## 1. Life and Works


### 1.1 Life



Little is known about Iamblichus' life and career, since
Eunapius of Sardis' biography of Iamblichus (*Lives of
Philosophers and Sophists* V [Goulet 2014, Baltussen 2023])
is merely hagiographical in nature. His birthplace is traditionally
taken to be Chalcis ad Belum (modern Qinnasrin), although support has
been voiced in favor of a different Chalcis, Chalcis sub Libanum
(Aliquot 2010: 307 and n. 7). What is uncontroversial is that
Iamblichus hailed from a very influential Syrian family, the
Sampsigeramids of Emesa (Damascius, *Philosophical History*,
Athanassiadi 1999: 334.10-14 [Zintzen 1967: 2.8-10]), who
had gained access to the Imperial throne along with Elagabalus
(218-222).



Eunapius gives Anatolius and then Porphyry as Iamblichus' two
teachers, and there are no decisive reasons to doubt this: on the one
hand, it is evident that he was influenced by the kind of theological
arithmology Anatolius championed; on the other hand, Porphyry
dedicated his treatise *On the "Know thyself"* to
Iamblichus (Stobaeus, *Anthology* III, 21, 26) and provides
information about the philosopher's son (*Life of
Plotinus* 9). Since this son is said by Porphyry to have married a
Roman aristocrat, it is very likely that Iamblichus studied in Rome
under Porphyry, who would have carried on the philosophical circle
Plotinus had founded in 244. Dalsgaard Larsen's (DL-1972: I,
38-39) supposition of a prolonged stay at Alexandria is dubious
at best.



After a break with Porphyry that seems impossible to date with
precision, Iamblichus settled in Syria. Although he is known to have
owned an estate in Antioch's suburb of Daphne, it is now
accepted that he settled in Apamea, where Plotinus' first
disciple Amelius had previously moved. There, welcomed by a wealthy
notable, Sopater, he founded a flourishing school: we know about a
dozen of his students (see below,
 Section 2.4),
 among whom the most conspicuous are Sopater himself, who died because
of a plot at Constantine's court; Aedesius, who moved the school
to Pergamon; and Dexippus, the only disciple of whom we still have a
philosophical work (a commentary on Aristotle's
*Categories*). Apart from Eunapius, evidence about
Iamblichus' whereabouts in Apamea is to be found mainly in
Libanius (e.g. *Ep.* 1389.13-14) and, above all, in the
letters by an anonymous Syrian sophist whose correspondence with
Iamblichus was preserved among the genuine letters of the emperor
Julian (e.g. Pseudo-Julian, *Ep.* 78 and 79 Wright).


### 1.2 Works



Few of Iamblichus' works are preserved in the direct manuscript
tradition. Four of these texts pertain to a summa *On
Pythagoreanism* (conflicting testimonies exist about its title:
cf. O'Meara 1989: 32-33): *On the Pythagorean
Life*; the *Protrepticus*; *On General Mathematical
Science*; and an *Introduction to Arithmetic* based on
Nicomachus of Gerasa's treatise of the same name. Sadly, they
are for the most part impersonal works: the *Protrepticus*
consists in lengthy quotations from previous hortatory literature, and
its interest mostly lies in the fact that it provides evidence for
valuable lost works (most notably Aristotle's own
*Protrepticus* and the so-called *Anonymus Iamblichi*),
while *On the Pythagorean Life* plagiarizes previous
biographies of the master, although it certainly contains valuable
insights on Iamblichus' conception of the "divine
man". Neither of these works seems to have had any impact over
the subsequent course of philosophy, whereas *On General
Mathematical Science* was at least a formative influence on
Proclus' commentary to Euclid's *Elements*, as well
as on Syrianus' commentary on *Metaphysics*
M-N (see DGU-2020). It also provides the basic material
for the reconstruction of Iamblichus' philosophy of mathematics
(see below,
 Section 4).
 For a general characterization of *On Pythagoreanism* and its
context, see Huffman (2006 [2019: sect. 4.4]).



The most important extant treatise by Iamblichus, however, is the
*Reply of Master Abamon to Porphyry's Letter to Anebo, and
Solutions to the Difficulties Contained Therein* (abbreviated to
*Reply to Porphyry* and traditionally known as *De mysteriis
AEgyptiorum* since Marsilio Ficino's original Latin
translation: see SS-2013: ix-xxi). The work is a defense of
Pagan religious practice (sacrifice, prayer, divination etc.; on the
latter, see Timotin 2022) against the objections raised by Porphyry,
and to serve this purpose it introduces several philosophical
developments on the divine nature and orders, as well as the
pretensions of the human soul. The whole debate is framed with a
fictional Egyptian scenario: Porphyry had raised his objections in an
epistle addressed to Anebo, an Egyptian priest, while Iamblichus wrote
his reply under the assumed guise of the Egyptian prophet Abamon.
While it had limited direct transmission (the only ancient testimonium
being Proclus, *In Timaeum* I, 386.8-13 [D-1973: Fr. 38],
although Taormina (2014) expressed reservations), its importance as a
touchstone against which one can safely compare what can be gathered
from other sources is invaluable.



The bulk of what remains of Iamblichus' work consists in approx.
800 fragments and testimonia. Of these, the extensive excerpts given
by Stobaeus of a work *On the Soul* as well as a dozen
*Letters*, which have been the object of multiple independent
editions, stand out as the most coherent, if not necessarily the most
original. By far the most influential part of his philosophical
output, his *Commentaries* on key works by Plato and Aristotle
are all lost, although in almost two cases (his commentary on the
*Categories*, transmitted by Simplicius; that on the
*Timaeus*, transmitted by Proclus), quotations are so numerous
that one can safely establish the main features of the exegesis given.
Of the other works Iamblichus wrote commentaries on, the most
important ones are the *Alcibiades*, the *Philebus* and
the *Parmenides*, while the existence of a separate, continuous
commentary on Aristotle's *De anima* was questioned by
Blumenthal (1974). A richly annotated edition of the Platonic
fragments was given by D-1973, while DL-1972 collected all fragments
known to Dalsgaard Larsen as an appendix to his monograph, although
his work can barely be described as an edition. Another collection
focusing on Aristotelian exegesis was produced by Romano [R-2012].


## 2. Iamblichus' Place in Greek Neoplatonism


### 2.1 The second founder of Neoplatonism



Iamblichus' significance in Late Antique philosophy can hardly
be overestimated. Karl Praechter described him as the second founder
of Neoplatonism after Plotinus and argued that Iamblichus'
position was similar to that of Chrysippus in ancient Stoicism
(Praechter 1910: 143). This statement aptly expresses
Iamblichus' historical and philosophical significance, but needs
qualification: unlike the Stoa, "Neoplatonism" is not an
ancient philosophical school, but a modern historical category (whose
reliability scholars are sometimes inclined to question: see Catana
2013). Iamblichus is likely, as was mentioned above
 (Section 1.1)
 to have been a student of Porphyry who was, in turn, a student of
Plotinus. Iamblichus' school was, however, separate from that of
Plotinus, both in time and in place: consequently, despite late,
ideological attempts to reconstruct a continuous "golden
chain" of Neoplatonist exegetes (see, e.g., Hierocles, *De
Providentia*, *apud* Photius cod. 214, 173 a; Proclus,
*Platonic Theology* I, p. 6.16-7.8), there is no
institutional continuity between Plotinus and Iamblichus and, from
this point of view, the situation is different from that of the
ancient Stoa. Iamblichus is not the second founder of the Neoplatonic
school for the simple reason that there is no unitary Neoplatonic
school in Late Antiquity. What scholars call Greek Neoplatonism is
actually a multifaceted philosophical movement that covers some three
centuries and includes several schools scattered throughout the Roman
Empire: these schools certainly shared doctrines and methods, but
their relations were sometimes close, sometimes much more tenuous.
Certainly, Iamblichus accepts and further develops some distinctive
features of Plotinus' philosophy and he can be seen as a
follower of Plotinus and Porphyry: this holds in particular for
Iamblichus' general metaphysical and philosophical approach, for
his account of the One and of the first principles, for his exegesis
of some works such as Plato's *Parmenides* and
Aristotle's *Categories*. On the other hand,
Iamblichus' original position *vis-a-vis* Plotinus
and Porphyry emerges clearly with respect to both his theories and his
methods (see Taormina 1999).


### 2.2 Exegesis



One of the most conspicuous of Iamblichus' contributions to
emerging Neoplatonism regards his views on exegesis. A typical Late
Antique intellectual in this respect, Iamblichus considers the written
work of authoritative figures to be sacred and claims to be a mere
interpreter of their true, deeper meaning (*nous*).



Four overarching principles govern Iamblichus' exegetical
practice. First, the idea that every authoritative work is fully
self-consistent and strives to demonstrate a certain thesis which acts
as its "goal" or "target" (*skopos*).
This principle is applied rigorously: for instance, since the
*skopos* of the *Timaeus* is the theory of nature, this
means that even the work's prologue, however autonomous it may
seem at first glance, should be interpreted in this way (*In
Timaeum* [D-1973: Fr. 3]). This amounts to considering literary
works living organisms, in accordance with what Plato writes in
*Phaedrus* 264C (see Coulter 1976: 73). Guidelines to
determining a given work's *skopos* are found in a late
anonymous composition, the *Prolegomena to Platonic Philosophy*
(SSSS 21-23).



