1. SN: 13004458 1
How does Dante’s use of optical theory influence his moral vision in the Commedia?
‘Within the profound and shining subsistence
of the lofty Light appeared to me three
circles of three colors and one magnitude; and
one seemed reflected by the other, as rainbow
by rainbow, and the third seemed fire
breathed forth equally from the one and the other.’1
(Par. XXXIII, 115-21)
Dante Alighieri (1265-1321) was undeniably an eclectic thinker; in particular, the
Commedia exemplifies his wide scope of learned knowledge, encompassing a
heterogeneous range of sources from scripture, medieval and classical philosophy, and,
importantly, optical theory, all of which coalesce to reciprocate Dante’s moral vision. The
above quote represents the point at which the temperature of the poem is at its highest, as
Dante the pilgrim nears the climax of his spiritual journey, coming face-to-face with the
Trinity of God, a visual spectacle, that un-coincidentally is carefully crafted by Dante
through a trinity of synergistic optical ideas: reflection, rainbow, and colour.
Consequently, optical theory occupied an exalted position in Dante’s thought, however,
Dante was no professional philosopher; instead, the Bible was Dante’s chief source.
Therefore, Dante did not directly use optical theories; rather, he vulgarized these complex
scientific ideas, in conjunction with scripture and the literary technique of ‘synaesthesia’
to convey the moral journey of Dante the pilgrim.
For contemporaries, ‘optical theory’ was understood as hypotheses about the source,
properties, transmission, and reception of light. In medieval Europe, from the thirteenth-
century onwards there was a deeply ingrained ‘light-metaphysics’ tradition of
philosopher-theologians who sought to reconcile the properties of light within a religious
context, known collectively as the ‘perspectivae’. To precisely operationalize ‘moral
vision’, the best source is Dante himself. The Epistle to Cangrande della Scala is useful
for this purpose, and whilst caution should be taken that the letter was written during
Dante’s exile from Florence and the language of comparing his ‘friendship’ with
1
D. Alighieri, Paradiso, tran. C. S. Singleton (Princeton: Princeton University Press,
1991), p.379. All citations are taken from the Singleton editions.

2. SN: 13004458 2
Cangrande to that of God and man masks a blatant appeal for patronage, the source
provides a unique insight into Dante’s own definition of ‘moral vision’. Dante
writes that the purpose of the Commedia ‘is to remove those in this life living in a state of
misery, and bring them to a state of happiness.’2
In lieu with the tradition of medieval
treatises to correct faults and improve one-self, Dante clarifies that the philosophical core
of the Commedia is that of morals and ethics.3
Likewise, he states that the Commedia will
follow the poetic convention of the comedy genre, because ‘at the beginning it is horrible
and foul, as being Hell; but at the close it is happy, desirable, and pleasing, as being
Paradise.’4
Thus, for Dante, ‘moral vision’ closely mirrors his own personal crisis of
faith during his exile, personified through Dante the pilgrim, who himself experiences a
spiritual crisis in canto I of Inferno,being ‘lost in a dark wood’5
; yet, by the final canto of
Paradiso, all desire (the source of imperfection) has been vanquished, and Dante is
reunited with God in perfect harmony, ‘like a wheel/ that is evenly moved, by the Love
which/ moves the sun and the other stars.’6
The term “Light-metaphysics” (lichtmetaphysik) was coined in the twentieth-century by
German historian Clemens Baeumker (1853-1924) to account for the shared interest in
light-studies in the thirteenth-century.7
Since, there has been a proliferation in medieval
studies of optics; in particular, D. Lindberg, K. Tachau, and R. Southern have provided
insightful overviews of general perspectivistae theories, in addition to particular
perspectivists such as William of Ockham and Robert Grosseteste. However, as art
historian G. Rosser has observed, light-metaphysics in the Commedia have ‘tended to be
treated by Dante professionals as a subject in their own right, calling either for
recognition of their inconsistency or for their ultimate harmonization [with Dante’s
theology].’8
First to comprehensively explore Dante’s light-metaphysics was B. Nardi’s
collection of essays Saggi di filosofia dantesca,which identified the Neoplatonic idea of
emanation as key to Dante’s view of the universe as the creation of divine light. Yet,
Nardi strayed too close to arguing that Dante was a ‘scientist’ fully versed in medieval
2 D. Alighieri, Epistle to Cangrande della Scala,in P. Toynbee, Dantis Alighierii
Epistolae (Oxford: Clarendon Press, 1967), p.202.
3
Ibid, p.202.
4
Ibid, p.201.
5
Inferno. I,2-3, p.3.
6
Par. XXXIII, 143-145, p.381.
7
See C. Baeumker, ‘Witelo, ein Philosoph und Naturforscher des XIII. Jahrhunderts’,
Beiträge, Vol 3. No. 2 (1908).
8
G. Rosser, ‘Beyond Naturalism in Art and Poetry’, Art History, Vol. 34, No. 3 (June,
2012), p. 483.

