## 1. Life and works



Born into a noble Neapolitan family in 1535, Porta published his
*Magiae naturalis libri IIII* in 1558. The immediate success of this
book firmly established Porta's reputation as a learned magus
and professor of secrets in the European world. The book saw sixteen
Latin editions; six Italian, seven French and two Dutch versions
appeared by 1588 alone (Balbiani 2001), although in 1583 the book
ended up on the Madrid Index of Prohibited Books due to Porta's
naturalistic approach to witchcraft (Ernst 1990). A second version in
1589 was enlarged to twenty books. Due to severe difficulties with
ecclesiastical censorship (the Roman Holy Office had begun legal
proceedings against Porta in the early 1570s), he remained under
life-long surveillance by the inquisition (Valente 1999).



Porta's many difficulties with the inquisition--censors
disapproved of his works on divinatory arts such as physiognomonics,
the art of predicting character traits from the faces of
humans--were compounded by the distrust of more orthodox
intellectuals such as Jean Bodin (1529/30-1596), who would have
loved to see Porta burn at the stake for naturalizing the
Witches' Sabbath, because Porta--like Girolamo Cardano
(1501-1576)--had divulged a recipe for the infamous
witch's unguent (*Magia* 1558: lib.2, ch. 26; Ernst 1990; Balbiani
2001).



Early in his life, Porta apparently founded an academy of secrets
dedicated to the study of natural phenomena. Its members could only be
appointed if they had discovered a hitherto unknown segreto (Badaloni
1959/60). The meetings seem to have been held in Porta's
Neapolitan palace. This was by no means uncommon, for by the middle of
the sixteenth century there existed at least six such academies in
town (Eamon 2017). There also exists some intriguing archaeological
evidence for special subterranean meeting rooms under Porta's
villa in Vico Equense, then a village just outside Naples (Balbiani
2008). After 1558, Porta travelled widely, stopping in Apulia,
Calabria, Lombardy, Venice, and Paris. In Spain he seems to have
visited the court of Philip II, a renowned patron of alchemy who
sought miraculous medicines for himself and his family's
ailments.



The *Magia Naturalis* is, unsurprisingly, dedicated to this important
patron. Porta presented Philip II with another book on ciphers (*De
furtivis litterarum notis vulgo de ziferis libri IV* 1563), followed by
*L'arte del ricordare* (1566), a treatise on the art of memory (a Latin
version appeared in 1602 under the title *Ars reminsicendi*). In 1579
and during the following years, Porta was repeatedly invited to Rome
by Cardinal Luigi D'Este (1538-1586), ostensibly to pursue his
research into the secrets of nature, but perhaps more importantly to
enjoy some protection in his household during his trial before the
inquisition (Perfetti 2001). 1580 found Porta overseeing the
construction of a parabolic mirror in Venice, where he met Paolo Sarpi
(1552-1623) (Reeves 2008).



Having sold parts of his Neapolitan palazzo in the preceding year,
Porta returned to Naples in 1582 and began researching the
philosopher's stone at the behest of Cardinal D'Este. In the
following two years he published two treaties on agriculture (Pomarium
1583, Olivetum 1584) and his richly illustrated Humana physiognomia
(1584). In 1586 Porta was probably again summoned before the
Neapolitan Inquisition, perhaps together with Luigi Tansillo
(1510-1568), an influential poet (and a close acquaintance of
Giordano Bruno (1548-1600)). Porta was instructed to abstain
from publishing on divinatory and magical arts and write comedies
instead.



That same year Porta returned to Rome under the protection of Cardinal
D'Este, who died a couple of years later. In 1588 and back in Naples,
Porta published a physiognomony of plants (Phytognomonica) and a
translation of the first book of Ptolemy's Almagest. The
following year saw the publication of the second, much enlarged
edition of the *Magia naturalis* and the comedy *Olimpia*, which may have
been staged in the presence of viceroy Don Juan de Zuniga
(1551-1608). In 1590, Porta met Tommaso Campanella
(1568-1639); in the next year he published the tragicommedia
*Penelope*, followed in 1592 by the comedy *Fantesca* as well as *Villae*, a
treatise on agriculture.



The Venetian Inquisition prohibited the publication of the Italian
version of the Human Physiognomony. The ban was reinforced in 1593,
when *De refractione*, a treatise on optics, came out. In 1596
*Trappolaria*--another comedy--was printed. Now famous across
all Europe, in 1598 Porta dared to defy the inquisitional ban and
published *Della fisionomia del'huomo* under the pseudonym
Giovanni de Rosa. For the following three years Porta seems to have
kept a deliberately low profile; his tragicomedies *Fratelli rivali* and
*Cintia* came out only in 1601. Porta then had the Latin version of his
treatise on the art of memory printed, as well as *Penumaticorum libri*
tres (on the vacuum and how to lift up liquids) and *Curvilinearum
elementorum libri duo* (on mathematics), two treatises that reappeared
in enlarged versions as *I tre libri spiritali* (1606) and *Elementorum
curvilineorum libri tres* (1608). In 1603 Porta outlined a naturalized
form of divinatory astrology and physiognomics in the *Coelestis
physiognomonia*. Federico Cesi (1585-1630), a young Roman
nobleman with a passion for natural philosophy who founded the famous
Academia dei Lincei, visited Porta in 1604. Sorella was published in
the same year. Between 1606 and 1607 the comedies *Astrologo*, *Turca*,
*Carnbonaria* and *Moro* were published. The short treatise *De
distillationibus* (1608) became another of Porta's bestsellers,
but this success was overshadowed by the death of Gianvincenzo Porta,
his brother and collaborator. *De munitione*, a treatise on military
fortifications and on firearms, came out in 1608; in the following
year two comedies (*Furiosa* and *Chiappinaria*) were published. 1609 also
marked the beginning of Porta's dispute with Galileo Galilei
(1564-1642) (another famous member of the Academy of the Lynx)
over who had first invented the telescope. The Lincei reopened in
1610, due to the death of Cesi's father, who had disapproved of
Federico's scientific endeavours; Porta's discovery of the
telescope was acknowledged by the Academy, and he became director of
its Naples branch (which, however, never opened, Freedberg 2002). Even
so, Porta's role and influence on Cesi seems to have been
considerable (Torrini 2018). The Holy Office prohibited the
publication of Porta's treatise on palmistry, *De ea naturalis
physiognomoniae parte quae ad manuum lineas spectat*. In 1611 Porta
opened the academy of the Otiosi, an institution dedicated to letters
and to science; some of his plays may have been staged there. Porta
seems to have worked simultaneously on the telescope and the
philosopher's stone. These endeavours resulted in the draft for
his last and largely unfinished work on (more or less) natural magic,
the *Criptologia* and the *Thaumatologia*, which was to be dedicated to
Rudolf II. This text testifies to Porta's systematic interest in
demonology and Neoplatonic magic (Maggi 2015). Needless to say, it was
never to obtain an imprimatur by the ecclesiastical authorities. The
tragedy *Gregorio* (1611) was published, as well as the comedy
*Tabernaria* (1612) the following year; in 1613 Porta was honored by the
Lincei with a medal cast by Francesco Stelluti (1577-1653).
Another comedy, *Fratelli simili*, and the tragedy *Ulisse* were published
in 1614. In February 1615 Porta died in the house of his daughter
Cinzia: there are no records of Porta's wife, whose name is
unknown (for Porta's biography in general, see Clubb 1964, Romei
1989; Piccari 2007, Eamon 2017, Verardi 2018).