The same source (SS 26) provides a list of twelve Platonic
dialogues (10 + 2) which, according to Iamblichus, offer an overview
of his philosophy and thus encompass the whole theory of reality. The
list starts with the *Alcibiades*, taken as an introduction to
philosophy and thought to contain the first ten dialogues, as if it
were a "seed" (*In Alcibiadem* [D-1973: Fr. 1). The
remaining dialogues are subsequently arranged according to the
different branches of philosophy (as Porphyry had done with
Plotinus' *Enneads*), while the Aristotelian distinction
between *praxis* and *theoria* is simultaneously
taken into account. *Praxis* or ethics is exemplified by the
*Gorgias* and the *Phaedo*, the former representing
politics, the latter catharsis (in accordance with Iamblichus'
conception of virtues, on which see below,
 Section 7.2).
 Then comes *theoria* where, as it seems, the
*Cratylus* and the *Theaetetus* are taken to provide
Plato's account of logic (the former teaching names, the latter
concepts); then come the *Sophist* and the *Politicus*,
which supposedly deal with physics--however strange this may seem
to us--and finally the *Phaedrus* and the
*Symposium*, which deal with theology. The crowning dialogue in
the first cycle is the *Philebus*, because its *skopos*
is the all-transcendent Good. Then, as a recapitulation of the first
cycle, we find a second one consisting in only two works (both of
which, remarkably, feature main characters other than Socrates): the
*Timaeus* and the *Parmenides*, the former subordinated
to the latter as physics is to theology, although both display a
degree of perfection and thus are expected to embrace the whole of
Plato's philosophy. This curriculum principle, then, was
supposed to bring an author's *oeuvre* into
accordance with itself, just as the *skopos* postulated organic
unity in a single text.



All that was left at this point was to establish harmony between
different authors; and this is where *sumphonia* or
"agreement" comes into play. Building on Porphyry's
efforts (as opposed to Plotinus' views), Iamblichus fully
integrated Aristotle into Platonism (see
 Section 5
 below); he also took into account Pythagoras and the
pseudo-Pythagorean corpus (see
 Section 4.3).
 References to other schools are scarce and mostly critical.
Iamblichus' philosophical authorities, then, are Plato,
Aristotle, and the Pythagoreans; they were complemented by several
texts held to be divinely inspired, of which the two most important
ones are the *Chaldean Oracles* (a second-century collection of
verse oracles which provide a Platonic-influenced revelation mostly
based on the *Timaeus*, and which develop a dualistic view
about matter and a divine energy called "fire") and the
pseudo-Orphic *Rhapsodies* in 24 books. The *Chaldean
Oracles* at least are known to have been commented upon by
Iamblichus, in a huge commentary comprising at least 28 books
(Damascius, *De Principiis* II, 1.5-8). (on
Iamblichus' religious views, see below,
 Section 6.3.)


### 2.3 Philosophy and theology



Iamblichus brought about a shift towards religion and theology in
Neoplatonism which proved crucial for the later development of this
movement and for its Christian appropriation (see Lecerf and Taormina
2022). The *Reply to Porphyry*, where Iamblichus rejects
Porphyry's over-confident intellectualism in theological and
religious matters, is certainly our major source on debates in early
Neoplatonism. Scholars have traditionally described Iamblichus'
stance as irrational, contrasting it with Plotinus and
Porphyry's rational and philosophical approach (see Dodds 1951:
285-298). Recent scholarship, however, has effectively
questioned this view (see Tanaseanu-Dobler 2013). In his
*Reply to Porphyry* (I, 2 [SS-2013: 4.5-5.11]) Iamblichus
distinguishes three disciplines, each with its own distinctive
methods: philosophy, theology, and theurgy. Theurgy certainly goes
beyond reason and philosophy, but Iamblichus' appeal to theurgy
and rituals is based on sophisticated philosophical views and
arguments dealing with the nature of divine beings and the status of
human souls (see below,
 Section 6).
 It would therefore be misleading to draw a strict opposition between
theurgy and rational methods. What is distinctive about Iamblichus
*vis-a-vis* Plotinian Platonism is the thorough
integration of theological traditions into his account of reality.
This emerges in two related areas. Whether or not he wrote a work by
this title, Iamblichus is the first Neoplatonist to develop a
"Platonic theology" (see Proclus, *Platonic
Theology* III, 44.1-5 [Saffrey & Westerink
1968-1997]). This approach will be carried further in Athenian
Neoplatonism, especially by Proclus. Plotinus had already connected
the hypotheses about the One in the second part of Plato's
*Parmenides* with his distinction of metaphysical principles
(see *Enn.* V, 1.8). Iamblichus goes one step further in that
he connects the metaphysical reading of this dialogue with the gods of
the Greek pantheon. His interpretation of Plato's
*Parmenides* can therefore be described not only as
"metaphysical" but also as "theological". In
addition to this, Iamblichus provides a harmonising account of the
different theological traditions, again paving the way for the later
developments in Athenian Neoplatonism (see below,
 Section 3.2).
 In his *Reply to Porphyry* Iamblichus establishes a triad of
foundational traditions: the Egyptian, the Chaldaic and the Greek,
represented by the philosophical wisdom of Pythagoras and Plato. The
term "Chaldaic" refers to the *Chaldaean Oracles*
(see above,
 Section 2.2).
 The extant evidence suggests that Plotinus and Porphyry accorded
limited significance to the *Oracles* which, instead, become a
crucial source for Iamblichus: he wrote an extensive commentary on
this work and the revealed Platonizing theology of the
*Oracles* is an integral part of his thought. The Egyptian
tradition is represented by the so-called Hermetic books and,
according to Iamblichus, this is the genuine source of Greek
philosophy (*Reply to Porphyry* I, 2 [SS-2013:
4.7-9]).


### 2.4 Iamblichus' posterity



Iamblichus' philosophical stance is connected to some views
which separate him from Plotinus and Porphyry and lay the ground for
later Neoplatonism, in particular that of Proclus and of the so-called
Athenian school of the fifth and sixth century AD. These views
concern: the status of embodied souls (according to Iamblichus there
is no superior part of our soul which resides in intelligible being);
the role of religious acts revealed by the gods to enable the
soul's ascension to the intelligible realm (as already noted,
for Iamblichus, philosophical and intellectual contemplation alone are
not sufficient and theurgy is necessary); a harmonising account of the
various theological traditions and the privileged role assigned to
Pythagoras and to the *Chaldaean Oracles*; an account of
principles and of the metaphysical hierarchy which, while based on
Plotinus' and Porphyry's doctrines, includes more degrees
and intermediate levels; and, finally, a tendency towards
scholasticism and the systematization of exegetical methods.



A picture of Late Antique philosophy jumping from Iamblichus to
Proclus would however be misleading. Actually, more than one century
separates Iamblichus' death from the foundation of the
Neoplatonist school at Athens by Plutarch of Athens. Some crucial
details escape us: for example, we don't even know how and when
Iamblichus' teaching entered the philosophical schools in Athens
(Goulet 2012). In addition to this, Iamblichus' posterity in the
fourth century does not suggest that his philosophical approach was
immediately and unanimously followed. Praechter (1910) regarded those
disciples of Iamblichus' who settled in Pergamon, gathering
around Iamblichus' student Aedesius, as forming a school (the
"school of Pergamon"), where rational methods were
abandoned in favor of theurgy and religious practices. In addition,
these philosophers are sometimes regarded as forming an ideologically
engaged Pagan group threatened by Christian persecution after
Constantine. Such views are somewhat oversimplistic. Our main source
for reconstructing this phase of Neoplatonism is Eunapius'
*Lives of Philosophers and Sophists* (Goulet 2014). As already
noted, Eunapius is a tendentious source, with his own hagiographical
agenda and with little taste for philosophical technicalities.
Whatever we make of this, he says that Iamblichus' students
formed a large crowd and that those who were eager to learn flocked to
him from all parts (see Eunapius *Lives* VI, 4 [Goulet 2014:
12-14]). This and other passages suggest that Pagan
philosophical teaching definitely did not go underground under and
after Constantine (the elite of the Roman Empire was still largely
Pagan at that time). Eunapius' list of Iamblichus'
students confirms the echo of his teaching: the list includes Sopater
the Syrian (see above,
 Section 1.1),
 Aedesius, Eustathius from Cappadocia, Theodorus, and Euphrasius (see
Eunapius *Lives* V, 5 [Goulet 2014: 12.14-20]). Among
these, Theodorus is likely to coincide with Theodorus of Asine who,
while being a student of Iamblichus, is said to have held different
philosophical views and reverted to an intellectualist Platonism of
the Plotinian sort. Aedesius' school too certainly hosted
different positions and internal debates. Thus Eusebius of Myndus was
a member of that school, but apparently held an attitude closer to
that of Plotinus and he was inclined to reject theurgical and magical
practices. On the other hand, theurgy was adopted by Aedesius'
Iamblichean disciples such as Chrysanthius of Sardis, Maximus of
Ephesus, and Priscus of Thesprotia. Maximus and Priscus were
charismatic figures who are mainly known as masters and counsellors of
the Emperor Julian (Julian studied philosophy at Pergamon around 350).
Iamblichus' teaching actually forms the philosophical background
of Julian's project of restoration of Paganism, as shown by
Julian's own writings (see De Vita 2011) and by the short
treatise *On the Gods and the Cosmos* by one Salustius
(possibly Saturninius Secundus Salutius, a dignitary at Julian's
court). It is worth noting, however, that even committed theurgists
like Maximus did not abandon rational methods (we know about
Maximus' work on Aristotle's *Categories* and
*Prior Analytics*).



