## 1. Life, Works and Influence



Bernardino Telesio was born at Cosenza in Calabria in 1509 as the son
of a noble and quite wealthy family. Having been educated by his uncle
Antonio Telesio, a humanist of note, he studied in Milan, Rome and the
famous university of Padua, which he left in 1535. There is no
evidence that Telesio gained a doctorate. Instead of undertaking a
university career, he spent several years in a Benedictine monastery
(1535-44) without taking oaths. Later he lived in the Neapolitan
home of Alfonso III Carafa, Duke of Nocera. In 1553 he married and
settled in Cosenza, becoming the dominant figure of the Accademia
Cosentina, which came to focus on natural philosophy under his
tutelage. Telesio never held a salaried position. After the death of
his wife in 1561, which marked the beginning of his financial
difficulties, he seems to have spent some time in Rome under the
patronage of Pope Pius IV. He rejected the Archbishopric of Cosenza
offered by Pius IV in 1565, leaving this position to his brother. From
1576 on he was moving between Cosenza and Naples; in Naples he lived
with the son and heir of Alfonso Carafa, Ferrante, to whom he
dedicated the final version of his *De rerum natura*. He died
in his hometown in 1588.



Telesio dedicated his whole life to establishing a new kind of natural
philosophy, which can be described as an early defense of naturalism
and empiricism bound together with a rigorous criticism of
Aristotelian natural philosophy and Galenic physiology. Telesio blamed
both Aristotle and Galen for relying on elaborate reasoning rather
than sense perception and empirical research. His fervent attacks
against the greatest authorities of the Western philosophical and
medical traditions led Francis Bacon to speak of him as "the
first of the moderns" (*Opera omnia* vol. III, 1963, p.
114). He was perhaps the most strident critic of metaphysics in late
Renaissance times. It was obviously due to his excellent relationships
with popes and clerics that he was not persecuted and was able during
his own lifetime to publish his rather heterodox writings, which went
on the index shortly after his death. His principal work is the
aforementioned *De rerum natura iuxta propria principia*
("On the Nature of Things according to their Own
Principles"), which in the last augmented edition of the
author's hand appeared in Naples in 1586. The *De rerum natura*
is a huge treatise in nine books which deals with cosmology, biology,
sense perception, reason and ethics. Another treatise of major
importance is *Quod animal universum ab unica animae substantia
gubernatur. Contra Galenum*, in which Telesio critizised central
conceptions of Galenic physiology and psychology. This work was never
printed, but circulated in manuscript copies (De Franco, 1981, p.
XXII). Smaller treatises deal with a variety of themes such as
colours, dreams, geology and meteorology, some of which were published
in Rome in 1565 (*De iis quae in aere fiunt et de
terremotibus*; *De colorum generatione*; *De mari*).
Telesio's philosophy was disseminated by friends and students such as
Tommaso Campanella, whose writings contain long paraphrases of
Telesian ideas; by Sertorio Quattromani, Telesio's successor as head
of the Accademia Cosentina, who published a synthesis of his
predecessor's philosophy in 1589; and by Antonio Persio, who gave
lessons on Telesio's thought in Venice and published a collection of
smaller works, the *Varii de naturalibus rebus libelli*, in
1590. Giordano Bruno speaks of the "giudiciosissimo
Telesio" in the third dialog of *De la causa*, whilst
Francis Bacon based his own speculative philosophy of nature on a
blend of Telesian and Paracelsian conceptions (Giachetti Assenza 1980;
Rees 1977; 1984). Thomas Hobbes followed Telesio in the rejection of
species (Schuhmann 1990; Leijenhorst 1998, p. 116ff.) The physiology
of Rene Descartes in *De homine* shows close
similarities to Telesio's physiological theories as they are presented
in *De natura rerum* (Hatfield 1992). Telesio also had some
influence on Gassendi and on libertine thinkers (Bianchi 1992).


## 2. Cosmology



Telesio's vision of the genesis of nature is simple to the point of
being archaic, yet at the same time astonishingly modern in the sense
that he seems to have been one of the very first defenders of a theory
of natural evolution without metaphysical or theological
presuppositions. According to his *De rerum natura*, the only
things which must be presupposed are passive matter and active force,
the latter of which Telesio thought of as twofold, heat and cold.
These principles were meant to replace the Aristotelian metaphysical
principles of matter and form. In order to explain how all natural
beings came into existence by these opposing forces, Telesio
presumed that in the beginning God had created two primary globes, the
sun and the earth, the sun being the seat of heat, the earth that of
coldness, and that He had separated them with such a distance in space
that they could not extinguish each other (DRN book I, ch. IV). All
natural things result from the battle of these antagonistic forces for
the possession of matter. The main region of that creative battle is
the surface of the earth, where they create metals, stones and animate
beings. The primary activity of warmth is to move fast and to dilate
and rarefy matter, whereas that of cold is to hinder movement and to
condense matter. Things differ according to the amount of heat or cold
they possess (and therefore according to their density and derivative
qualities such as velocity and colour). The quantity of matter is not
changed through the action of these forces upon it. The role of heat,
cold and matter as 'natural principles' had been
highlighted before by Girolamo Fracastoro in the first version of the
*Homocentrica* and in the dialogue *Fracastorius sive De
anima* (Lerner 1992), as well as by Girolamo Cardano in his
*Liber unicus de natura.*