## 2. Works on Magic



A large part of Porta's philosophical speculation is contained
in the two versions of his *Magia naturalis* (1558, 1589), crystallized
in the persona of the natural magus. Porta seeks to avoid all
religious topics, as well as even the remotest hint of ceremonial
magic; other than in the third book of Heinrich Cornelius Agrippa of
Nettesheim's (1486-1535) *De occulta Philosophia*, for
instance, there are no instructions for prayers, fasting, or
invocations (Klaassen 2013). Porta's magic is thus less a way to
improve one's own mind or to communicate with divine forces, and
more a means to manipulate objects and human beings. Porta developed
this secular approach to magic in the face of ecclesiastical
prosecution, for it seems that he was condemned for exercising
ceremonial magic (Zambelli 2007). Porta's magus is a decidedly
male figure who unites the physical dexterity of the trickster, the
experience of the alchemist, the erudition of the humanist, the
astrologer's command of mathematics, and the intuitive knowledge
of the psychic medium in order to embody a superhuman, ideal man
capable of manipulating everything and everybody. The magus must be
talented, rich, educated, and hard-working; magic is the most noble
part of philosophy for Porta (*Magia* 1558: bk. 1, ch. 2). Instead of a
priest or metaphysician in quest of the divine--as in Pico della
Mirandola or John Dee--(Harkness 1999), Porta's magus is
thus an artifex (a craftsman or mastermind) who knows how to
manipulate the natural and occult properties of certain bodies.
According to Porta, these qualities are occult because their workings
cannot be grasped by our intellect. Yet he infers that occult
properties derive from formal, not material causes--partly
because a very small quantity of matter often may have an enormous
effect (*Magia* 1558: bk. 1, ch. 8).



Magic is therefore a specific science of natural objects (animals,
herbs, stones), the servant or minister of nature; in Porta's
characteristic definition of natural magic, just as a peasant prepares
the soil to help nature produce its marvelous effects, so the natural
magus prepares matter in a special way to allow its natural (but
nevertheless occult) properties to appear. Structurally, this magic is
a form of applied Platonist metaphysics --in Ernst
Cassirer's words, an emanatist form of physics
("*emanatistische Form der Physik*" Cassirer 2002 [1926]:
128). In reasoning highly reminiscent of Marsilio Ficino's
(1433-1499) cosmology in the *De via coelitus comparanda* and the
*De amore*, Porta maintains that in the strict hierarchical order of
Creation the transcendent forms are directly affiliated with God; they
are projected into the world in various manifestations, first into the
Angels (or daemons), subsequently into the soul, and ultimately into
qualities (qualitates) via the elements, again of celestial origin, as
their instruments shape matter (*Magia* 1558: bk. 1, ch. 4).



But these theoretical speculations fill only a minor part of Porta's
two versions of the *Magia naturalis*. The bulk of these texts was
dedicated to more or less eccentric recipes: incubators for
hens' eggs, an improved camera obscura that won't invert
its images, tinctures to remove spots from your skin, ways to roast
animals alive and drug people, a magic lamp fuelled with hare's
fat that will make even respectable women strip naked (Kodera 2006,
Kodera 2020b). Next to these recipes, Porta tells his readers stories.
One is about a raging bull which becomes tame and docile when fastened
to a barren tree; another is about a hyena's shadow that will
silence barking dogs. Porta was one of the most popular bards of such
stories in his time. Much like today's consumers of science
fiction or fantasy literature, early modern readers seem to have
delighted in such accounts of inexplicable phenomena, familiar from
Classical literature and philosophy, such as Ovid's
*Metamorphoses*, Pliny's *Naturalis historia*, Aristotle's
*Problemata* and the spurious *De mundo*, and
the *mirabilia* (marvels) attributed to Albertus
Magnus. Marvelous performances of this sort were not limited to an
audience of ruling elites, but were peddled widely on
marketplaces. Wonder drugs and cure-alls filled books by a whole class
of semi-literate "professors of secrets" (*professori dei
segreti*) who eked out more or less glamorous livelihoods by selling
emetics and purges. Their drugs sometimes contained powerful (and
experimental) chemical substances, such as mercury oxide and other
products of alchemists' furnaces (Gentilcore 1998; Eamon 2010,
2017; Smith 2011).