In addition to internal debates among Iamblichus' disciples,
fourth-century philosophy includes an overtly anti-Iamblichean trend.
This is the case with Themistius (orator, commentator of Aristotle and
authoritative member of the Senate in Constantinople), who did not
endorse Iamblichus' philosophy and did not show any sympathy for
his theurgic and Pythagorean teaching. He actually sharply criticizes
the new philosophical approach represented by the "man of
Chalcis" (an allusion to Iamblichus: see Themistius,
*Or*. 23, 295b). Themistius engaged in a controversy with
Maximus of Ephesus over Aristotle's logic in Constantinople,
where Julian acted as arbiter (Ammonius, *In Analytica Priora*,
p. 31.11-23). Furthermore, Themistius regarded the Pythagorean
Archytas' treatise on the categories as spurious and argued that
the author was not a Pythagorean at all (Boethius, *In
Categorias*, PL 64, 162 A). By doing so Themistius actually
removed the main support for Iamblichus' Pythagorean and
metaphysical reading of Aristotle. Iamblichus' philosophy, then,
was only gradually accepted and it was regarded with both consensus
and disagreement in its immediate posterity. Certainly,
Iamblichus' philosophical approach did not entail any
abandonment of rational methods, not even among those who
enthusiastically embraced theurgy.


## 3. Iamblichus' System



As a general rule, Iamblichus' system is best characterized as a
refined version of Plotinus'. Building on hierarchical hints
already present in the *Enneads* as well as the work of his own
teacher Porphyry, Iamblichus set about producing a far more complex
picture of reality, while keeping the same fundamental patterns in
place.


### 3.1 The One and the higher principles



Iamblichus' account of the One is difficult to ascertain, since
the crucial testimony (Damascius, *De principiis* II,
1.4-16.19 Combes & Westerink) is somewhat oblique.
What lies beyond doubt is that Iamblichus reacted against
Porphyry's introduction of a first principle
"coordinated" with the Intelligible Triad by positing two
levels above it: on the one hand, a "wholly unspeakable
principle"--which Theodorus of Asine and Damascius
incorporated into their own theology, although Proclus did not: on the
subject, see Linguiti 1988--and, on the other hand, a principle
"uncoordinated with the triad". In this respect,
Iamblichus seems to have wished to distinguish between two almost
contradictory aspects of the first principle: its transcendence with
respect to everything else (negative theology), i.e., absoluteness in
a literal sense; and its causative aspect (cataphatic theology).
Iamblichus, then, appears to have conceived of his "unspeakable
principle" as a safeguard against any objection based on
indefinite regress in the chain of causes, while the principle that is
"uncoordinated to the triad" is akin to Plotinus'
One, insofar as it lies above the Intellect.



Below the One is located the intelligible triad of Limit, the
Unlimited, and the One-Being. This arrangement shows the influence of
Plato's *Philebus* 26C (with the uncoordinated One
as the Cause, and the One-Being as the *mikton*): this is
accounted for in Van Riel 2008. Damascius assimilates this sequence to
another one attributed to "the Pythagoreans":
Monad-Dyad-Triad, and, ultimately, to the system of principles
inferred from the *Chaldean Oracles*: Father-Power-Intellect.
It is likely that the same interpretation was already to be found in
Iamblichus, given that both Pythagoras and the Chaldeans rank high in
his list of authorities.



Whether Iamblichus introduced the doctrine of "henads"
into the teachings of the Neoplatonic School remains controversial
(see Clark 2010; Mesyats 2012; Opsomer in Opsomer et al. 2018:
1365-1366). The henads (literally "unities") are the
very first plurality emanating from the One: since they are located
beyond Being itself, they are meant to bridge the gap between the
absolute One and the intelligible world. Iamblichean authorship of
this theory would make it predate Syrianus and Proclus--its first
explicit proponents--by almost a century, and indeed several
hints point in that direction, in particular the fact that, according
to Proclus, Iamblichus identified "God and the gods" as
the subject of the first hypothesis of Plato's
*Parmenides*. These "gods" might be self-sufficient
items located right below the One and, judging by the--admittedly
very allusive--testimonies of Proclus (references in Saffrey
& Westerink 1968-1997: III, pp. XVII-XXVI) and
Damascius, might indifferently be called "henads" or
"intelligible gods", in contradiction with Syrianus'
and Proclus' later terminological distinctions.



There is also another hint in support of this interpretation.
Damascius explicitly states that according to Iamblichus divinity is
closely correlated to degrees of unity: the intelligible gods are
"crystallised, as it were, around the One" (*De
principiis* II, 36.17). According to this conception, the higher a
god is situated on the scale of reality, the more
"unified" and undifferentiated it is, and the less
accessible to the intellect and to conceptual knowledge: one can only
know such realities by resorting to intuition. This doctrine is hinted
at in various passages of Iamblichus' *Reply to Porphyry*
(where unity, "friendship"--*philia*--and
goodness are all described as fundamental attributes of the gods:
"whatever Being might be in them, this is equivalent to their
unity", I, 19 [SS-2013: 45.8-10]) and is also compatible
with his stressing the fact that knowledge of the gods is innate,
lying as it does within the heart of every individual (I, 3 [SS-2013:
5.14-20]). From an historical point of view, this gradual
diffusion of unity also represents a major contribution to the
representation of reality as a continuum, thereby somewhat bridging
the rift that, following Plotinus, had emerged between the One and the
Intellect. "Unification" too (*henosis*) also
becomes a key philosophical term, and this opens up the possibility of
an anti-intellectual slant, as can be found in a famous extract of the
*Reply to Porphyry* (II, 11 [SS-2013: 73.1-16]).


### 3.2 "Intelligible" and "intellective"



Iamblichus' best-known philosophical doctrine might be the
distinction he introduced between the "intelligible"
(*noeton*) and the "intellective"
(*noeron*). Before Iamblichus, *noeron*--not a very
common word before the second century A.D.--was used to refer to
any thinking entity, and Porphyry employs it mostly in association
with the soul. From Iamblichus onwards, it becomes a technical term
which exclusively designates the order of gods located right below the
Intelligible, and endowed with demiurgic functions. The word is found
with such a meaning in fourth-century authors in the tradition of
Iamblichus, such as the emperor Julian and Salustius.



The idea of distinguishing "seen" and "seeing"
principles (objects and subjects of intellectual knowledge) dates back
to the early interpretation of Plato's *Timaeus (*(39E),
where the Demiurge appears to behold a Model located outside himself
in order to gather from it all the data necessary for the creation of
the Cosmos: Middle Platonists thus used to distinguish between the
Demiurge, Ideas, and Matter. As opposed to, e.g., Longinus (see
Syrianus, *In Metaphysica*, 105.25-28), Plotinus had
decisively argued that intelligibles are actually not to be found
outside the Intellect. Iamblichus instead falls back on more
traditional positions and expressly subordinates the Demiurge to the
Intelligible Model. As, on the other hand, Iamblichus follows
Plotinus' steps in developing a doctrine of the One, this
results in the Demiurge now being assigned a secondary rank, as he is
surpassed by a plethora of other deities, including the Intelligible
Model (*In Timaeum* [D-1973: Fr. 42-46]). He is but the
third member of the "paternal" triad, itself part of a
larger "intellective" Hebdomad (Proclus, *In
Timaeum* I, 308.17-309.13: compare this triad to Fr. 4
[D-1973] *In Philebum* = Damascius, *In Philebum* SS
105). From this point onwards, until the closing of the Neoplatonic
schools, identifying the Demiurge with the First Principle is out of
the question.



On the other hand, Iamblichus fully embraces Plotinus' idea that
intelligibles are endowed with life, power, activity etc. and
therefore multiplicity (at least implicitly). This allows him to
superpose the divine names found in theology (Orpheus, the Chaldeans,
and the dialogues of Plato dealing with the intelligible) upon a
conceptual armature: for instance, the Platonic Demiurge is to be
identified with the Zeus of Hellenic tradition. This effort reveals
itself most conspicuously in Julian, and will find its crowning in
Proclus' *Platonic Theology*. As a general rule, to every
philosophical concept in the intelligible world there corresponds some
divine level or entity: the idea of such a correspondence and its
application to the sequence of predicates present in the hypotheses of
Plato's *Parmenides* is generally assigned to
Proclus' master Syrianus, but several hints suggest that it was
actually introduced by Iamblichus. One explicit instance of such a
term-to-term correspondence is the localization of the genera of Being
within the intellective order rather than the intelligible one,
because of the former's higher degree of multiplicity (Proclus,
*Platonic Theology* I, 52.2-13). This important doctrine
implies that the Demiurgic intellect is now conceived as some kind of
"container" of all intelligible ideas, with the
reservation that it is less unified than the Model is.