3. SN: 13004458 3
optical thought. In retaliation, D. Lindberg, A. Cornish, J. A. Mazzeo, and S. Gilson, all
proponents of what has become the orthodox approach, advocate a more sceptical view of
the connection between Dante and optical theories. Whilst Mazzeo’s Medieval Cultural
Tradition is useful as a background, the most systematic study of Dante’s thought is
Gilson’s Medieval Optics. Gilson’s aim to reassess the role of light in Dante’s Commedia
is grandiose, arguing that the umbrella term ‘light-metaphysics’ is inadequate, as it has
encouraged scholars ‘to oversimplify the complexity and heterogeneity of medieval ideas
about light.’9
Whilst D. Lindberg has been the only historian to suggest a solution to this
problem, by fencing the study of light into four compartmentalised areas; epistemology,
theology, physics and metaphysics10; for Gilson, Lindberg’s classifications are artificial
and do not solve the problem, but rather creates an additional one by treating categories
of light in isolation from one another, a methodology binary opposed to medieval writers,
who integrated ‘light with religious beliefs, scientific concerns, and philosophical
doctrines in divergent ways to produce complex results.’11
Instead, Gilson outlines a
persuasive case that ‘rather than specific authors, Dante relies on more general ideas
which he rethinks, and syncretically lends with other sources.’12
This approach, in which
Dante is assimilating and simplifying many diverse optical theories is shared by Cornish,
who states that Dante ‘is “vulgarizing”… he is rendering the concepts and language of
natural sciences useful.’13
Neither is optics an isolated example of Dante’s
‘vulgarization’, because as Cornish observes in his astronomy, ‘Dante rarely invokes
arcane terminology and grossly simplifies the complex apparatus of medieval
astronomical theory.’14
The vulgarisation thesis when fused with Dante poetry has great coherence as a
methodology, because Dante was not primarily concerned with abstract theological ideas,
rather, he wanted to share his knowledge more widely, and break down the barriers of
Scholasticism. This theme is present early in Dante’s works as in the Convivio Dante
writes, ‘knowledge is the ultimate perfection of our soul, in which lies our ultimate
9 S. Gilson, Medieval Optics and Theories of Light in the Works of Dante (Lampter:
Edwin Mellen Press, 2000), p.151.
10
D. Lindberg, Theories of Vision from Al-Kindi to Kepler (Chicago: University of
Chicago Press, 1996), p.95-99.
11
S. Gilson, Medieval Optics, p.157.
12
Ibid, p.169.
13
A. Cornish, ‘Vulgarizing Science: Vernacular Translation of Natural Philosophy’,
Dante for the New Millenium, ed. T. Barolini (New York: Fordham University Press,
2003), p.171.
14
A. Cornish, Reading Dante’s Stars (New Haven: Yale University Press, 2000), p.8.