Essentially, the art of the magus consists in channeling or
concentrating such natural forces by artisanal practices, for instance
by distillation.



Knowledge of such procedures allows the magician to exercise
considerable power in ordering and disposing bodies to reveal new and
amazing features. Generally, an object's visible traits, or
signatures, are indicative of its occult powers and those
powers' relationship to other objects, both higher and lower in
the hierarchy of being. This idea is also central to Porta's
doctrine of physiognomonics (discussed below). A side effect of this
universal connectedness of all things is that the world as a whole
becomes animated (Hankins 2003).



All things in the universal hierarchy of being are moved by the
(irrational) forces of attraction and repulsion they feel for one
another. Porta provides an impressive description of the macrocosmic
animal, the male and female aspects of which mingle in a harmonious
and well-coordinated way, which he expeditiously plagiarized (*Magia*
1589: bk. 1, ch. 9; Ficino 1989 [1489]: lib. 3, ch. 26). At a deep
level--and in a characteristic form of circular
reasoning--the cosmology of natural magic thus depends on the
workings of a decidedly erotic cosmology itself modeled on human forms
of sexuality (Kodera 2010). The postulation of an affective structure
permeating the whole of creation from top to bottom was vital to
account for the phenomenon of action at a distance (actio in distans),
which Aristotle had expressly ruled out in his *Physics* (7. 2,
244a14- 245b5, see Henry 2008).



Porta's magic is parasitically dependent on manipulating the
affective structures of love and hatred that bind together the
universe. The principle of universal affective correlations formed the
backbone of Renaissance natural magic in general. Porta credits this
doctrine to Empedocles (*Magia* 1558: bk.1, ch. 9), who held a
reputation as a magus among Porta's contemporaries (Kingsley
1995). These ideas were not only embraced by many of the preternatural
philosophers, but were already found in the preface of the *De
mirabilibus mundi* ascribed to Albertus, one of Porta's favorite
sources for many of his more unusual segreti.



It is thus no wonder that the lodestone has a prominent place in
Porta's performative practice and his theoretical endeavors.
Porta takes the attractive powers of magnets on iron as a paradigm for
magical attraction: the speculation is that all bodies have an
inherent property to attract certain other bodies. In the second
version of the *Magia* he plagiarized and popularized many basic
insights from an unpublished Jesuit source (Leonardo Garzoni), for
instance that the magnet has two opposite poles and the many tricks
that could be performed by dint of these attractive and repulsive
qualities of the lodestone (Copenhaver 1991, 2007, Ugaglia 2006,
Sander 2016, Kodera 2020a).



The magician capitalizes on the natural forces of love, hate,
attraction and repulsion inherent to the universe to act as a
matchmaker, and he produces marvelous offspring: many of the
magus' activities are akin to husbandry. (Again, this is an idea
also found in Ficino's De vita). Porta's *Magia* 1589 (bk. 2
and 3) contains long chapters on the production of monsters in the
vegetable as well as animal worlds (Kodera 2010).



A central topic for Porta is various technologies for attaining vision
of the miraculous. He supplies numerous recipes for drugs and magical
lamps designed to distort our perceptions (*Magia* 1589: bk. 8, ch 2),
some of which also have a strong theatrical orientation (including his
witches' unguent, lenses, telescope and camera obscura, Reeves
2008). For the most part, Porta's mirrors were not subjects for
speculation, as they had long been in metaphysics, theology, magic and
the divinatory arts. Neither were they primarily tools to produce
"objective or scientific data" (Daston and Galison 2007;
Smith 2009). Porta's experiments with lenses and mirrors (such
as the improved form of the camera obscura) fit more coherently into
the perspective described above: these devices function as generators
of marvels, with the objective of stirring spectators'
imaginations (Dupre 2007; Thielemann 2009). The resulting
images take on a form of existence that, like a phantasm, is halfway
between "real" and "imaginary" (Giglioni
2011).


## 3. Works on Astrology



Porta's tacit refusal to acknowledge the Aristotelian border
between sub- and supralunar worlds in cosmology is a salient feature
in his account of the hierarchy of being. This erosion of boundaries
easily leads to the assumption that the seemingly erratic movements of
objects in the sublunar sphere are actually less random than they
might appear, because they are governed by secret, divine principles.
Conversely, the direct causal nexus between divine powers and created
forms accounts for those objects' potential to operate in
seemingly miraculous, but actually natural, ways (*Magia* 1558: bk. 1,
ch. 5). Related to these ideas are the doctrine of universal animation
and the belief that superior celestial influx is mirrored in or
resonates with material objects.



Recently, some historians of thought have explained Porta's
endeavor in the context of Porta's (often covert) adherence to
the traditions of European Astrology and related magical doctrines.
And indeed Porta incorporates ideas developed in medieval Aristotelian
tradition, especially by Albertus Magnus, which later became an issue
for Pietro Pomponazzi and his followers. They have emphasized that
such ideas were believed to be in accordance with Aristotelianism and
the status of astrology as a science. (Weill-Parot 2013, Verardi
2018). While it is certainly true that Porta cultivated a life-long
interest in these theories (and presumably also in their practice), at
least his public attitude seems to have changed significantly. This
was certainly in part due to the fact that astrology had been
condemned in ever harsher terms in the last decades of the 16th
century, and to Porta's ensuing personal difficulties with
censorship. Probably in response to these pressures, Porta radicalized
his naturalism; it was indeed more profitable to write comedies and to
showcase marvelous inventions than to become involved in metaphysics.
Moreover, Porta was also highly sensitive to the individual
predilections of his addressees, who were more often than not
potential patrons. Even with the late and unfinished *Thaumaturgia*
Porta was again trying to cater to Rudolf the Second, that great
patron of the occult arts. Perhaps for the first time in his long
life, this unfinished work testifies to Porta's systematic
interest in demonology and Neoplatonic magic (Maggi 2015, Verardi
2018).



