in 1794 a massive reorganization of the *Museum*
collections of these animals. To accomplish this, he adapted for their
taxonomic organization the method of arrangement of the plant groups
he had developed in his earlier work on French botany (Lamarck, 1778),
created during his formative years when he worked in the
*Jardin* as a botanist. In this early botanical work he had
ordered groups serially from most complex flowering plants to most
simple fungi. Lamarck then adopted a similar method for his initial
arrangement of the invertebrate groups of animals.



But the complexity of the invertebrate groups prevented any simple
linear arrangement, and the complex classification of the
invertebrates Lamarck worked out provided him with an empirical base
from which his transformist theory was subsequently developed
(Burkhardt 1977). Expounded though his annual *Museum*
lectures, Lamarck was able to develop these arguments in interaction
with the wide array of collections of invertebrate animals at the
*Museum*.



In view of the many interpretations of Lamarck's views that have
emerged since the public presentations of his theory in his 1802
*Recherches sur l'organisation des corps vivants*,
and in developed form in his 1809 *Philosophie Zoologique*
(*Zoological Philosophy,* [Eng. 1914, 1963]), and in the
"Introduction" to his *Histoire naturelle des animaux
sans vertebres* (*HASV*, 1815-1822), the
primary features of Lamarck's reflections need to be carefully
detailed. In most fundamental terms, his theory of species change was
tied to his *reversal* of the taxonomic ordering of forms
originally presented in his early systematic arrangements. In his
original classifications, these groups were ordered in a series of
"principal masses" (*masses principales*) that
began with the most complex invertebrates forms (cephalopods) and
terminated in the least organized (polyps--hydra, sponges,
anemones). By 1800, Lamarck decided that this ordering was artificial,
and that the "natural" arrangement was a complex series
running from simpler forms to those more complex. The evolutionary
theory he subsequently developed involved the claim that this new
order of arrangement was also representative of the *historical
sequence* by which forms had been generated one from another over
time.



These novel conclusions were first presented in the
*Museum* lectures of 1800, and then were developed in
more detail in print in his *Recherches* (1802), with the full
exposition in his *Philosophie zoologique* and the
*HASV*. Some further significant elaborations of his ideas were
then expressed in his many articles for the second edition of Joseph
Virey's *Nouveau dictionnaire d'histoire naturelle*
(1817-19) (Lamarck 1817-19 [1991]). His theoretical
conclusions were also concretely displayed in the arrangement of
specimens in the main zoology gallery of the *Museum*
over which he had primary control. The following claims formed the
core of his mature theory:


1. The origin of living beings is initially through spontaneous
generation. This action is confined, however, to the origins of the
most structurally-simple forms of life--infusoria and polyps. All
subsequent forms necessarily havae developed in some way in time from
the elementary beginning in these simplest forms.
2. The causal agency behind this "ascending", rathr than
"degenerating", history of life over time is supplied by
the activity of dynamic material agencies--caloric and electrical
fluids. The entry of these active material agencies into inorganic
matter produces the spontaneous generation of the elementary plants,
the microscopic infusoria, and the simplest polyps. This also provides
the causal impetus by which these simple forms can give rise to forms
of higher complexity, moving to the radiarians, and so on up the
series. Moving beyond the distinction of "inert" and
"living" matter of his mentor Buffon, Lamarck's
theories generally can be considered "vitalist" in
inspiration, in that they attribute a genuine dynamism to living
matter and grant it the ability to create new forms and structures
through its inherent powers. Lamarck denied, however, any appeal to
special supperadded vital forces, and his reliance on the causal role
of dyanmic Newtonian aetherial fluids grounded his theory on a concept
of active matter that can be termed a theory of "vital
materialism".
3. The Lamarckian "series" that underlies Lamarckian
transformism is not a linear series of species and genera, but a
hierarchy of primary organizational plans that emerge from
lesser-organized plans. This moves generally from simpler forms to the
more complex and results withint the animal kingdom in an axis of
fourteen primary groups, terminating in the higher vertebrates, the
mammals. This parallels the "natural" order of
classification of groups he had developed in his taxonomic system.
Position in the series is defined primarily in terms of the structural
and functional elaboration of the nervous system. Also involved in
this dynamic ordering of groups, but only at the highest levels, are
the internal functions of "will" and "effort"
in the development of life.
4. The best-known feature of Lamarkism in the subsequent
tradition--the theory of transformism via the inheritance of
acquire characters--functions as a subordinate, diversifying
process through which major animal groups are adapted to local
circumstances through the elaboration of different species. Such
adaptation is not, however, the primary cuase of transformation from
group to group up the series. Consequently, in contrast to
Darwin's later theory, the primary evolution of life is not
through local adaptation.
5. Major transformation between lesser groups may, however, occur
through the action of the use and disuse of structures. For example,
the transformation of primates into humans presumably has occurred by
means of this adaptive process accompanied by an internal power of the
will.