### 3.3 Lower entities



Through a comparison between Julian and Proclus (see Lecerf 2012), one
may conclude that Iamblichus had conceived of a variety of Demiurges,
the main one (identified with Zeus) acting as a principle or
"monad" for the others. While Zeus creates the world
insofar as it is governed by rational laws and populated with beings
pertaining to species and genera (themselves of intelligible nature),
other demiurgic entities are tasked with informing matter and bodies
(which undergo a process of generation and corruption) according to
such laws.



Iamblichus already uses the terminology "hypercosmic" vs.
"encosmic" or "pericosmic" (e.g., *Reply to
Porphyry* VIII, 8 [SS-2013: 200.25-27]), inherited from
Middle Platonism but destined to become technical in later
Neoplatonism. In anticipation of this later use, they are meant to
bridge the gap between the Demiurge and the sublunar realm, although
their exact role in Iamblichus remains unclear (the aforementioned
passage speaks of the help they give to souls in their ascent). Such
lower entities seem to be produced according to a geometric
progression (cf. *In Timaeum* [D-1973: Fr. 79]). The
terminological continuity allows one to conceive of Iamblichus'
system as the matrix for later variations, particularly Proclus'
one, although it is to be noted that no text bears witness to the
presence of Proclus' intermediate
"intelligible-intellective" and
"hypercosmic-encosmic" levels in Iamblichus.



The hierarchies of "higher genera" will be considered in
 Section 6.1.


### 3.4 Nature and Matter



Iamblichus' notion of Nature displays little originality when
compared to that of other Neoplatonists. It acts as a productive power
for cosmic beings, originating in the celestial gods (*Reply to
Porphyry* III, 28 [SS-2013: 127.2-12]), but it does not act
according to reason. This ambiguity explains why, depending on the
context, it can be considered either a positive entity, insofar as it
is part of a reality governed by Providence, or a deceitful, almost
evil force, a view strongly influenced by the *Chaldean
Oracles* (see, e.g., V, 18 [SS-2013: 166.18-24]): it comes
as no surprise that, in this respect, Nature is also closely
associated with Fate. The same ambivalence is to be found with regard
to astrology, which Iamblichus deems useful, yet not the best way to
determine the identity of our personal *daimon* (IX,
4-5 [SS-2013: 205.1-207.9]).



Matter also displays both these traits--integration into the
world order and a connection with corporeality and evil.
Iamblichus' *Reply to Porphyry* is replete with allusions
to matter as a taint and source of corruption: "what is mixed
with the irrationality and darkness associated with bodies and matter
is overcome with ignorance" (VI, 4 [SS-2013: 182.7-10]).
By contrast, "divine fire" strives to eradicate
materiality and generation (V, 12 [SS-2013: 161.2]). In such passages,
Iamblichus inherits the strongly negative views on matter developed by
Middle Platonists such as Numenius and further developed by Plotinus.
However, a testimony from John Lydus (*De Mensibus*
175.1-176.7 Wunsch) states, apropos Matter, that
"nothing imperfect stems from the paternal (i.e., demiurgic)
triad". Thus the possibility of a monistic interpretation
remains open: this evidence is studied by Taormina (2016).
Accordingly, several testimonies (e.g., Simplicius, *In
Categorias* 418.3-8) also state that Iamblichus attributed
no real existence to Evil, only a *parhupostasis*.


### 3.5 Overarching concepts and general traits



Iamblichus' work exerted a very profound influence on the
subsequent course of Neoplatonic philosophy. In particular, he stands
out as an important theologian owing to the shift he brought about
with respect to Plotinianism. With Iamblichus, Plotinus'
economical approach to metaphysical principles was developed into
full-fledged metaphysical laws: in this respect, Iamblichus emerges as
a remote forerunner of Medieval scholasticism. He himself vindicated a
"scientific theology" (*Reply to Porphyry* I, 4
[SS-2013: 10.18]) and established a canon of texts that gave it the
justification of tradition.



Perhaps the most conspicuous trait of Iamblichean metaphysics is its
highly vertical conception of causality. For Iamblichus, an effect
does not enjoy any ontological independence with respect to its cause:
anything it adds amounts to failure and nothingness. This idea
predates Iamblichus, but he was the first Pagan philosopher to apply
it with absolute consistency. Most of his system follows from this one
axiom, particularly his doctrine of the soul (see
 Section 6).
 The principles' supervision always lurks in the background:
see, e.g., the idea that the intelligible gods "contain"
the visible gods (i.e., planets; *Reply to Porphyry* I, 19
[SS-2013: 45.14-20]). The idea of the vacuity of effects leads
to the notion that their sole purpose is to render themselves apt to
receive the influx of their causes: Iamblichus calls this
*epitedeiotes,* or "receptivity". This
process of adaptation accounts for most of the diversity in the
phenomenal world. Another important law states that "everything
is in everything according to its property": Damascius ascribes
it to both Iamblichus and Porphyry (*In Philebum* SS 130 =
Iamblichus *In Philebum* [D-1973: Fr. 5]). The last words are
the most important: superior beings keep their prerogatives in spite
of the existence of a universal homology, which means for example that
causes are present to their effects *as causes*, i.e., are not
encompassed by them or relegated to their status. In this way,
Iamblichus manages to preserve at the same time the benefits of divine
immanence (the world is not abandoned by the gods) and the requirement
of divine transcendence, which he feels the need to constantly affirm,
lest he be accused of debasing divinity.



Iamblichus' programme of a scientific theology (see Lecerf
and Taormina forthcoming) is based on newly developed
terminology, of which we have already seen several examples. It also
relies on new structures such as divine orders (*diakosmoi*,
*taxeis*), a notion foreign to Plotinus. Their proliferation
does not bother Iamblichus in the least, since centrifugal tendencies
are curbed by constantly reasserting the fundamental unity of reality.
This is provided for through the return of the same processes in a
more or less absolute form (for instance, what exists in a unified
manner in the universal Paradigm as a whole appears again in
individual paradigms, yet only partially: see *In Timaeum*
[D-1973: Fr. 43]). Recurring metaphysical laws serve the same purpose,
as do schemes such as the regrouping of divine entities in accordance
with meaningful numbers, e.g., triads, a structure that adequately
accounts for uni-multiplicity in reality since it treats as one single
process the succession of an immobile first state
(*mone*), a dynamic procession (*proodos*) and a
return or "conversion" to the first element
(*epistrophe*; see *In Timaeum* [D-1973: Fr. 53]).
Triads are thus a prime example of what modern commentators have named
the "law of mean-terms", i.e., the need for a *tertium
quid* to provide a mediation between two levels. Continuity is
thereby introduced in the picture, although the latter remains
resolutely holistic. The whole stands in relation to its parts as a
cause to its effect: in this sense, it may be said that Iamblichus
created and almost deified the Neoplatonic system as a unified and
coherent account of reality, avoiding any recourse to dualism.


## 4. Pythagoreanism, Mathematics


### 4.1 Limit and the Unlimited



As we have seen, Iamblichus posited at the top of his system, below
the One but above the Intelligible--and thus at a supra-essential
level--the dual principles of Limit (*peras*) and the
Unlimited (or Infinite: *apeiron*). These principles belong to
the Pythagorean tradition (see, e.g., Philolaus Fr. 1 Huffman and
Nicomachus, *Introduction to Arithmetic* II, 18, 4), although
the main catalysts responsible for their integration into the
Neoplatonic system were two indirect accounts, Plato's
*Philebus* (see above,
 Section 3.1)
 and Aristotle, *Metaphysics* A, 5 (987a15-19):



> 
> 
> (the Pythagoreans) thought that finitude and infinity were not
> attributes of certain other things, e.g., of fire or earth or anything
> else of this kind, but that infinity itself and unity itself were the
> substance of the things of which they are predicated (trans.
> Ross).
> 
> 
> 



Closer to Iamblichus, one must also mention the precedent of Eudorus
of Alexandria (*apud* Simplicius, *In Phys*.
118.22-28), as well as Plotinus' acknowledgment of
something *apeiron* within the Intellect (*Ennead* II, 4
[12]).