In the next section, we see some of the more inconvenient aspects of
Porta's theory of magic discussed here; its circular reasoning
and anthropomorphism reappear in Porta's ideas on
physiognomonics (Simon 1980; Vedrine 1986).


## 4. Works on Physiognomonics



Physiognomonics, a proto- or pseudo-science on the rise in the
sixteenth century, sought to identify the visible affinities between
all physical things. As is for instance amply evidenced in his
Phytognomonica Porta detected such affinities everywhere, from plants
and animals to the bodies and faces of humans, and even further up the
ontological scale to the appearance of the planets
(Muller-Jahncke 1990). Porta's physiognomonics provides
cartographies of the outward appearance of physical bodies aimed at
predicting the soul's hidden inclinations or dispositions (past,
present or future). Porta's massive effort to map the exterior
appearances of all animated bodies runs in tandem with the
contemporary medical approach towards cartographies of human bodies
(as well as landscapes), exemplified most notably by Andreas Vesalius
(1514-64) in his revolutionary anatomical studies. Incorporating
a huge array of classical and contemporary sources, Porta's
physiognomic texts are an outright summa of this branch of knowledge
and practice.



Within its own historical context, physiognomonics was viewed as a
scientia universalis, rational science as good as, or perhaps even
better than, the new anatomy, since it could be used for universal
description and as a means to identify character traits (Paolella
2015). In his circular reasoning, Porta's cosmos becomes more
and more anthropomorphic, as universal signatures are imprinted not
only into human beings, but also share these physical traits with the
stars, animals, herbs and even stones (as explained in Porta's
*Phytognomonica*) (Kahn & Perifano 2018).



Porta's physiognomonic assessments are based on resemblances in
external appearance: for instance, men with a dark, Saturnine
complexion evocative of dangerous animals are rendered very likely to
go to prison (*De ea naturalis physiognomoniae parte quae ad manuum
lineas spectat* ch. 12). This example highlights the aesthetics
structuring Porta's physiognomonics: beautiful bodies are also
morally good. There is a direct association between beauty, virtue,
success and health, as these traits all originate from a good
temperament, that is, from a harmonious mixture of the elements. A
monstrous body, on the other hand, indicates ill health, bad luck, and
dubious moral inclinations. (Kodera 2015)



A truly universal science, physiognomonics provides its master not
only with a key for decoding the ciphers written into human faces (by
relating them to the shapes of animals) or a manual for reading the
lines engraved into the palms of our hands, but also (as Porta
suggests) with diagnostic methods for understanding all of creation,
from plants to stars. As is amply advertised already in the prefaces
to all of his texts on physiognomonics, the art establishes a
metonymic relationship between inorganic bodies and psychological
qualities (Caputo 1990, Paolella 2004, Muratori 2017).



One important aspect of Porta's physiognomonics is that it is
not merely descriptive: bodies may be mapped and their future
predicted, but they are nevertheless in a constant state of flux,
transition, or mutability. Their essences are not exclusively
determined by an invisible substantial form (soul) derived from
unchangeable forms--and, in the case of human beings,
immortal--as in previous traditions, but (more than ever) result
from external circumstances. These environmental influences are
decisive for the fate of individuals whose expressions and appearances
are unstably shaped. A characteristic quotation illustrates
Porta's understanding of physiognomonics:



> 
> Through this art, we have helped many friends avoid dangers and ascend
> to honours. Shortly before I wrote these things, I counselled a friend
> of mine to avoid the company of a certain ugly and unlucky man, an
> advice he did not want to hear, as his acquaintance had promised him
> riches; at the end of the day, they were caught by the governor
> producing counterfeit money in a hide-out and shortly afterwards both
> ended on the gallows. (*Coelestis physiognomonia*, bk. 1, ch. 2)
> 



It has often been noted that Porta opens perspectives on the sinister
tradition of eugenics (Paolella 2015), not uncommon currency in
European intellectual culture since its articulation in Plato's
Timaeus (90), where a handsome body is stipulated as the abode of a
beautiful soul. Apart from the elemental influences altering body and
mind, which can be reduced to qualities perceived through touch (such
as hot/cold, dry/moist), Porta mentions nutrition, climate, and age as
determinants of an individual's mental and physical shape, not
only of human beings but also of animals and even of plants. Disease
may also alter an individual's mental disposition: as an
example, Porta mentions fevers--since they dry up the brain, they
may cause the patient to become more intelligent. Disease may even
instill a capacity for divination. Alterations in outward appearance
bear thus significant consequences for the individual's
behaviour and habits (*De humana pysiognomonia* bk. 6, ch.1).



From the perspective of religious orthodoxy, the crucial question
Porta addresses only with (well-advised) trepidation is whether a
change in exterior form can also cause alterations to the
soul--i.e., in the substantial and indelible form of humans (*De
humana pysiognomonia* bk. 1, ch. 20). Here, Porta takes the position,
more common to medical physiologists, that it is a physician's
intervention rather than moral philosophy that cures our bodies and
minds. On this view, the body becomes a potential stage for medical
intervention into the mental realm (Kodera 2010: ch. 8, Kodera
2015).