The complex arrangement and ordering of groups envisioned by Lamarck
was a branching image of group development illustrated by the
following diagram added to his *Zoological Philosophy*.
Possibly responding to the analyses by his younger colleague Georges
Cuvier directed at the concept of linear relationships of groups (see
below), Lamarck admitted a more complex branching pattern of group
relations, with some showing independent lineages and even different
points of origin:



![a diagram: link to extended description below](lamarck-tableau-2-crop.jpg)

Figure 1: Lamarck Diagram from
"Additions" to the *Philosophie zoologique*, first
edition (1809), (page 463). [An
 extended description of figure 1
 is in the supplement.] 




This issue was not, however, developed in any theoretical elaboration
by Lamarck himself. The complexity of these issues in the subsequent
interpretations of Lamarck by his successors is an area of active
research (Corsi, 2021, 2012; Jenkins 2019).


### 4.2 Paris Museum Debates: Cuvier vs. the Transformists



Within the confines of the Paris *Museum* *national
d'histoire naturelle*, parallel, if not immediately
continuous, developments of related issues bearing on species
transformism were made by Lamarck's younger colleague and holder
of the chair of Mammals and Birds, the comparative anatomist Etienne
Geoffroy St. Hilaire (1772-1844). Less concerned with the issue
of species transformism than with the implications of comparative
anatomy and comparative embryology for the relations of forms,
Geoffroy St. Hilaire explored the anatomical "unity of
type"--the remarkable resemblance of anatomical structure
between organisms revealed by comparative anatomy. Pursuing this issue
in his own *Museum* lectures and in several papers,
Geoffroy St. Hilaire proceeded to work out the implications of the
inner anatomical similarities of vertebrates. Based upon two main
principles, the "principle of connection" and the
"law of balance", Geoffroy St. Hilaire drew attention to
the implications of comparative anatomy for the unity of the animal
kingdom.



By 1823, Geoffroy St. Hilaire had extended his theory of the
"unity of type" to the claim that even the invertebrates
shared a common plan with the vertebrates, and by 1825 he had embraced
a limited version of transformism with assertions that the unity of
type also revealed the relationships between ancient and contemporary
forms (Corsi 2011; Le Guyader 1998 [2004]: chp. 4]). This led him into
direct opposition to the claims of his one- time friend and colleague,
Georges Cuvier, holder of the *Museum* Chair of
Comparative Anatomy. who had argued in his *Lectures on Comparative
Anatomy* (1800-1805) that animal form involved a law-like
coordination between form and function for teleological purposes,
known as the "law of the correlation of parts." In his
*Regne animale* of 1817, this principle was extended to
the claim that comparative anatomy revealed a formal distinction of
four distinct and autonomous body plans
(*embranchments*)--Radiarians, Mollusca, Articulata, and
Vertebrata--that may display some unity of type within these
*embranchments*, but which precluded any theory of continuity
between these major plans. 