The importance of this Pythagoreanizing slant can hardly be
overstated. In agreement with Iamblichus' vertical conception of
reality, it means that everything below this dyad is to be regarded as
a mix of determination and indetermination: and this includes gods, as
well as Forms such as those contained within the Model, some of which
are claimed to partake in movement and alterity (see *In
Timaeum* [D-1973: Fr. 46]), while less elaborate versions of
Platonism would rather view them as solely determinate, viz.
thinkable. In a text from Simplicius' commentary on the
*Categories* (135.10-16 [DL-1972: Fr. 37]), the
productive capacity of the One appears to reflect these two
dimensions:



> 
> 
> Since the power of the One, from which all quantity is generated, is
> extended unchanged ... and gives definition to each thing as it
> proceeds from itself, in that it pervades the whole in an entirely
> undivided manner, it brings the continuous into being, by making its
> progression single and uninterrupted ...: but in that it comes to
> a halt in its progression at each of the forms and defines each
> ... it brings about the discrete (trans. Fleet).
> 
> 
> 



Consequently, Iamblichus came to the conclusion that all things
partake in opposition, a phenomenon most conspicuous in the sublunary
world, as the philosopher notes in the context of an allegorical
exegesis of the prologue to Plato's *Timaeus* (*In
Timaeum* [D-1973: Fr. 10]). Thus, it appears that
Iamblichus' goal in introducing the Limit-Unlimited pair
was to account for the genesis of multiplicity and alterity, Limit
providing definition and intelligibility, while the Unlimited enables
infinite flux and iteration within all individual items partaking of
the same form: this interpretation is, at any rate, in line with the
*epitedeiotes* or "receptivity" axiom
(see
 Section 3.5
 above), which states that the effect receives the causal influx
according to what it is itself, and thus always imperfectly. This may
be seen as Iamblichus' equivalent of Plotinus'
intellectual vitalism (the notion that the intelligible world is
intrinsically active, being Life itself): it allows for considerable
metaphysical dynamism. To be sure, Limit retains axiological
precedence over the Unlimited, but indetermination can no longer be
conceived of as a mere by-product of matter's resistance to
form. Rather, while it is true that higher principles are more
characterized by Limit and lower ones by the Unlimited, each and every
thing reflects, to some extent, both of these principles.


### 4.2 Mathematics



Limit and the Unlimited are also principles active among mathematical
entities (*On General Mathematical Science*, chap. 13). Here
they play a role similar to that of the pairs Monad and Dyad, Odd and
Even, or Same and Other according to Nicomachus of Gerasa, the
neo-Pythagorean author of the *Introduction to Arithmetic* and
one of Iamblichus' intellectual heroes; similar pairs studied by
the mathematical sciences are "continuous" and
"discrete" (*sunekhes*, *diorismenon*),
"magnitude" and "plurality"
(*megethos*, *plethos*: cf. Nicomachus,
*Intr*. *arith*. I, 2, 4-5), all of which concur
to form a dynamic picture of reality. The four mathematical
sciences--arithmetic, which takes precedence over the others;
geometry, music and astronomy--each study a corresponding kind of
being, and were the object of *On Pythagoreanism* vol. IV and
VIII-X respectively (see the plan of the work as outlined by
O'Meara 1989).



Iamblichus' interest in mathematics is part of a larger trend
that includes authors such as Theon of Smyrna and Calcidius, but
excludes Plotinus and, to a lesser extent, Porphyry. For Iamblichus,
mathematics is both a scientific discipline and concerns a realm of
being, intermediate between the intelligible and the sensible: the
latter view is influenced by Aristotelian ontology as well as by the
Platonic analogy of the Line (*Republic*, 509d-511e), but
with the Pythagorean proviso that mathematical entities "exist
in themselves" and that each number possesses a distinct
essence.



The study of mathematics allows the soul to disengage itself from the
material world, thus providing a starting point towards higher being.
More interestingly, mathematics is assigned symbolic significance in a
variety of fields: vol. V-VII of *On Pythagoreanism* (now
lost) dealt with the mathematical teachings that can be drawn
concerning ethics, physics and theology respectively (the anonymous
*Theologoumena arithmeticae* might provide some insight into
Iamblichus' view of the relation between arithmetic and
theology, as they include extensive quotes from Nicomachus as well as
Iamblichus' first teacher Anatolius). Mathematics is therefore
versatile and multivalent in its essence (see, e.g., *On General
Mathematical Science*, chap. 15; 18), and thus closely associated
with the soul (*ibid*., chap. 9). It is also very likely that
Syrianus' distinction of various types of
"number"--in descending order: eidetic, mathematical,
physical, cf., e.g., *In Metaphysica*
122.11-16--stems from Iamblichean teachings.



Iamblichus' writings on mathematics were influential, and are
used, e.g., in Syrianus' commentary on the *Metaphysics*
and Proclus' commentary on Euclid. His views on the
*quadrivium*, drawing upon Nicomachus, were also adopted by
Martianus Capella and Boethius, and through them became an integral
part of education in the Middle Ages.


### 4.3 Iamblichus and Pythagoreanism



While Iamblichus took great pains to study mathematics in detail, its
true meaning, according to him, is not of a "technical"
nature: rather, it is meant to constitute a form of philosophical
ascesis:



> 
> 
> If we intend to practice mathematics in a Pythagorean manner, it is
> necessary to pursue with zeal its divinely inspired, elevating,
> purifying and perfective way. (*On General Mathematical
> Science*, chap. 22)
> 
> 
> 



Indeed, as part of his *sumphonia* programme, Iamblichus
strove to fully integrate Pythagorean teaching into the Hellenic
dogmatic tradition, making Pythagoras the recipient of a divine
revelation handed down by Orpheus through a mysterious
figure, "Aglaophamus" (*De Vita
Pythagorica* 146). Book II of *On Pythagoreanism*, the
*Protrepticus*, while using a variety of sources, also taps
into the Pythagorean repertoire with wisdom texts such as the
*Golden Verses*. Building on the then widely accepted axiom
that the truth had already been revealed in remote times and then
merely reformulated--if not twisted--by recent writers, he
accepted as authoritative the pseudo-Pythagorean corpus for which he
(along with Stobaeus, who knew the Iamblichean *oeuvre*
quite well) is one of our main sources: on Iamblichus' library
of Pythagorean texts, see Macris 2002. Iamblichus made the most
conspicuous use of these texts in his lost *Commentary on the*
Categories, where ps.-Archytas' *On the All* was
repeatedly quoted as the source of the Aristotelian treatise (see
below,
 Section 5.1).



In order to assess Iamblichus' reliability as a witness of
ancient Pythagoreanism, one has to take into account a variety of
factors, including his attitude towards the information available to
him (ranging from literal dependence to creative elaboration for his
own ideological and systematic purposes). This is crucial, since the
*Pythagorean Life* in particular is one of our major sources on
this subject (for details, see the studies collected in Huffman 2014;
von Albrecht et al. 2002).


## 5. Logic and the Categories


### 5.1 Iamblichus' commentary work on Aristotle



Iamblichus wrote an extensive commentary on the *Categories*,
fragments of which have been preserved by Simplicius and Dexippus (a
student of Iamblichus): in addition to literal quotes, Iamblichus is
behind much of Simplicius' extant exegesis of this treatise. We
also have evidence that Iamblichus wrote a commentary on
Aristotle's *Prior Analytics* and we know about his
exegetical work on the *De interpretatione* and the *De
caelo* (see Opsomer 2015). From the first century BC onwards,
Platonist philosophers had been familiar with Aristotle's
*Categories*: Platonists such as Eudorus of Alexandria and
Nicostratus raised objections against Aristotle's doctrine;
Plotinus wrote a very important treatise *On the Genera of
Being,* where he critically discussed Aristotle's categories
(*Ennead* VI, 1-3). To the best of our knowledge,
however, no Platonist wrote a commentary on Aristotle's
*Categories* before Porphyry, who was the author of two
commentaries on this treatise: a short and extant elucidation in a
question-and-answer format and a very extensive commentary in seven
books dedicated to someone called Gedalius, which is now lost. In
addition, Porphyry wrote an introduction to logic, the
*Isagoge*, which is closely connected to the
*Categories*. With Porphyry, then, Aristotle's
*Categories* became an integral part of the Platonist
curriculum and this was a crucial move for the subsequent history of
Late Antique and medieval philosophy. As is often the case,
Iamblichus' exegetical work relies on Porphyry but introduces
some changes which are probably aimed to supplement (and possibly
supplant) Porphyry's approach. Simplicius informs us that
Iamblichus followed the great and now lost commentary written by
Porphyry, while adding two distinctive features. First Iamblichus
"applied his Intellective Theory (*noera theoria*)
everywhere, to almost all of the chapter-headings" (Simplicius,
*In Categorias*, 2.13-15 [DL-1972: Fr. 2], trans. Chase;
see Dillon 1997). Iamblichus employs the same expression, *noera
theoria* in the opening section of the *Reply to
Porphyry* (I, 2 [SS-2013: 4.16]), in a passage where he
characterizes the mode of inquiry that is typical of theology.
Secondly, Iamblichus took Archytas' treatise *On the All*
to be Aristotle's source and he developed a thoroughly
Pythagorising interpretation of the *Categories* (Simplicius,
*In Categorias*, 2.15-25 [DL-1972: Fr. 2]; see Hoffmann
1980). Archytas' treatise is actually a forgery which scholars
now date to the first century BC. Iamblichus, however, took it to be a
genuine work by Archytas and in doing so he claimed a Pythagorean
origin for Aristotle's theory. To sum up, Iamblichus'
exegesis of the *Categories* was an integral part of his
Pythagorean philosophical programme and in interpreting the
*Categories* Iamblichus made use of his metaphysical and
theological views. Apparently, Iamblichus pushed his reading of
Aristotle along Platonic/Pythagorean lines so far that (as later
sources report) he did not refrain from assuming that Aristotle was
not opposed to Plato on the theory of Ideas (see Elias/David, *In
Categorias*, 123.2-3).