The concept of the temperaments or humoural mixtures in the human body
was originally developed to describe physiological body states: "The
four humours were real body fluids, to which largely hypothetical
origins, sites, and functions were ascribed" (Siraisi 1990: 105). In
late Antiquity and in the Middle Ages, the temperaments were
understood to fall under the reign of the stars, which influence the
generation and corruption of bodies in the sublunar sphere. In an
important conceptual step, Porta turns the tables, contending that
rather than being controlled by the stars, the medical humours are
actually universal descriptors structuring the entire cosmos. With
this move in a naturalistic direction, Porta strove to eclipse the
astrological elements of his theory. Even though in the Coelestis
physiognomonia he had declared astrology a vain discipline, Porta
added an important qualification to this dismissal: astrology is an
erroneous art, but only as long as divination from the stars is not
based on the perceptible features of heavenly bodies. Hence, a fine
physiognomonist will swiftly derive the relevant temperamental
features from the visible appearance of the planets. In this way, all
natural bodies remain substantiae signatae, cosmically predisposed
substances bearing inscriptions of universal signs. The astrological
system of categorization was restricted to the medical temperaments,
thus associating celestial bodies with a system of signs that
pertained to medicine and hence to a lower level in the hierarchy of
being. Instead of governing the lower bodies, the stars become subject
to the same laws as earthly bodies (*Coelestis physiognomonia*,
*proemium*, Paolella 2004). According to classical medicine, diseases
are caused by an imbalance between body fluids--the temperaments.
This was a notable shift in terminology and concept: for in the first
version of the *Magia naturalis*, Porta had maintained that form had
been the decisive factor for the occult property of a thing: now he
aligned these properties to elemental qualities (Verardi 2018).



Initially, Porta's naturalized version of astrology was probably
a mere maneuver for detouring around the ecclesiastical censorship of
the divinatory arts; in the first edition of the *Magia* (1558) Porta
had fully embraced astrological causation, as well as the decisive
role of an auspicious astrological moment for magical operations,
especially the confection of talismans as described by Ficino in the
*De vita* (*Magia* 1558: bk. 1, chs. 15-17; Trabucco 2002,
2005).



However, close alignment of astrology with medical humours and
physiognomonics is well in accordance with Porta's larger aim of
naturalizing the entire cosmos. These interactions also have bearings
on Della Porta's theater, which is not very suprising indeed, as
the traditon of physiognomonics was developed in the ambit of the
classical stage, notably in *Theoprastus Characteres*, a text that
describes the typical features of comical personae (Kodera 2015,
Refini 2017). As many students of Porta's theater noted,
sometimes outrightly grotesque displays of pysiognomics figure
prominently in his numerous comedies. (Clubb 1964, Gherardini, 1971,
Kodera 2015)


## 5. The Book on Ciphers



When seen in the context of the doctrine of physiognomics, it comes as
no surprise that Porta authored a book on ciphers, as he believed
himself endowed with a special ingenuity for decoding all forms of
texts. Renaissance cryptographers in general had a penchant for
mystery and the preternatural, as evident from Johannes
Trithemius's *Steganography*, for example. Trithemius,
the Abbot of Sponheim, got in trouble with his ecclesiastical censors
because he used a complex numerological series of demons' names,
arranged on Lullian wheels, for encryption (Arnold 1991). With their
aura of mystery, ciphers thus qualified as a congenial topic for
Porta's general outlook as a popularizer of secrets and as
inventor of marvels. *De furtivis litterarum notis* is apparently the
first text on this topic that not only explained various ways to
encrypt messages, but also gave detailed instructions on how to
decipher coded messages (Strasser 2008). The art of cryptography had
the advantage of being perhaps less wicked than necromancy, while
still attracting the attention of powerful political patrons. For
someone aspiring to be the adviser and protege of one of
the more powerful worldly rulers, it was therefore not an unwise
choice to write such a book.


## 6. Art of Memory



Porta's approach to the ancient art of memory is markedly iconic
(rather than architectural), as typical for many medieval and early
modern formulations of mnemonics and in this respect he claims to have
surpassed the classical authors on the subject. In order to organize
the memory, Porta recommends constructing a mental picture gallery
populated with striking images of persons or groups of persons. He
also mentions the important role of contemporary paintings and
sculptures by the foremost artists of his time, including Titian,
Rafael and Michelangelo. Porta maintains that restoring the memory is
like refreshing the colors of a faded painting. Especially in the
Italian Arte del ricordare, Porta recommends graphic erotic fantasy,
such as sodomitic intercourse, as the strongest memory aid; to
illustrate his point, he gives examples from Ovid's
Metamorphoses and from Apuleius. In a manner clearly reminiscent not
only of his recipes with hallucinogenic drugs but of his naturalist
approach in general, Porta maintains that such erotic
images--phantasmata--are so potent that they may even be
able to destroy the memory (Bolzoni 1990, 2002 Kodera 2019).


## 7. Botany, Agriculture, Horticulture



In *Villae* (*Estates*) Porta presented a true summa of
ancient and modern forestry, agriculture, and horticulture as it had
been known and practiced in Europe. Villae are organized in a scenic
manner, "an imaginary round tour through an open air
theater" (Orsi 2005, 53). The reader is guided through the
diverse zones of an imaginary vast country estate. Some scholars have
claimed that the *Villae* can also be read a veiled criticism of the
policies of Spanish agriculture (Orsi 2005, Rusu 2020).



Emphasizing first hand experience, Porta's *Villae* focuses on
plants cultivated in Puglia and the Capitanato, the province
surrounding Naples. Even though *Villae* was not a big success, it
implicitly catered to a way of life that took its inspiration from
Cicero's ideal of an independent life (Orsi, 2005, 2008). This
went well with a trend in Porta's day among the ruling classes
to move to the countryside, which also resulted in the construction of
some of Andrea Palladio's most impressive rural villas.