This anatomical argument was to constitute the mainstay of
Cuvier's opposition to transformism, and it served as a powerful
source of opposition to transformism into the Darwinian era and even
beyond. On the basis of these arguments, Cuvier also concluded that
comparative anatomy revealed genuine *extinctions* of species
in the past. First proposed in his paper on the species of elephants
in 1795, and then extended more broadly to vertebrate paleontology
generally in such works as his *Investigations on the Fossil Bones
of Quadrupeds* (1812), *Investigations on Fossil Bones*
(1821-1823), and in his *Discourse on the Revolutions of the
Surface of the Earth* (1822), Cuvier claimed that constraints of
organization and the systemic relations of anatomical structures meant
that species could not simply transform into others as claimed by
Lamarck and Geoffroy. As he developed its implications, it was
expanded into a theory of specific faunal and floral ages separated by
dramatic events--*Revolutions,* later termed by
others "catastrophes"--that led to massive
extinctions that required replacements of species by some cause that
was not specified. The issue of the "origin" of species in
the early nineteenth century was a direct consequence of these
Cuvierian extinctions.



The opposition between Cuvierian organicism and the Lamarck-Geoffroy
advocacies of transformism, centered on the claimed implications of
the "unity of type." This underlay the "great
debate" that broke out in French life science in the late 1820s
between Geoffroy St. Hilaire and Cuvier and their respective disciples
(Corsi 2012; Appel 1987). This debate also forms one of the historic
encounters between differing conceptions of biology that affected many
aspects of nineteenth-century life science. It drew division lines
within French, and even British, biology over the relation of
organisms to history, and it directly engaged the possibility of
species change. It also raised the issue of species origins. This
debate also served to focus issues within French life science in a way
that significantly affected the later negative French reception of
Darwin's work. This debate eventually was to involve issues of
paleontology, comparative anatomy, transformism of species, and the
relation of form to function. It also extended to issues of political
alliance and ideological commitments of numerous individuals in
Restoration France (Corsi 2011, 2012).



Cuvier's arguments, reinforced by the authority he carried in
French comparative anatomy and science generally, coupled with his
political influence during the Napoleonic and Restoraation periods,
resulted in the dominance of his positions within the Paris
*Academie des sciences*. Nonetheless, the tradition of
Geoffroy St. Hilaire remained a strong current within the
*Museum*. It was continued by such individuals as
Antoine Etienne Serres (1786-1868), whose arguments for a
historical sequence of forms, backed by embryological evidence, were
canonized in morphological circles as the Meckel-Serres law of
recapitulation (Corsi 2012; Gould 1977: chp. 3). Outside official
Academic French science, Geoffroy Saint Hilaire's theories had
broad appeal to those who saw the relevance of developmental
embryology for issues of group relationship, an issue that Cuvier, as
a moderate preformationist, had ignored. Present interest in the
relationship between evolution and developmental
biology--commonly termed "evo- devo"-- has
stimulated new attention to Geoffroy St. Hilaire's views (Le
Guyader 1998 [2004]).


### 4.3 Transformism in Britain 1830-1859



Discussions of transformism in the British Isles in the pre-Darwinian
period were influenced particularly by the French reflections and the
French debates taking place at the *Museum.* Following
the cessation of the Napoleonic Wars in 1814-15, extensive new
contacts developed between French and British scientists, particularly
through Edinburgh (Corsi 2021, Jenkins 2011). In addition to French
connections, there were also important personal contacts between
German and British scientists that also included the introduction of
German progressive developmentalism and transcendental anatomy in the
early decades of the nineteenth century both through Edinburgh, and
also directly into London scientific circles. The recognition of these
new introductions of French and German science and intellectual
traditions into the British Isles, particularly moving through medical
contexts, has supplied a new framework for understanding the
reflections on species change in Britain in the period before the
advent of Darwin's work (Rupke 2009; R. J. Richards 2002; Sloan,
2003, 1992b; Desmond 1989).



The Edinburgh comparative anatomist, Robert Edmond Grant (1793-
1874), played an important role in introducing the French discussions
into the British Isles. He would also serve as Charles Darwin's
first mentor in science when Darwin was a young medical student at the
University of Edinburgh (1825-27). Grant was directly engaged
with the issues being debated at the time between Geoffroy St.
Hilaire, Cuvier and Lamarck, and he advocated a variant of a
Lamarckian-Geoffroyean transformism in his writings, themes expounded
in his lectures on comparative anatomy at the new University College,
London where he became the first professor of comparative anatomy in
1827 (Desmond 1989). In addition to Grant, several other naturalists
in Edinburgh brought French discussions into the British context
(Corsi 2021, Jenkins 2011).