### 5.2 The Pythagorean reading of the *Categories*



Iamblichus' interpretation characteristically included a
definition of the "target" (*skopos*) of
Aristotle's treatise, which Iamblichus regarded as focusing on
signifying expressions insofar as they signify things via concepts
(see Hoffmann 1987). This view was not new and Simplicius traces it
back to the previous tradition starting from the early Peripatetic
commentators (Simplicius, *In Categorias*, 13.15-18).
Iamblichus, however, added two distinctive features. First, he gave a
more systematic account of the target of Aristotle's treatise
(for example, Porphyry too claimed that Aristotle's
*Categories* focus on simple signifying expressions insofar as
they signify things, but to the best of our knowledge he did not refer
to concepts). In addition to this, Iamblichus' discussion of
semantics incorporated a Neoplatonist account of language and
signification grounded in Neoplatonic metaphysics and psychology
(Simplicius, *In Categorias*, 12.16-13.12: see Griffin
2012). Iamblichus referred to analogy (*analogia*) as a
resource that explains how Aristotle's account of categories can
be applied to intelligible beings too. For example, Simplicius reports
that according to Iamblichus the property of being receptive of
contraries while being one and the same in number (see Arist.,
*Cat.*, 5, 4a10-11) applies to all levels of substance
(both sensible and intelligible) via analogy (*kata analogian*,
Simpl., *In Categorias*, 116.25-26 [DL-1972: Fr. 33]): in
intelligible substance contraries belong to substance simultaneously
whereas in sensible substance they exist successively. Accordingly,
different levels of being reveal corresponding structures (where lower
degrees in the hierarchy entail increasing multiplicity and
dispersion). This metaphysical framework accounts for
Iamblichus' views about genera and predication. Iamblichus is
critical of the previous Peripatetic tradition: he criticizes
Alexander of Aphrodisias for mistakenly regarding corporeal and
incorporeal beings as species ranked under the same genus (that of
substance, *ousia*) (Simplicius, *In Categorias*,
83.20-23 [DL-1972: Fr. 24]). Iamblichus' point is that the
Peripatetic reading of the *Categories* does not account for
the hierarchical structure of reality. On Iamblichus' view, full
weight should instead be given to the hierarchical notion of the genus
as a unity of derivation from a principle (actually the genus is both
the principle itself and the hierarchy of items depending on it). This
structure does not entail that levels ranked in the same genus share
any common item. Rather, different and hierarchically ordered levels
are connected via analogy, so that lower items mirror higher ones
while not sharing any common item with them. Analogy, then, allows
Iamblichus to combine two complementary aspects of his metaphysics: on
the one hand the vertical hierarchy that separates different levels of
beings, on the other hand the continuity that connects these different
levels together within a unified whole. Iamblichus' approach
emerges in his account of essential or synonymous predication (the
predication of items within the same category). Porphyry argued that
in this kind of predication subject and predicate denote two different
items, the *akatakakton* (uncoordinated or unallocated) and the
*katatetagmenon* (coordinated or allocated) (Simplicius, *In
Categorias*, 53.6-9; 79.24-30). The meaning of these
expressions is debated. The "allocated genus" is to be
identified with the *in re* universal shared by particulars;
the unallocated may be either the separated and Platonic *ante
rem* universal or the abstracted and *post rem* universal
concept. Whatever we make of Porphyry's view, Iamblichus started
from Porphyry's exegesis and gave a different slant to it (see
Chiaradonna 2023: 138-162). In doing so Iamblichus suggested
that Aristotle's essential predication is a way of expressing
the participation of corporeal beings in their transcendent genera
(Simplicius, *In Categorias*, 53.9-18 [DL-1972: Fr. 16]).
More precisely, "Socrates is man" would be a way of
expressing the fact that the corporeal Socrates participates in the
transcendent Form of Man. Separate genera provide the basis for
essential predication, though they are not properly predicated in
themselves (what is predicated is rather the participated item).
Interestingly, Iamblichus refers to the technical notion of
*ptosis* ("case"), which is associated with
Aristotle's account of paronymy in the *Categories*: a
*ptosis* is an inflected form of a term (such as
"grammatical" or "courageous") which is
paronymous with the noun form and derives from it
("grammatical" and "courageous" are both
adjectival forms which derive from "grammar" and
"courage" respectively). So Iamblichus held that in the
predicative statement "Socrates is man", "man"
improperly occurs in the predication instead of its
*ptosis*: Iamblichus is probably referring here to an
adjectival construction like "human". Such a paronymous
form would correctly refer to the participation of Socrates in his
transcendent Form. Simplicius informs us too that Iamblichus focused
on Aristotle's account of motion and activity: Plotinus had
criticized Aristotle for not regarding motion as a single category and
had argued that motion in sensible beings is a form of complete
activity (Simplicius, *In Categorias*, 303.35-306.12
[DL-1972: Fr. 86]). Iamblichus rejects Plotinus' account and
aims to integrate Aristotle's account of sensible motion as
"incomplete actuality" into a Platonist philosophical
framework (see Taormina 1999: chap. III).


### 5.3 Categories and theology



Iamblichus' exegesis of the *Categories* (in particular
his account of genera of hierarchical structures and his use of
analogy) sheds light on other areas of his philosophy and forms the
background of Iamblichus' criticism of Porphyry's account
of divine hierarchy in the *Reply to Porphyry* (see Chiaradonna
2023: 138-162). There Iamblichus rejects Porphyry's
account of divine hierarchy as misleading, since Porphyry regarded
classes of divine beings as species ranked under the same genus and
determined by "properties" (*idiomata*) that
act as specific differentiae (*Reply to Porphyry*, I, 4
[SS-2013: 7.21-8.6]). In so doing, Porphyry ruins the very idea
of hierarchy: *divine* comes to be a common genus which is
predicated of all of its species, in the same way as *animal*
is predicated of (say) *horse* and *dog*. Against
Porphyry, Iamblichus calls for a qualified use of logical notions
which makes the hierarchical relation between different classes of
divine beings clear. Each level differs from the others as a whole and
not in the same way as different species are divided under the same
common genus. As said above, in his interpretation of the
*Categories* Iamblichus argued that the genus is a hierarchical
relation in which items from different levels are analogically
connected to their origin. This can be set in parallel with what
Iamblichus says in the *Reply to Porphyry*:



> 
> 
> But if one were to apply an analogical principle of identity to
> different genera, for example to the many genera of gods, and again to
> those among the demons and heroes, and lastly in the case of souls,
> then one might succeed in defining their specific characteristics.
> (*Reply to Porphyry*, I, 4 [SS-2013: 10.25-11.4], trans.
> CDH-2003)
> 
> 
> 


## 6. The Soul, Theurgy and Religion


### 6.1 The soul's place in the system



According to Iamblichus, "soul" is but the last and
weakest link in the chain of "higher genera"
(*kreittona gene*). In the *Reply to Porphyry*,
those entities are enumerated in full:
gods--archangels--angels--demons--heroes--archons
ruling the world--enmattered archons--souls. This is a token
of Iamblichus' receptiveness towards the religious speculation
of his day, although most of this theological bestiary was in fact
already present in Porphyry's *Letter to Anebo*.
Iamblichus' acceptance of "evil demons" (cf.
O'Neill 2018) is particularly interesting, since it seems to
undermine Iamblichus' monism and providentialism, and is best
explained as reflecting the influence of the *Chaldean
Oracles*.



In contradistinction with the gods, the soul receives a plethora of
negative traits: it is imperfect, intermittent, it leans towards
matter; and while the causes of Order and Beauty exist in full
communion with the gods, the soul can never be given more than a mere
share of it (*Reply to Porphyry* I, 6-7 [SS-2013:
15.14-17.7]). The immutability of this celestial hierarchy is
striking, and foreshadows the later works of Hierocles, Proclus, and
pseudo-Dionysius the Areopagite. Although the soul's
versatility--its ability to "make use of varied forms and
life-principles"--allows it to attach itself to superior
beings and lay claim "to receiving perfection as an angelic,
immaculate soul" (*Reply to Porphyry* II, 2 [SS-2013:
51.10-52.11]), on closer reading it appears to be unable to
escape its condition by virtue of its own essence: its ascent is never
complete (it is an endeavor, *ephesis* or
*henosis*, with a suffix expressing verbal action) and it
presupposes, moreover, the gods' "goodwill and
illumination". Porphyry had previously drawn a similar
distinction between demons that are so "by essence"
(*kat' ousian*) or by mere "relation"
(*kata skhesin*), the latter being those humans who, by virtue
of their excellent life, are allotted demonic status. On the other
hand, the human soul is also unable to be relegated to the rank of
animals via metempsychosis (cf. the title of one of Iamblichus'
psychological works preserved by Nemesius of Emesa, *On the Nature
of Man*, chap. 2, p. 35.7-11 Morani). Some points, however,
remain unclear, such as how exactly Iamblichus' generic
distinction between human souls and "divine" ones would
fit within such a structure; or what we are to make of the souls of
exceptional, even semi-divine characters such as Pythagoras or the
theurgists. Similar preoccupations underlie Frs. 82 and 83 *In
Timaeum* [D-1973], interpreting *Timaeus* 41d.