Telesio's cosmology puts an end to metaphysical explanations. Telesio
thought space to be absolute (DRN book I, ch. XXV-XXVIII), thus
abolishing the Aristotelian notion of a bipartite cosmos divided into
a sublunary world, in which generation and corruption take place, and
a supralunary sphere with eternal regular movements. The existence of
vacuum within space is admitted, but things are said to have a natural
inclination to avoid empty space. In the cosmological chapters of book
IV Telesio critizised the Aristotelian explanation of the movement of
the cosmos by a transcendent telos, the God of Aristotle's
metaphysics: the sky doesn't move because of a desire for a being more
perfect than itself, but because it is its own nature to move and thus
to sustain its own life (DRN book IV, ch. XXIV; Aristotle,
*Metaph*. XII, ch. 6-7). Likewise, he rejected the idea
that the motions of the subordinate spheres were caused by unmoved
movers, the pure intelligences of the Aristotelian and Christian
traditions, an assumption which he reprimanded to be obscure and
incomprehensible even via imagination (Bondi 1018).



The things of nature are not created, governed and sustained by divine
providence. In Telesio's philosophy, there is no such thing as a
transcendent mind or idea. All things act solely according to their
own nature, starting from the primary forces of cold and heat. The
Epicurean chance is enclosed in Telesio's Stoic-influenced philosophy
of nature (Kessler 1992): everything can produce everything, an idea
which was soon to be sharply rejected by Francesco Patrizi da Chierso,
one of the most important contemporary readers of Telesio
("Obiectiones", in the appendix of Telesio's *Varii
libelli*, p. 467 f.). In order to sustain themselves, these
primary forces and all beings which arise through their antagonistic
interaction must be able to sense themselves as well as the opposite
force, that is, they must sense what is convenient and what is
inconvenient or damaging for their survival and well-being. Sensation,
therefore, is not the property of embodied souls. Telesio's philosophy
can thus be described as a pansensism in the sense that all beings,
animate or inanimate, are said to have the power of sensation.


## 3. Psychology



With regard to psychology, Telesio took a materialist standpoint.
According to his general rejection of the metaphysical (and therefore
inappropriate) principles of matter and form, he rejected Aristotle's
definition of the soul as *forma corporis*, i.e. as form and
entelechy of an organic body (Aristotle, *De anima* II,1).
According to Telesio, the soul is a separate being, but not in the
sense of the Platonists, who define it as an immortal essence acting
as the governor and mover of the body during its embodied life.
Telesio held the soul to be a specific part of the body, defining it
as the *spiritus* coursing through the nervous system and
having its main seat in the brain. The *spiritus* which
overtakes the role of the *anima* of the philosophical
tradition is produced by the white 'semen'. Telesio calls
it the *spiritus e semine eductus*. He maintains in DRN book V,
ch. I:



"This [separate substance] will therefore be the
*spiritus*, which took its origin from the semen, as we will
explain elsewhere (and it is to be found in all things made from
semen, namely those which are white and bloodless, with the exception
of the bones and similar things); and only the spirit is what
perceives in the animal, and moves sometimes with the whole body,
sometimes with single parts thereof, and solely governs the whole
animal. That is to say, it performs those actions which, according to
the concurring opinion of all, are typical of the soul." (Vol.
II, p. 208).



To ascribe psychic functions to a specific part of the body implies a
rejection of the difference between organic and inorganic life, which
dichotomy was central to the Aristotelian, Platonic and Christian
traditions. According to Telesio, there is a quantitative and not a
qualitative difference here, which consists in the higher degree of
complexity and the higher degree of warmth that some physical bodies
possess. Whereas metals or stones are homogenous bodies, organic
bodies consist of heterogeneous parts, including the bodily (though
invisible) spirit in the nerves and brain (DRN book V, ch. II). And
just as there is no metaphysical difference between living and
non-living bodies, there also does not exist a qualitative difference
between animals and humans--in both, it is the same spirit which
coordinates the functions and operations of the different bodily
parts. In DRN book V, ch. III Telesio states:



> 
> ...and when it has been proved that in animals the spirit
> produced from the semen is the substance of their soul, then one
> cannot doubt that the same exists in humans, albeit in a much more
> noble form, and it is surely not of a very different nature and does
> not possess highly different capabilities. We see that humans are
> formed by the same things as the other animals, and that they possess
> the same abilities and even the same organs for feeding and
> reproduction, and that they produce a very similar semen and eject it
> in the same way and with the same pleasure and from a very similar
> part and become tired after ejaculation, and that the same things are
> being formed out of the semen in both cases, namely the same nervous
> and membranous systems. And it is only [the spirit] which in all
> animate beings is perceiving and moving in the same way and according
> to the same dispositions. (Vol II, p. 216).
> 



In order to explain how animate beings perform different functions and
operations, traditional psychological as well as physiological
theories referred to a threefold soul. Whereas Aristotle in *De
anima* had distinguished between the *anima vegetativa*,
*anima sensitiva* and *anima cogitativa* (which
distinction also corresponds to that of plants, animals and humans
with their specific faculties), Plato had established three parts of
the soul (*Republic* 434d-443e), which in the *Timaios*
(69aff.) he had associated with different organs, namely the rational
part of the soul (*logistikon*) to the brain, the spirited
(*thumoeides*) to the heart and the desirous or lower passions
(*epithumetikon*) to the liver. In this
tripartition he was followed by the Stoic physician Galen (*De
placitis Hippocratis et Platonis* VII, I and III), who added a
threefold spirit--the *spiritus naturalis* being produced
in the liver, the *spiritus vitalis* refined in the blood and
the *spiritus animalis* distilled in the brain. Whereas the
Aristotelian psychology was combatted in the *De rerum natura*,
Telesio dedicated a whole treatise to the criticism of Galen, the
*Quod animal universum ab unica animae substantia gubernatur.
Contra Galenum*. According to Telesio, the functioning of an
organic body cannot be explained by presupposing a plurality of
rulers. In asserting the unity of the soul (i.e. spirit), Telesio
followed the medical theorist Giovanni Argenterio (1513-1572),
who defended the unity of the spirit against the Aristotelian and
medical traditions.



Telesio combined the medical theory of spirit with a basically Stoic
notion, that of the *hegemonikon*, according to which the
spirit in the brain is responsible for all the states and operations
traditionally ascribed to the tripartite soul: "the animal
... is governed by one substance residing in the brain"
(*Quod animal universum* ch. XXV; Var. lib. p. 254). Whereas in
*Quod animal universum* he went on to explain the affects in
terms of physiology, in *De rerum natura* he added a theory of
sense perception and a theory of knowledge on physical grounds.


## 4. Theory of sense perception



Telesio rejected the traditional concept of sense organs, replacing it
with a mechanistic explanation of sense perception (DRN books
V-VII). In his opinion, to speak of sense organs is
inappropriate, as the so-called sense organs are nothing else than
"parts of the body which are either more subtle or soft than
others, or perforated and open. One should not believe in the
slightest that they are made thus in order to offer some capacity or
support of perceiving to the sensitive soul (which seems to be the
duty of organs), but in order to provide an easy and open entry to the
forces of external things and to those things themselves." (DRN
book I, ch.VI; vol. I, p. 68). What is perceived are not the forms or
*species* of things as the Aristotelians believed, but impulses
of light and air (DRN book V, ch. VIII; vol. II, 254; for the
rejection of *species* see DRN book VII, ch. XXX-XXXIII
against the Aristotelian and ch. XVIII-XXIX against the Galenic
theory; Telesio's rejection of *species* was taken up by
Hobbes, *Leviathan* book I, ch. I "De sensu"). As
the sense of touch provides the most narrow contact between outer
object and sensing spirit, it assumes the role of the primary sense,
which was traditionally identified with the sense of vision (DRN book
VII, ch. IX, vol. III, p. 34.) The *informatio* theory being
rejected, Telesio comes close to a neuronal explanation of sense
perception, which is a mechanical process arising from the transfer of
tactile impressions through the nerves to the brain. It is the spirit
residing in the brain which experiences nervous dilatations and
contractions, and which judges these sensations according to the basic
scheme of pleasure and pain, giving out corresponding reactions like
moving towards something or avoiding contact (DRN book VII ch.
II-V). Strictly speaking, sense perception is a sensation of
sensing (*sensus sensus*) which takes place in the brain:
"Sense perception can only be the perception of the activities
of things and impulses in the air, and can only consist of the
perception of [the spirit's] own passions, transformations and
movements, particularly the latter. Indeed, the spirit perceives them
because he perceives that it is affected by them, that it is being
changed and moved." (Vol. III, p. 6)



In his explanation of sense perception Telesio comes close to the
Democritan theory which he combines with the basic Stoic notion of
*conservatio sui*, a key term in Telesio's philosophy. Pleasure
is identified with the sensation of self-preservation, pain is the
sensation of destruction (DRN book VII, ch. III; vol. III, p. 10). In
this, as well as in his theory of knowledge, Telesio seems to follow
Girolamo Fracastoro's explanation of sense perception and
understanding given in the closing chapters of *De sympathia et
antipathia rerum* and in the epistemological treatise *Turrius
sive de intellectione*.