#### 4.3.1 The Lyellian Critique of Lamarckism



These French-inspired discussions of transformism entering mainly
through Edinburgh were subjected to a powerful critique by the Scots
lawyer turned geologist, Charles Lyell (1797-1875). In a
discussion that occupied seventeen of eighteen chapters (282 pages) of
the second volume (1832) of his landmark three-volume *Principles
of Geology* (1830-33), Lyell subjected Lamarckian theory to
a multi-level critique that was to influence much of the subsequent
opposition to transformism in British circles, and posed a wide range
of issues that Charles Darwin had to overcome subsequently. 



Opening with five chapters that analyzed Lamarck's assumptions
about species instability and summarizing his causal explanations of
both the serial ascent of life and the plasticity of form and function
under the influence of internal causes, Lyell developed a withering
attack on Lamarckism. In this discussion he questioned the empirical
evidence for species transformism, both in terms of evidence from
natural species, and also the warrant that could be drawn from changes
that have been produced in domestic animals and plants by human
activity. Moving beyond this, he then questioned the evidence for
connections of living forms across biogeographical regions, and the
evidence for substantial change in historical migrations between zones
of habitation. 



A second level of critique concerned the evidence assumed by Lamarck
(and Geoffroy) for historical progressionism in the forms of life,
with oldest rocks showing simplest forms, and subsequent geological
formations (Secondary, Tertiary) showing the appearance of higher and
more complex forms eventually resulting in the mammals. This theme of
geological progress, embraced not only by transformists, but also by
British disciples of Cuvier, was attacked by Lyell with an argument
that would later be used by Darwin to different ends--the
imperfection of the geological record. In Lyell's view, the
accidents of fossilization undercut any inference from the fossil
record concerning an assumption of the historical development of life.
Against speculations of Lamarck and others concerning evidence for a
progression from simpler forms to those now existing, Lyell replies
with reference to plant evidence that,



> 
> 
> Those naturalists, therefore, who infer that the ancient flora of the
> globe was, at certain periods, less varied than now, merely because
> they have as yet discovered only a few hundred fossil species of a
> particular epoch, while they can enumerate more than fifty thousand
> living ones, are reasoning on a false basis...: (Lyell 1832
> [1991], 245; see also p. 20).
> 
> 
> 



In examining these issues, Lyell concludes that empirical evidence
only supports a claim of limited transformations of a varietal level
that remains within natural species boundaries. In Lyell's
conclusion, there was no empirical support for the transfomism of
species.


#### 4.3.2: German Philosophy of Nature and British Developmentalism



In addition to French-inspired developments of transformism that Lyell
focused on in his critique of Lamarck, a lesser-studied introduction
of German philosophy of nature and German reflections on anatomical
resemblance formed a different current of reflection with significant
consequences for the mid-nineteenth century discussions of the
transformist question in the British Isles. The cessation of the
Napoleonic hostilities was accompanied by the introduction into
British discussions of German scientific thought along with
expositions of the systematic philosophies of Kant, Fichte, Hegel and
Schelling (Sloan 2003). With relevance to species transformism,
Schelling-inspired themes in the philosophy of nature were expounded
in the Hunterian Lectures in Comparative Anatomy at the Royal College
of Surgeons in London, delivered by the British surgeon Joseph Henry
Green (1791-1863). Green utilized dimensions of
Schelling's *Naturphilosophie* to develop in his lectures
between 1820-27 a dynamic theory of group relations which
synthesized the work of Lamarck, Cuvier, and the University of
Gottingen medical theorist Johann Blumenbach (1752-1840
(Sloan, 1992b, 2007), relations which he even depicted in tree-like
branchings of relationship that went beyond those of Lamarck.



![a diagram: link to extended description below](Green27-scale.jpg)

Figure 2: Joseph Henry Green's
diagram of the relations of the invertebrate and vertebrate groups in
1827 as represented in the notes of Richard Owen. [An
 extended description of figure 2
 is in the supplement.] 