Lastly and perhaps most importantly, the soul is irremediably inferior
to the *intellect*. Rejecting any internalist interpretation of
intellectual processes, Iamblichus regards them as the result of the
soul's illumination by a transcendent entity. Our information on
this matter is to be gathered mostly from the late Aristotelian
commentators, pseudo-Simplicius (see *In De anima*
313.1-10, with a reference to the "unparticipated"
intellect which, if genuinely Iamblichean, would predate Proclean
terminology) and Priscian of Lydia (*Metaphrasis in
Theophrastum*): these relatively neglected texts are the object of
the pioneering work Steel 1978. Indeed, such a position implies some
knowledge of the philosophical debates on this issue within the
Aristotelian tradition (Theophrastus, Alexander). Its significance is
enormous, insofar as it directly leads to the rejection of
Plotinus' doctrine of the undescended soul: that is, the idea
that something of the soul always remains in the intelligible world.
Thus, rejecting the notion that the soul shares *homeomereia*
with the remaining intellectual entities, Iamblichus writes:



> 
> 
> the doctrine opposed to this separates soul, insofar as it is born
> second with regard to the intellect as a distinct hypostasis, and
> interprets what, in it, partakes of intellect as something dependent
> from intellect, although it is susceptible of individual existence;
> and it separates it from all the higher genera. (*De anima*,
> sect. 7 [DF-2002])
> 
> 
> 



Iamblichus also fiercely attacks Plotinus (as well as Theodorus of
Asine) for the assumption that "there is something in us that is
impassible and always thinking" (*In Timaeum* [D-1973:
Fr. 87]; on this text see Rist 1975 and Dillon 2005). However, here
again the attitude of the superior souls with regard to their descent
is somewhat obscure: according to Damascius (*In Parm*. IV,
24.1-7 Combes & Westerink), Iamblichus taught that
the first class of souls "descends while not descending",
and that the descent "only effects a presence alongside what is
here". This problem was tackled by van den Berg (1997; opting
for the existence of unaffected pure souls and thus positing
Iamblichus as an intermediary between Plotinus and Proclus) and
Taormina (2012; emphasizing that every soul remains separated from the
intelligible and only relates to it through participation). It is, in
any case, clear that Iamblichus conceived of the soul's presence
in this world as something natural and normal, not as a transitory
exile, even less as "always an evil" (the theory of
Cronius, Numenius and Harpocration, criticized in *De anima*
sect. 29 [DF-2002]).


### 6.2 Soul and embodiment



It is fair to say that Iamblichus--in this respect closer to
Porphyry--focuses more closely than Plotinus on the soul's
indwelling within the body and on the actions it performs alongside
it. In what remains of his treatise *On the Soul*, he reviews
all sorts of historical theses about the composition, powers and
activities of the soul, and does not hesitate to engage his
Neoplatonic predecessors.



In the available testimonies (Priscian in particular: see the
assessment in Huby 1993), the soul is constantly associated with the
notion of "life". The latter is approached here not so
much as an essential psychic property (as had been the case in the
*Phaedo*), as in terms of the corporeal
"life-principles" (*zoai*, most often in the
plural) that the soul is said to project outside of itself in order to
get a hold on the external world:



> 
> 
> insofar as it puts forth other levels of life that incline towards
> generation and consort with the body, thus far (soul) is involved in
> the order of the cosmos (*Letter to Macedonius*, *apud*
> Stobaeus, *Anthology* II, 8, 45 [DP-2009: 25]).
> 
> 
> 



In this manner, psychic activities that involve a relationship with
external objects (such as sense-perception) presuppose a dialectic
relationship between the soul's essence and the multiplicity of
powers it deploys: the individual and immaterial entity
"soul" goes out of itself to grasp enmattered items,
before going back (literally "converting",
*epistrephein*) in order to compare the data thus aggregated to
(stable) Forms, which lend it intelligibility. As a result,



> 
> 
> the particular soul, as being in the middle of all the kinds of things
> of this world, and being divided together with them and being
> multiplied along with them, not only remains but also changes, living
> through so many partial lives. And not only with regard to its
> dispositions, but also with regard to its substance it changes
> somewhat. (Priscian, *Metaphrasis* 32.15-19 [trans. Huby
> 1993: 8])
> 
> 
> 



Imagination, being torn between sensibility and abstract intellection,
whose difference it helps bridge, functions in a similar way and
contributes to making the soul the median entity *par
excellence*.



Sensibility, then, would seem to be proof of the soul's radical
inability to remain in itself, as opposed to the intellect, which is
immobile and in actuality by its own nature (another sign of the fact
that the unity of the soul is no longer considered self-evident is the
introduction of the so-called "vehicle" of the soul, a
spiritual garment that acts as an interface between the soul and
bodies: on this subject, cf. Finamore 1985). What stands out as most
remarkable is the notion that the soul's essence is also
challenged in the course of sensitive acts. Iamblichus here inherits
the Aristotelian terminology of Essence/Substance
(*ousia*)--Power (*dynamis*)--Activity
(*energeia*) (see LCH-2022): a single essence--say,
the human soul--acts as a substratum for a plurality of powers
(sensitive, intellective, imaginative, etc.), and those powers are in
turn actualized in a greater plurality of activities
(sense-perception, *aisthesis*, of *x*, *y*,
or *z*; intellection, *noesis*, about *x*,
*y*, or *z*). These three terms are hierarchised,
insofar as the soul can remain inactive: but in Aristotle, this
hierarchy remains largely implicit, contrary to Iamblichus and his
unequivocal conception of vertical causality (see above,
 Section 3.5).
 In applying his own principles, Iamblichus argues that, since the
effect is nothing outside of its cause, any flaw connatural to the
effect would also have to be preassumed in the cause. Since, then, the
soul's *activities* show instability and imperfection,
this inability to act consistently and permanently points to a break
in its very *essence* (cf. *De anima* sect. C [DF-2002]
= pseudo-Simplicius, *In De anima* 89.33-35).



This is Iamblichus' notion of the "changing self",
as first expounded by Steel 1978. Such a conception of the human soul
represents a major break in the Platonic tradition, which until then
had been prone to emphasize the soul's inner dignity and
divinity: on the other hand, it is a very convenient way to account
for human fallibility. One could interpret it as a literal exegesis of
*Timaeus* 35A: the Demiurge creates the soul's essence as
a mix of indivisible and divisible Being, so that--one might
think--it is no more indivisible than it is divisible. By the
same reasoning, Iamblichus concludes that the soul is at the same time
changing and unchanging, dying and undying. This, at least, is what
characterizes "particular" souls (*merikai* or
*en merei*: a terminology propagated by Iamblichus--see
*Reply to Porphyry* V, 2 [SS-2013: 149.26]--before it
became usual in later authors). The case of divine souls is less
clear-cut, since they are able to mend the gap between essence and
activity (*De anima* sect. 20-21; see also 18). It is
unclear whether--and how--this picture can be reconciled
with Iamblichus' allusions to "two souls", one
originating in the intelligible, the other given to us by celestial
influences (*Reply to Porphyry* VIII, 6 [SS-2013:
199.1-12]).


### 6.3 Soul's ascent and salvation; religion



Belittled as it is in the grand scheme of things, and unable to
achieve any perpetual union with the intelligible world, the human
soul is deemed connatural to "nothingness" (*Reply to
Porphyry* III, 18 [SS-2013: 108.16-17]). It now needs
external help from the gods--that is, *grace*--in
order to perform any relevant action. Broken in its *essence*,
it is, however, able to regain some ground through its
*activity*. Co-action with the gods, "godlike
action" (*theourgia*, i.e., theurgy), is the purpose of
the Iamblichean soul, which it attains through religious acts such as
prayer, offerings, sacrifice, etc., that is the very liturgy that
Porphyry had attacked in the *Letter to Anebo*. Hence the
necessary connection between two fields, psychology and the philosophy
of religion, which was clearly set out by Shaw (1995). Ritual is given
precedence over philosophical ascesis or discursive thinking, although
Iamblichus would say that he is merely giving philosophy its due place
rather than abolishing it: it is also true that he underlines the need
for the religious practitioner to be virtuous, individual sanctity
being a requisite to make the medium apt to receive the gods'
influx. But Iamblichus heavily stresses that the key to the whole
process always lies in the gods: very interestingly,
"human", "artificial" or "natural"
contributions are equally side-lined and relegated to the status of
mere auxiliary causes (see, e.g., *Reply to Porphyry* III, 9
[SS-2013: 89.7-9]). He is also adamant about the human inability
to extort any effect from the higher beings (i.e., via
"magic"), since they are by nature impassible.