4. SN: 13004458 4
happiness.’15
Hence, this is largely why Dante wrote the Commedia in the vernacular as
opposed to Latin, in order to reach a wider audience. Therefore, the Commedia did not
simply seek to replicate previous works such as Brunetto Latini’s Tresor, a medieval
encyclopaedia divorced from all personal flair; instead, Dante was concerned with the
widespread purification of ethics and morals. For this reason, P. Shaw argues the
Commedia features a plethora of popes who ‘fail in their role as spiritual guides’ and
‘secular rulers who are motivated by naked ambition and greed’16, all concrete examples
of injustice, and imbued with Dante’s own thoughts and feelings which made the
Commedia so powerful. Therefore, demonstrating how light-metaphysics best interacts
with the purpose, genre, and moral vision of the Commedia, Gilson and Cornish’s
vulgarization thesis offers the most persuasive analysis to-date. However, its main
limitation is its tendency to ignore the centrality of the Bible, and how sight interacts with
other senses: hearing, smell, taste and touch. For a more complete synthesis, this essay
will interweave the twin-methodologies of ‘vulgarization’ and ‘synaesthesia’, the
linguistic portrayal of the senses. I will first outline the problems with medieval optical
theory; second, explore the cultural tradition of light-metaphysics; and thirdly, I will
argue the Commedia features a gradualistic increasing of light which produces a blinding
effect on Dante the pilgrim, the growing severity of this blindness being directly
proportional to Dante’s stadial ascension through Purgatory and Paradise, each act of
blindness a stepping-stone, of which increases Dante’s knowledge, and desire to be
reunited with God.
Any study of optics must confront several interconnected problems and questions with
the sources. Most problematic is what knowledge of light-metaphysics Dante possessed?
As suggested, Dante employed a ‘pick and mix’ approach, appropriating ideas not from a
single corpus of knowledge, but from a wide range of secondary sources. Whilst Dante
undoubtedly shows remarkable sensitivity as poet and philosopher to contemporary
optical ideas, as Gilson has observed, ‘it is extremely difficult to prove that Dante based
this conception of vision on the perspectivae’.17
Second, is there any direct evidence of
optical theories in the Commedia? Yes, however any attempt at intellectual history, trying
to trace the diffusion of specific theories across time and space is a notoriously difficult
task, particularly as many medieval philosophers had contradictory and heterodox sets of
15
D. Alighieri, Convivio, tr. Richard Lansing, accessed via the Princeton Dante Project,
I, I, §I.
16
P. Shaw, Reading Dante: From Here to Eternity (New York: Liveright, 2013), p.43.
17
S. Gilson, Medieval Optics, p.91.

5. SN: 13004458 5
ideas, ideas which were constantly subject to revision; and most never fully ordered their
ideas about light into a systematic body of doctrines. And finally, it is difficult to gauge
what branch of perspectivist knowledge is being appropriated and to what effect:
Reflection? Refraction? Colour? Rainbows?
Importantly, Dante was born during a time in which optics were assimilated with
Christian doctrine. As Lindberg has observed, optical treatises were part of the statutory
curricula from the thirteenth-century onwards. In fact, it was widely acknowledged that
visuality lay ‘not at the periphery but at the nexus of natural philosophy and
epistemology, all ultimately at the service of theology.’18 In medieval scholastic doctrine,
optics and semantics were deeply interlinked because the senses were seen as ‘not merely
gateways to the intellect, but lower forms in a continuous hierarchy of faculties of
knowing, unified by light.’19
In particular, the sense of sight occupied an exalted status
over the other senses as the eyes possessed a certain ‘purity and subtlety about the entities
associated with them, notably fire (sight’s ‘element’), light, and colour, and as
consequence had nobility attached to their objects.’20
The connection of sight with fire has classical origins with Plato’s Timaeus, in which
Plato outlined an ‘extramissive model’ of vision as a light ray emitted from the eye which
coalesced with the external fire of the atmosphere.21
Hence, Platonic models represented
‘seeing’ as an extension of touch, as the notion of a ‘visual stream of internal fire
‘striking’ and ‘pressing against’ the external object offers a tactile model of visual
perception.22
Platonic ideas gained influence in medieval Christendom precisely because
they were malleable to orthodox doctrine, allowing thinkers such as Augustine, who had a
Manichean background, to give light pre-eminence in conceiving the divine. By contrast,
Aristotle’s ‘intromission model’ outlined in De anima, the idea that light rays were
received through the eye where the image was chemically constructed in the brain took
much longer to diffuse into Christian doctrine. Most modern writers take for granted the
impact of Aristotle in medieval Western Europe, praising him as mere lip service to
18
K. Tachau, Vision and Certitude in the Age of Ockham (Leiden: E.J. Brill Publishing,
1988), xvi.
19
J. A. Mazzeo, Medieval Cultural Tradition in Dante’s Comedy (New York: Greenwood
Press, 1968), p.82.
20
S. Clark, Vanities of the Eye, (Oxford: Oxford University Press, 2007), p. 10.
21
M. J. Huxtable, The Relationship of Light and Colour in Medieval Thought and
Imagination’, On Light, ed. K. P. Clarke and S. Baccianti (Medium Aevum, 2014), p.27.
22
Ibid, p.27.