These themes would be continued in the major series of lectures
delivered by Green's protege at the College of
Surgeons, the comparative anatomist, Richard Owen (1804-92), who
was named to the prestigious Hunterian Chair in Comparative Anatomy
1837 and remained in that position until 1856 (Rupke 1994, 1993; Sloan
1992b) 



Owen's widely-attended London lectures delivered between 1837
and 1856 brought many of the issues of comparative anatomy,
classication, fossil evidence, and embryology to bear on the questions
of species relationship and change. In these lectures, presented
against the backdrop of the massive anatomical collections of the
Hunterian Museum in London, Owen developed a reinterpretation of the
significance of the Cuvier-Geoffroy dispute and developed its
implications for issues surrounding the historical development of the
vertebrates as represented in this diagram he made in 1837. 



![a diagram: link to extended description below](Owen27-scale.jpg)

Figure 3: Richard Owen's
representation of the relation of the main animal groups in February,
1837. [An
 extended description of figure 3
 is in the supplement.] 




As a solution to the Cuvier-Geoffroy issues, Owen subsequently
developed in his Hunterian lectures in 1845 the theory of the
archetypal vertebrate that connected the anatomical relations of all
the vertebrates, a theme he then elaborated in an important set of
publications in 1847 and 1849 (Owen, 1847, 1849 [2007]). Employing
aspects of William Whewell's philosophy of science to develop
these arguments, Owen expounded the theory of the unity of type in
relation to the Cuvierian analysis of the relation of form and
function. In his argument, the archetype, functioning both as a
transcendental ideal form and also as an immanent law working in the
material history of life, explained the progression and
differentiation of the vertebrates in historical time ((Sloan 2003; R.
J. Richards 2002: chp. 14; Rupke 1993). 



![line drawing: link to extended description below](archetype.jpg)

Figure 4: Richard Owen's depiction
of the Archetypal Vertebrate, composed of a series of ideal vertebrae
as in his *On the Nature of the Limbs* (1849),
"Appendix". [An
 extended description of figure 4
 is in the supplement.] 




By means of this theory, Owen claimed he could coherently explain both
the deep resemblance of forms in their internal anatomy--the
theme emphasized by Geoffroy St. Hilaire--, and also the close
fitting of structure and function to the organism's
"conditions of existence", the insight emphasized by
Cuvier.



To distinguish these two meanings of relationship, Owen introduced
into the literature in 1843 a crucial distinction between resemblances
of "homology", meaning the presence of the
"same" parts in every variety of form and
function--Geoffroyean relationships--and those of
"analogy", denoting solely the similarity of parts in
their functional adaptations--Cuvierian relationships. Developing
this concept of homology in relation to his theory of the archetype,
Owen claimed he could at last give a coherent meaning to the concept
of "sameness" in anatomical relationships--the
warrant for speaking, for example, of a "femur" in a bird
and a mammal as the "same" bone in different forms and
functions. Furthermore, as Owen developed this theory in relation to
his work on the fossil record, the theory of the archetype, conceived
also as an immanent law working in history, led Owen to embrace a
concept of branching and diversifying relations of forms in history as
divergences from this ideal archetypal form over time
 (fig. 3
 above). Owen thus broke with the linear historical progressionism
from simple to complex assumed in several transformist theories. 



On the other hand, Owen's model cannot be considered to
represent genuine species transformism--species do not change
historically one into another and the archetype exists as a
quasi-Newtonian ideal "law" governing development in time
rather than designating an actual historical form that materially has
given rise to successive forms displaying homologous relationships.
Nonetheless, his integration of comparative anatomy, paleontology, and
even embryology into this framework, set out a sophisticated model of
relationship that was later reinterpreted by Darwin from the viewpoint
of his theory of material derivation from common historical
ancestors.