## 5. Theory of knowledge



For Telesio, the *conservatio sui* is the foundation from which
all sensitive and cognitive functions arise. Defending an empirical
approach in epistemology, Telesio tried to annul the traditional
distinction between sense perception and reason, and he denied that
there exists something like a purely mental sphere and a corresponding
intellect which Aristotle in *De anima* III had called
*nous*. Understanding is a process which requires sense
perception and memory. According to Telesio, our memory is not visual.
What we remember are movements which our spirit has experienced and
given out when being in contact with external forces. If now the
spirit undergoes a similar experience, for example the pain of getting
burned, it will ascribe this perception to a similar or identical
cause and call it 'fire' (DRN book VIII, ch. 1; vol. III,
p. 160). The ability of making rational conclusions
(*ratiocinari*) consists in comparing new expierences to old
ones and in supplementing hidden or unknown aspects when refering them
to former experiences. Telesio even suggests replacing the term
*intelligere* with *existimari* and *commemorari*
(DRN book VIII, ch. III; vol. III, p. 164f.). Intellectual
understanding therefore does not mean to reach a realm of necessity
and eternity, not even in mathematics, which according to Telesio
arises from sensual experience and is a science of less dignity than
the observation-based natural philosophy (DRN book VIII, ch. IV; vol.
III, p. 176f.).


## 6. Ethics



The ethics exposed in the 9th book of *De rerum
natura* is strictly naturalist. The only objective which Telesio
ascribes to the spirit is self-preservation and self-improvement, the
former lying in its ability to react suitably to influences from the
external world, the latter in its capability of finding means to
improve its state of being. This comes about through theoretical
knowledge, specifically through natural philosophy and medicine (cf.
DRN book VIII, ch. XXI) and through learning to control one's own
emotions and desires. According to Telesio, we can voluntarily provoke
and suppress affections and their related actions (DRN book IX, ch. I;
vol. III, p. 332f.); what is more, we are able to master the degree to
which we desire and are affected (DRN book IX, ch. II; vol. III, p.
334). The principle of moral virtue is said to be a knowledge of what
is helpful and what is damaging for survival and well-being in human
society. All virtues and vices are reduced to self-conservation.


## 7. Science and Religion



Whereas medieval and Renaissance authors often seemed to rely on the
double-truth theory in order to maintain the freedom of scientific
research and teaching, Telesio maintained a purely scientific
approach. But he did not deny the existence of God and of the human
soul. Telesio's God is not the God who acts in nature and history,
though he did not deny the possibility of miracles (DRN book IV, ch.
XXV; vol. I, p. 176). The God Telesio seems to imagine can be compared
to a mechanic. Just as the best mechanic creates an artefact which
will work without interruption and default, so the power of the
almighty divine artist is represented in a cosmos which is able to
generate and to sustain itself without ever running the danger of
corruption (see DRN book I, ch. X).



Besides the natural soul or spirit Telesio accepted the existence of
an immortal soul superimposed by God (DRN book V, ch. II-III).
But in his theory of psychology and ethics the soul does not play any
significant role, for which reason researchers have often held it to
be an addition designed to avoid conflicts with the Church. On the
other hand, there do exist certain modes of behavior which cannot be
explained in a purely naturalistic and materialistic way, such as the
human striving for eternity and the martyrs' denial of the highest
objective of self-preservation. But far from building a bridge to the
philosophical tradition, Telesio's definition of a second, divinely
superimposed soul as "forma corporis et praecipue
spiritus" deals a deathblow to Aristotle's teachings. According
to Telesio, the idea of an immortal soul was totally unknown to the
heathen Aristotle, who is severely criticized for confusing the
concept of a natural spirit with the religious idea of a soul (DRN
book V, ch. II-III):



> 
> And when we have reproved Aristotle and will continue to reprove him
> for having introduced the soul into the body as its peculiar form, we
> have not condemned him and we will not condemn him because he equated
> the soul created by God (a thing which one might suspect was
> completely unknown to him) with the form of humans, but rather
> because... he equated the soul which was generated from the semen and
> which is the only one which senses, causes movements and is (so to
> speak) something akin to the semen, with the form of the body. (Vol.
> II, p. 218f.)
> 



Nonetheless, the few pages which Telesio dedicated to the immortal
soul do not open a path to metaphysical or theological theories. In
science, Telesio adheres to a naturalistic worldview. It was Tommaso
Campanella who combined Telesian naturalism with a theory of the anima
creata and human mind which he based upon sceptical doubts. (Boenke
2005, Ernst 2014, Bondi 2018).