Referring to classical treaties by Theophrastus, Columella, Pliny,
Virgil, and more recent authors as for instance Pontano and
Sannazzaro, Porta discusses plants that had been known and in use
before the discovery of the Americas. Even so *Villae* was innovative in
several respects: it was the first text to dedicate an entire treatise
to the cultivation of olives, as well as one on on grafting. This
latter topic is especially interesting because it firmly links Portas
agriculture to his ideas on natural magic. In general the *Villae*
betray an implicit astrological agenda as Porta conceives of plants as
recipients of celestial influx. As Wechsel, Porta's German
publisher of the *Villae*, noted with exasperation, the long manuscript
was in such a terrible state, fraught with so many grammatical and
orthographic errors that it had to be most thoroughly emended; yet and
regrettably in several places the meaning of a passage "was not
to be recovered by another Oedipus." Even though Wechsel
exonerates the author by putting the blame on a corrupt manuscript,
his vindication of Porta remains ambiguous because the editor also
says that the extent of his emendations become obvious in a comparison
of his edition to the *Olivetum*, which had been published eight years
earlier, in 1584. Much the same can be said about the *De furtivis
litterarum notis*, which is fraught with misspellings, no small matter
in a text that is on decoding. These examples indicate that Porta was
much more of a prolific author than a careful editor of his texts.


## 8. Mathematics



Even though in structure it was ostensibly orientated on
Euclid's *Elements*, Porta's *Elementorum
curvilineorum libri tres* (1601/1610) flopped, probably because
Porta had coined so many fantastic new words for (allegedly) new
geometrical shapes, which was perhaps and with hindsight one of his
most original ideas (Saiber 2017). In fact, Porta's knowledge of
classical and contemporary mathematics seems to have been vast, but
superficial. Using a language that is both colloquial and empirical,
Porta's mathematics refers to concrete objects and sensory
evidence, rather than to logical-deductive definitions. Napolitani
accordingly described Porta's (erroneous) proposal for a method
to squaring the circle as sleight of hand. In Porta's
presentation it emerged as yet another segreto that had to be arranged
in ways that merely appear to be credible, appeal to the senses, and
create marvel. Generally the ways of *Elementorum* is foreign to
contemporary discussions in the field: Accordingly both his editions
were not commented on by the foremost mathematicians of his time
(Napolitani 1990).


## 9. Optics and the emergent experimental culture



Porta's ideas on optics gradually developed over his long career. His
approaches to the field were holistic and his characteristic
perceptual understanding of images was not necessarily geared towards
the development of a coherent optical theory. Motivated by an interest
in the theatricality such devices could produce, Porta's optical
endeavors were geared towards controlling or manipulating visual
perception (Dupre 2007). The texts on plane and curved mirrors,
lenses, and glass orbs are closely tied to devices which had the
capacity to generate marvelous optical illusions (such as cabinets of
mirrors, images that appear to be suspended in the air, spy-glasses,
or the camera obscura). The same is true of Porta's optical
analysis of the anatomy of the human eye.



For example Porta's experiments with the construction of
parabolic mirrors made from glass resulted in the invention of an
improved camera obscura that--in theory at least--had the
potential to produce images that were not upside down. Porta
recommends this artifact, a combination of a convex lens and a concave
mirror, for setting up theatrical shows. He uses the same setup of
lenses and mirrors for his spy-glass. This telescope became a very
important tool for astronomers during the scientific revolution. Yet,
in Porta's day, telescopes were usually considered to be
instruments for image-making rather than tools for measuring the
positions of stars (Dupre 2007, Reeves 2008, Dijksterhuis
2017).



In recent years, some researchers on Porta's optics have
emphasized that this was not necessarily a shortcoming. Porta's
hard work to improve and investigate the qualities of optical devices
with the potential to create marvel generated not only some important
discoveries, it also contributed to optical theory. The problem of the
relationship between the point of inversion and the focal point in
curved mirrors is a case in point, because Porta's work contributed to
the emergence of the concept of virtual and real images (Borrelli
2014, 2017). In this case, Porta's hands-on approach proved
particularly fruitful as it successfully translated artisanal
knowledge to the domain of literary culture of the sixteenth century.
This was highly innovative, because optical theorists still were
largely ignorant of the heuristic potential of the new artifacts
produced from *cristallo*, or Venetian soda glass.



Essentially, Porta's strategy consisted in first gaining an
understanding of the effects of simple artifacts and then building on
that knowledge to construct (or imagine) ever more complex devices.
His particular mode of investigation of the physical properties of
artifacts in conjunction with diagrams served Porta to design new
artifacts with even more amazing properties. Borrelli has described
this as a process of "bottom-up modeling" and as markedly
different form medieval and traditional perspectivist optics.
Encompassing a more comprehensive approach to optics than for instance
Johannes Kepler, Porta conceived of optics as related to images as we
perceive them and not to what rays do. This led Porta to compare the
human eye to a camera obscura; it was a claim that met the criticism
of Kepler (Borrelli 2014, 2017, Dijksterhuis 2017). Yet, and in marked
difference to Francis Bacon, who used Porta's experiments as
openings for new experiments, Porta's endeavors were geared
towards the production of artifacts that would render stable and
repeatable effects. This approach also made up for an important part
of Porta's reception in seventeenth-century England. (Jalobeanu
2020).



Despite the many contradictions and problems in Porta's works that
until recently have lead to an overwhelmingly negative assessment of
his role in the history of science, more recent studies have
identified Porta's combination of artisan culture and
diagrammatic methods as extremely important for later research
strategies in the experimental science of the seventeenth century. As
Borrelli has claimed in a series of publications, Porta's
obdurate ways of working with real artifacts in his experimental
space, in conjunction with diagrams and other paper tools would, with
hindsight, easily translate into what was soon to become modern
laboratory practice. Even so, these efforts came comparatively late in
Porta's long life. The *De telescopio* remained in manuscript
draft and did not represent Porta's public persona as magus.
Nevertheless these texts testify to the author's versatility in
accomodating his own endeavor to the most recent trends in early
modern science. (Frangenberg 1991, Fumikazu 2011, Borrelli 2014,
2017).



Hence, by the standards of his day, Porta's ceaseless endeavors
were neither unsophisticated, undignified, nor disingenuous. Quite on
the contrary, Porta's activities could well rank as privileges
of members of the upper classes, and especially so as long as they
were geared towards theatricality, and the planning of devices of
wonder. Accordingly, during the seventeenth century Porta was
perceived as a virtuoso rather than as a natural magician. (Jalobeanu
2020). As many scholars have aptly pointed out, such artifacts did not
necessarily need to be useful or effective or to engender rational
reflection. The production of marvel was a respectable end in itself
(Wolfe 2004 Lazardzig 2008 Eming, 2020).