It remains beyond doubt that his stance on the matter is
anti-intellectualist in nature and thus in stark contrast with the
teachings of Plotinus and Porphyry. One does not start with
self-knowledge, as Porphyry had set out to demonstrate in a treatise
*On the phrase: "Know thyself",* which he had
dedicated to Iamblichus, no doubt cognizant of all the implications of
this (Fr. 273 Smith = Stobaeus, *Anthology* III, 21, 26).
Instead, knowledge of the gods encompasses self-knowledge (*Reply
to Porphyry* X, 1 [SS-2013: 212.2-3]) and should be taken as
the correct starting-point. What remains intellectualistic in
Iamblichus' approach is the conviction that not acting in the
light of theological knowledge leads to the failure of the ritual
process (*ibid.* II, 10 [SS-2013: 68.25-69.20]).
Accordingly, the best theurgist is also the best theologian: and since
Iamblichus' theology is highly philosophical in nature, insofar
as it strives to identify the Pagan gods with metaphysical forces or
concepts and submits them to the authority of the Platonic One, it
seems necessary that, in Iamblichus' system, precedence be given
to Neoplatonist religious specialists deriving their information from
the appropriate literature. In this respect, theurgy represents a
rationalization of the irrational, rather than the converse. It is
also important to note that the conflict between the
Plotino-Porphyrian approach and Iamblichus' one does not simply
amount to a conflict between philosophy and religion; rather, it
opposes two different modes of access to the divine, with
Iamblichus' predecessors laying emphasis on silent ascesis and
the shedding of our external identity, and accordingly viewing
corporeality and materiality as something inherently negative.



According to Iamblichus, the gods help mankind overcome its inherent
weakness by revealing symbols to them that will establish some sort of
connection: one of the criticisms he lays on Porphyry is that his
views will "leave earth deprived of the presence of the superior
beings" (*Reply to Porphyry* I, 8 [SS-2013:
21.12-13]; on related issues concerning Porphyry's
and Iamblichus' contrasting views on dreams and divination, see
Timotin [2022] 109-126). These symbols may differ in nature:
items, rituals, myths, theological revelations such as the
*Chaldean Oracles*, etc.; and most of them are placed under the
patronage of a particular deity, thus creating a "chain"
(*seira*) of, say, sun-like entities. In this manner,
Iamblichean ontology necessarily leads to cultural traditionalism; it
also opens up the possibility of a grandiose *sumphonia*
of all Pagan schools or currents, be they Hellenic or
"barbarian", the latter actually being assigned even more
prestige insofar as the Egyptians, Assyrians, Phoenicians etc. enjoy
greater antiquity and--supposedly--avoided innovation,
contrary to the Greeks (*Reply to Porphyry* VII, 5 [SS-2013:
192.22-24]). A whole new field thus opened up for Platonists in
which they could exercise their exegetical virtuosity in search of
remarkable analogies. It is no wonder, then, that Iamblichus'
views were heartily embraced by later proponents of a "Pagan
revival", of whom the most prominent was Julian the Apostate: a
Roman emperor as well as the pupil of Maximus of Ephesus, who was a
philosopher in the tradition of Iamblichus in addition to being the
most infamous theurgist of his time.


## 7. Ethics and Politics


### 7.1 Neoplatonism and politics



Neoplatonism has often been regarded as a theological and
other-worldly philosophy which assigns little (if any) significance to
politics and conceives of ethics merely as an ascetic path for the
separation of the soul from the body. This view has been questioned by
D.J. O'Meara and the significance of Neoplatonist political
philosophy is gaining increasing attention (see O'Meara 2003;
Schramm 2013). Iamblichus wrote a whole treatise *On virtues*,
which is lost but whose content can be inferred from later sources. In
addition to this, references to ethics and politics can be gathered
from his extant works, especially the letters preserved by Johannes
Stobaeus (see DP-2009; TP-2010). It is a notable fact that some of
Iamblichus' interlocutors were influential figures in the
fourth-century Roman empire, as is for example the case with Sopater
of Apamea (see above,
 Section 1.1).
 It is somewhat difficult to clearly grasp Iamblichus' position
on these issues, since his treatise on virtues is lost, the later
testimonia are cursory and Iamblichus' letters are for the most
part introductory and refrain from philosophical technicalities.



The extant evidence nonetheless suffices to outline some of
Iamblichus' views. Two letters focus on providence, fate and
free will against the background of Iamblichus' account of
causation, which sees the One as the principle of all being and the
lower levels of reality as characterized by increasing degrees of
multiplicity (see the letters to Macedonius and Sopater: Johannes
Stobaeus I, 5, 17 and I, 5, 18). Iamblichus identifies the sphere of
operation of fate with nature, i.e., "the immanent causal
principle of the cosmos and that which immanently comprises the
totality of causes of the realm of generation" (DP-2009: 35).
These views are reminiscent of the Stoic deterministic model of
causation, but Iamblichus also emphasises that the soul contains
within itself a free and independent life and is able to emancipate
itself from worldly influences (see Johannes Stobaeus I, 8, 45a).



This theological and metaphysical framework also grounds
Iamblichus' views about politics. In his letters he describes
the art of rulership as a kind of divinisation based on wisdom:
through wisdom human beings are assimilated to gods and political
rulership is an image of divine rulership in cosmos (see Johannes
Stobaeus III, 3, 26). Leadership is connected with philanthropy, which
makes the ruler mild, pleasant and approachable. Such views outline a
characteristically theocratic conception. Elsewhere, however,
Iamblichus suggests a more modest view about rulership: he emphasises
the importance of law, which he sees as the genuine expression of a
divine model, the ruler being only its guardian (see Johannes Stobaeus
IV, 5, 77). Such views can certainly be traced back to Plato: the
passages about kingship can be set in parallel with Plato's
account of philosopher-kings in the *Republic*, whereas those
about the primacy of laws obviously recall Plato's political
views in the *Laws*. But parallels are abundant even outside
the Platonist tradition (e.g., in Stoicism and in Dio Chrysostomus, in
the Pseudo-Pythagorean writings) and the introductory tone of
Iamblichus' letters makes it difficult to isolate characteristic
Neoplatonist elements. According to some interpreters, however,
Iamblichus' interest in politics is likely to be connected to
his views about the embodied soul. As O'Meara remarks,



> 
> 
> Human soul, alienated from its divine origins, finds its identity in
> its relation to body. As a consequence, the material, bodily aspects
> of the human condition were to be of much greater relevance for the
> divinization of soul in later Neoplatonism than in Plotinus. (2003:
> 39)
> 
> 
> 



In fact, Neoplatonist philosophical ideas shaped not only
Iamblichus' views about politics, but also those of the Emperor
Julian, whose Neoplatonist background (ultimately deriving from the
Iamblichean teaching of his masters at Pergamon) informs both his
account of law and rulership (see Julian's *Letter to
Themistius*) and his theological foundation of the Roman Empire
(Elm 2012).


### 7.2 The hierarchy of virtues



In *Ennead* I, 2, Plotinus holds that virtues bearing the same
names (that is the four cardinal virtues of Plato's
*Republic*: wisdom, temperance, courage and justice) exist in
different grades at different levels: the lower level is that of the
so-called civic or political virtues, whereas the higher degrees
include the soul's purification and the result of it, that is
the contemplation of Intellect on the part of the soul. In
*Sentence* 32, Porphyry draws on Plotinus and offers a
classification of virtues: these are divided into civic, purificatory,
contemplative and paradigmatic virtues. Iamblichus' lost
treatise *On virtues* was certainly based on these previous
discussions and offered a systematic discussion that laid the ground
for later Neoplatonist accounts of the so-called *scala
virtutum*. The late anonymous *Prolegomena to Plato's
philosophy* ascribes the distinction of five levels of virtues to
Iamblichus: natural, moral, political, purificatory, and contemplative
(see *Prolegomena* SS 26.30-36). This distinction is
connected to the order or reading of Plato's dialogues: thus the
*Gorgias* focuses on the political virtues, the *Phaedo*
on the purificatory. All this is most likely to derive from
Iamblichus, who then associated his canon of twelve Platonic dialogues
with the different levels of the *scala virtutum* (see above,
 Section 2.2).
 While crucial, the testimony of the *Prolegomena* is
nonetheless partial: we know from Damascius and Marinus of Neapolis
that Iamblichus' distinction had two further levels at the top:
those of "paradigmatic" and "theurgic" or
"hieratic" virtues. Iamblichus, therefore, probably
distinguished seven levels of virtues: natural, moral, political,
purificatory, contemplative, paradigmatic, theurgic or hieratic. The
views about the soul and theurgy outlined above help explain why
Iamblichus, unlike Plotinus and Porphyry, posited theurgic or hieratic
virtues at the top of his classification: such virtues are the highest
degree of the soul's ascension to the divine, which human beings
cannot achieve merely through their intellect.



It is worth noting that the author of the *Prolegomena* sets
out the hierarchy of virtues as an order "according to
depth" (*kata bathos*). The term *bathos* has a
technical meaning in Iamblichus: it is borrowed from mathematics and
is opposed to *platos* insofar as it describes the vertical
order of items in a hierarchy, as opposed to the horizontal one (see
Taormina in TP-2010: 245). This suggests that Iamblichus arranged his
classification of virtues according to the vertical pattern described
above, which points to his distinctive account of the hierarchy of
beings.