#### 4.3.3 Popular Transformism in Britain, 1844-1859



On a more popular level, species transformism was broadly popularized
in pre-Darwinian Anglophone discussions by the appearance in 1844 of
the grand evolutionary cosmology put forth anonymously by the Scottish
publisher Robert Chambers (1802-71) in his immensely popular
*Vestiges of the Natural History of Creation* (Chambers
1844[1994]), a work which in many respects prepared Victorian society
in England, as well as pre-Civil War America, for Darwin's more
restricted theory of 1859 (Secord 2000; MacPherson, 2015). More
similar to Buffon's *Epochs of Nature* than to the
writings of Lamarck, Chambers proposed an evolutionary schema that
began with the nebular beginnings of the cosmos, the geological
history of the earth interpreted as a progression of ages, accompanied
by a historical progression of life from simple to complex, the cosmos
moved in a teleological direction up to humanity, with a broad
evolution of species up the chain of being. In this grand schema he
incorporated insights from French zoology and geological
progressionism, ignoring the refutations of this by Lyell, with all of
this working under the actions of one great unifying natural law that
demonstrated a great divine design of nature. This vision was further
popularized by its incorporation into Alfred Lord Tennyson's
epic poem *In Memoriam* (1850). In spite of the popularity of
Chamber's work, which went through eleven editions by the end of
the nineteenth century and sold more copies than Darwin's
*Origin of Species*, the British scientific community was
essentially unanimous in its rejection of Chamber's
speculations, with Lyellian and Cuvierian critiques forming a solid
scientific basis for these arguments. In many ways this opposition to
the *Vestiges* by leading members of the Victorian scientific
establishment formed one primary source of professional resistance to
the later Darwinian theory (see entry on Darwin: From the *Origin
of Species* to the *Descent of Man*, Section 3).



A more philosophically influential developmental evolutionism was also
advocated in pre-Darwinian England by the British railway engineer and
public intellectual, Herbert Spencer (1820-1903)
 (Herbert Spencer).
 Inspired both by the expositions of Lamarckianism by Charles Lyell in
the second volume of his *Principles of Geology*
(1830-33), by the writings of Karl Ernst von Baer on
embryological development, and also by Richard Owen's Hunterian
Lectures on the osteology of the vertebrate skeleton, which Spencer
attended in 1851 (Rupke 1994: 206), Spencer entered the British
discussions of transformism in 1852 with his endorsement of the
"development hypothesis" (Spencer 1852). This initiated
his broad reflections on the law-governed evolution of society and
humanity, developed in detail in such works as *First
Principles*, published in 1862 (Haines 1988). Prior to the use of
the term by Darwin, Spencer spoke of the "evolution" of
life and the cosmos from material beginnings, with species changing as
a result of the operation of natural forces. It was also from Spencer
that Darwin borrowed the designator "survival of the
fittest" as a synonym for his own "natural
selection" in the fifth edition of the *Origin of
Species* in 1869. Although Spencer's *First
Principles* appeared after the publication of Darwin's
*Origin*, Spencer's transformism was developed generally
independently of Darwin's work and shows closest affinity with
the reflections of Lamarck, Chambers, and the historical
developmentalism of Owen.



Spencer, rather than Darwin, has often been seen as the primary
theoretician of "social" Darwinism in the late nineteenth
and early twentieth centuries (Hofstadter 1944 [1955]; see also the
entry on Herbert Spencer). Spencer's world-wide influence even
made his works a vehicle by which Darwinism was first introduced into
non-Western discussions (Jin 2019, 2020; Lightman (ed.) 2016; Elshakry
2013; Pusey 1983). This unusual juxtapositioning of Spencer and Darwin
is explored in the entry
 Darwin: From the *Origin of Species* to the *Descent of Man*
 (Section 3.1).


## 5. Summary and Conclusion



The long historical scenario summarized in the present entry has
sought to display the complexity of transformism in biology in the
period as it developed independently of the advent of Darwinism. This
history reveals several lines of non-Darwinian transformism that were
current and under discussion in the natural historical sciences which
were converging on larger explanatory theories of the history of life.
It also lends plausibility to the claim of historian Peter Bowler that
without Darwin, life and earth science would still likely have come to
a "science that we could still recognize, although its
components would seem to have different implications, thanks to having
been assembled in a more natural sequence of discovery" (Bowler,
2013, p. 279). It was against this complex background that Darwin
would develop his own theory on the origin and diversification of
forms with emphasis on the principle of natural selection. He would,
however, draw in many ways on these pre-existing discussions in
French, British and even German sources, and reinterpret these issues
against the framework of criticisms that had emerged against
transformism. Further exploration of this will be made in the entry
Darwin: From the *Origin of Species* to the *Descent of
Man*.