## 10. Distillation



Distillation was a key artisanal model for Porta, because he
maintained that by means of this technology, one could extract the
essences, that is the 'spirits' or souls of all things. Porta was here
following a tradition in alchemy that in his day was associated with
Arnaldo da Villanova and Ramon Llull. In accordance with this
tradition, Porta applied the conceptual model of distillation to many
different arts: to describe techonologies for the purification of
metals, to meteorological phenomena, such as rain or clouds and even
as a design for processes of social reform (conceived of as a
purification of society). In this last sense Porta's art of
distillation resonates with his claims about policing society made in
his physiognomics. This art spilled over into Porta's ideas
about the refinement of substances: for the *De distillationibus* also
describes the use of different animal shapes of alembics for the
distillation of different substances. Thus for instance Porta
maintains that a bear-shaped alembic is ideal for the refinement of
coarse substances (Kahn & Perifano 2018, Perfetti 2001, Eamon
2017, Borrelli 2019).


## 11. Meteorology



As in his optics with the model of the camera obscura and the eye, so
Porta explains meteorological phenomena by experimental simulation. By
showing how water condensates in some of his artfully designed
glass-works he demonstrates that rain is caused by condensation of air
into water; in similar setups he evidences how rain or winds are
generated by the mixture of hot and cold air (Borrelli 2019). Even
though this was an undoubtedly an innovative approach, such
'word machines'--automata that simulated cosmological
phenomena--were allegedly constructed by Archimedes. In early
modern Europe such artifacts had been a formidable topic in learned
natural magic at least since Ficino's day (Toussaint 2002). From
this perspective, Porta's experimental set-ups point as much in
the direction of modern meteorology as exemplary virtuoso
artisan's culture during the seventeenth century, such as
Cornelius Drebbel's artifacts that simulated sea-tides
(Dijksterhuis 2017).


## 12. Repetition, Evolution and Adaptation of Ideas in different contexts



Porta recycled and gradually expanded many of his ideas and
instructions in different works over long periods of time, to appear
frequently in enlarged or amplified versions. Thus, some topics
evolved into separate treatises; at other times, Porta attempted to
reformulate his ideas to suit ecclesiastical regulations. This was
prominently the case with Porta's ideas on physiognomy discussed
above. In other instances, Porta sought to adapt his ideas to the
emerging scholarly standards of the new science of his day. A case in
point is his treatment of powers of diverse siphons to lift water or
to separate different fluids (for instance water from wine) from each
other. What seems to have been originally intended as a party gag in
the first version of the *Magia naturalis* (where Porta probably
plagiarized from a chapter in Girolamo Cardano's *De
subtilitate*), migrated to the enlarged version of the *Magia*, to become
eventually a key topic in *I tre libri spiritali*. Here, amidst boasting
that he could build structures that would be capable of lifting water
up to the highest mountains, Porta ties his claims about the powers of
siphons to a discussion on the impossibility of the vacuum. Finally he
discusses similar experimental devices in the *De aeris transmutations*.
They were eagerly copied and amplified by the Jesuit Gaspar Schott,
whereas Francis Bacon significantly developed them into new
directions. (Trabucco 2016, Jalobeanu 2020)


## 13. Porta's Place in the History of Philosophy



In most encyclopedias over the centuries, Giovan Battista Porta is
remembered for particular inventions--for instance, the telescope
(Reeves 2008; Saito 2011; Balbiani 2008). This tendency to
decontextualize Porta's (vast) oeuvre by treating it as a quarry
of ideas actually dates back to his contemporaries: scholars and
theologians as varied in temperament and intellectual inclination as
Francis Bacon (1561-1626), William Gilbert (1544-1603),
Athansius Kircher, S.J. (1602-1680), Christian Knorr von
Rosenroth (1636-89) or Georg Philipp Harsdorfer (1607-1658).
Thus, Bacon discusses and transforms many experiments form
Porta's Villae in his Sylva sylvarum (Rees 1990 Rusu 2020). In
very different ways Kircher, though overtly condemning Porta,
knowingly plagiarized his segreti (Vermeir 2012). William Gilbert
(1544-1603) felt it necessary to take issue with the animistic
theories that Porta used to explain magnetism (Kodera 2014). Tommaso
Campanella (at that time still a faithful disciple of Bernardino
Telesio (1508/9-1588) had already deplored Porta's lack of
method, which precluded the development of a new metaphysics of nature
(Eamon 1995). For several decades after his death, Porta's name
remained tied to witchcraft on both sides of a controversial debate.
Thus Bodin's indictment of Porta's naturalistic explanation of
the sabbath was repeated in Martin Anton Delrio's (1551-1608) highly
influential *Disquisitionum magicarum* lib. vi (1599), an encyclopedic
inquiry into the subject. Frederich von Spee (1591-1635) cites Porta
in what by then had become a single-handed criticism of the
persecution of witches. Thus the recipe for the witches' unguent
in Spee's *Cautio criminalis seu de processio contra sagas* (1631)
is used as evidence against the claims of Bodin and Delrio.



On another front Porta's physiognomics found an echo in
Harsdorfer's universal linguistics. In his Frauenzimmer
Gesprachspiele (1641-49). Physiognomics figures as one among
countless linguistic systems, as part of a characteristically baroque
science of signs and symbols. Harsdorfer aligned Porta's
physiognomics with the influental Italian tradition of theorists of
art such as Cesare Ripa Guazzo, Capaccio, Ferrante Pallavicion or the
Bargalli Brothers. The influential poet, cabbalist and theosophist
Knorr von Rosenroth (1636-89) produced a careful and nuanced
translation of Porta's *Magia naturalis* into German (1680).
(Battafarano 1990, Balbiani 2008 ). In France too both editions of the
*Magia* remained very popular throughout the sixteenth century: in the
learned world, Mersenne commented on Porta's optics. (Beaulieu
1990).



It is only in recent Porta scholarship that his endeavor has been
encompassed in a less fragmented way. Generally speaking, Porta
reacted to the challenges of ecclesiastical censorship by attempting
to abstain from metaphysical speculation and theology; there is good
reason to believe that Porta's naturalist stance was actually a
consequence of ecclesiastical persecution (Trabucco 2002, 2005).
Accordingly, he developed a strictly natural magic--natural in
the sense that the formal principles driving the movement of things in
the cosmos were taken as "occult", with many causes of
their often marvelous properties per se unknowable to us.
Porta's experiments thus prudently sought to eclipse all hint of
religious topics, including God, the soul, and demons. Firmly rooted
in a southern Italian intellectual environment, Porta also is silent
on Copernicanism or the discovery of the new world. He is thus one of
the emblematic figures at the threshold of modernity (Torrini 2016).
By eliding discussion of the metaphysical and religious implications
of his experiments, Porta tends to direct attention to the physical
preconditions and occult yet natural qualities that allow for
spectacular manifestations of portentous qualities in physical bodies,
whether human, animal or vegetable. The infamous recipe for an unguent
employed by witches is a good example of Porta's approach: the
nocturnal flights and orgiastic encounters with demons and the devil
that represent witchcraft's stock-in-trade are, according to
Porta, in fact mere hallucinations caused by belladonna--a
material substance with occult but non-demonic properties (Balbiani
2001). This explanation rests on the extent to which the human soul is
affected by the occult properties of natural substances. Like Pietro
Pomponazzi (1462-1525), who with his *De incantationibus* had
sought to naturalize all miracles, Porta seeks to bypass the question
of "proper" miracles produced by divine intercession. Yet,
and in contrast to Pomponazzi, who sought to eliminate as much as he
could of the preternatural, Porta continued to believe fervently in
occult sympathies up to his last unpublished works. Thus, and perhaps
for the first time in Porta's long career, the late *Thaumaturgia*
systematically address Neoplatonic demonology (Maggi 2015). For Porta,
the visible and perceptible qualities of certain material dispositions
become embodied signs of a larger and ultimately divine cosmic order
to which all natural bodies, including human beings, are subject.



Porta's account thus has the marked and unorthodox tendency to
eclipse human agency aside from the figure of the natural magus, who
by dint of his natural talent, erudition, and wealth is in a position
to manipulate and command the natural properties of many substances
and objects. Porta himself cultivated an image of being far keener on
staging marvellous experiments or divulging (more or less credible)
secrets than on investigating, say, theoretical foundations of natural
causation. His approach geared to the naturalization of the human
being--body and mind --is perhaps the most suitable focus
for studying his thought; here his ideas can be linked not only to
contemporaries of his such as Giordano Bruno but also to the tradition
of libertine philosophers leading up to Marquis de Sade
(1740-1814).



When measured against the sophisticated metaphysical backdrop of
Neoplatonic Renaissance magic, Porta's theoretical approach
appears disappointingly simple and rather epigonic--or, as
Borrelli (2014) has argued, unsystematic and thereby unfettered by
doctrinal ballast and open to innovation. Upon closer scrutiny, a very
complex picture emerges. When one considers Porta's numerous
literary and scientific texts, he must be ranked among a highly
influential group of philosophers / scientists / magicians including
Marsilio Ficino, Giovanni Pico della Mirandola (1463-1494),
Pietro Pomponazzi, and Agrippa von Nettesheim (see Agrippa 1991).
Under shifting historical circumstances and in various ways, these
"preternatural philosophers" shared a deep interest in the
marvelous and the demonic arts (Verardi 2018, Weill-Parot 2013).



Within this tradition, Porta was a relative latecomer; he dedicated
his endeavor to a "sublime science" that catered to a
courtly environment increasingly subject to absolutist leadership
(Daston and Park 1998). Indeed, Porta managed to attract the attention
of the most powerful patrons in the occult arts and alchemy, among
them Emperor Rudolph II and Philip II of Spain. When seen in their
proper historical context, Porta's literary and scientific
activities appear as a particular form of self-fashioning for the
emerging class of courtiers under absolutist rulers (Greenblatt 1980;
Biagioli 1991; MacDonald 2005). Hence, viewing Porta's oeuvre as
a product of this courtly environment helps us understand his
contribution to a characteristic form of comportment, where the
practice of deception and dissimulation is tied to the crafty staging
of marvellous appearances (Snyder 2009; Kodera 2012).



This topic of the marvellous (*meraviglia*), and of emotions elicited by
attendant stupefaction, is so essential for Porta that he projects it
onto the whole of creation, thus endowing it with the status of a
universal law. In a crucial passage from the *Magia* 1558, he writes
that Nature herself--the great female magician--creates all
her wonders out of delight in her own shows (bk. 1, ch. 9). Both this
anthropomorphic perception of nature and the importance accorded to
marveling in it reveal the close affinity between Porta's
magical practices and his texts for the stage. Porta evidences a keen
sense for media's power to manipulate individuals and masses
alike by way of drugs or optical deceptions, wondrous performances,
and the employment of the physical traits of individual human beings.
He believed that our physiognomonic features, the shapes of our
bodies, are indicative of hidden inclinations (for this reason, a
master physiognomonist may speedily detect criminals and other abject
persons). Hence, throughout Porta's oeuvre we can detect the
link he establishes between policing, naturalizing and assimilating
human beings among other animals, all under the sway of occult but
natural astrological influences. With his works on physiognomony,
Porta undoubtedly sought to offer his services to absolutist rulers
and courtiers.