6. SN: 13004458 6
medieval theology. However as Scott and Huxtable both show, ‘Aristotle’s writings were
virtually unknown in the Latin West until the late twelfth-century’23
, as Aristotle did not
arrive in an accessible Latin translation until James of Venice’s c.1150 edition, as well as
the fact that in contrast to Neoplatonism, Aristotle seemed the ‘more suspicious, and
potentially corrupting pagan writer.’24
However, by the time of Dante’s birth in 1265, approximately fifty-five of Aristotle’s
works had been translated into Latin, and Aristotelian ideas possessed popular appeal.25
Throughout the entire corpus of Dante’s works there exists a clear relationship between
light and God. In the Convivio, Dante sets out his foundational metaphysical ideas of
light, how divine light descends upon all things, ordering and maintaining them: ‘the
divine goodness descends into all things, for otherwise they could not exist. But it is
received diversely, in greater or lesser measure, by those things which receive it.’26
For
Dante, the differing amount of divine light that reaches each individual is why human
beings are so different in character. Early on, Dante assimilated both Neoplatinism and
Aristotlelianism, in what Mazzeo refers to as an ‘inconsistent blend, fusing emanationism
with a notion of creation; which described the Good as outflowing in one great
outpouring, and yet identifies it with Being and a first cause that remains transcendent
over what it produces.’27
This blending of Neoplatonism and Aristotlelianism is best associated with Albertus
Magnus, who perceived divine light as filtering down from the Empyrean, in a hierarchy
of gradually decreasing luminosity, the further away it reached. In fact, Dante directly
cites Albertus in the Convivio stating: ‘We see the Sun’s light, derived from one source,
received diversely by diverse bodies, as Albert says in his book On the Intellect.’28
Clearly, Dante viewed the world as operating on two levels of hierarchy, as ‘there are
others which, because they are entirely transparent, not only receive the light but do not
impede, but rather transmit it to other things.’29
For Dante, creatures share in differing
degrees of divine goodness, ranging from the ‘pure “luminousness” of the angels down to
23
J. A. Scott, Understanding Dante (Notre Dame: University of Notre Dame Press,
2005), p.108.
24
Huxtable, Light and Colour, p.34.
25
Ibid, p. 231.
26
Convivio, III, vii, §2-3.
27
Mazzeo, Medieval Cultural Tradition, p.92.
28
Convivio, III, vii, §2.
29
Ibid, III, viii, §iv.

7. SN: 13004458 7
man, who is, metaphorically speaking, partially visible.’30
Therefore, angels, being closer
to God receive divine light directly, and all other beings receive it indirectly as a
reflection.
By the Commedia, Dante’s light-metaphysics had reached their full maturity. Again, the
Epistle is useful to flesh out these ideas, as nowhere in the Commedia does Dante overtly
state the philosophers he has read. In the Epistle, Dante makes an impressive sixteen
citations to eight classical/medieval philosophers, including: Aristotle, Plato, Cicero,
Augustine, Pseudo-Dionysius, Richard of St. Victor, Bernard and Boëtius. In particular,
Aristotle is hailed as the philosopher par excellence, referred to simply as ‘the
Philosopher’31
, and cited no less than six times.32
However, Dante’s optical knowledge
must also be offset against the scriptural, as he also makes a total of fourteen biblical
citations from eight books: Wisdom, Psalms, Ecclesiastics, Ezekiel, Corinthians,
Matthew, Daniel and John. Whilst this quantitative analysis is of limited use in itself, it
does highlight that for approximately each optical citation, there is a biblical equivalent
(16 optical: 14 biblical); and whilst not representative of the Commedia in general, it
shows that Dante thought of the optical in relation to the spiritual. More telling, is that
scripture and optics are used to reciprocate one another as Dante repeatedly states that if
the bible is not enough ‘let them read Richard of St. Victor… let them read Bernard… let
them read Augustine.’33
In fact, the sheer length of the scriptural citations in the latter
section of the letter implies that Dante gave more superiority to the biblical, than the
optical.
Therefore, the Epistle shows that Dante’s Commedia is fusing religious and optical ideas
together, one deeply interlinked with astronomy. Dante’s Aristotelian and Ptolemaic view
of the nine heavens in the Commedia is one governed by motion. As Dante writes,
‘Everything, then, which has motion is in some respect defective, and has not its whole
being complete.’34
For Dante, all motion, as in the Aristotelian universe, is a ‘symptom of
incompleteness, of the “desire” to become fully actual and to be assimilated to the Pure
30
Mazzeo, Medieval Cultural Tradition, p.93.
31
Epistle, p.198, §5.
32
Ibid, for Aristotle see §5 p.198, §16 p.202, §18 p.203, §20 p.205, §25 p.207, §27 p.
208.
33
Ibid, p.209, §28.
34
Ibid, p.207 §26.

8. SN: 13004458 8
Act which moves the world as an object of desire.’35
Hence, only the Empyrean heaven,
being God ‘has no need of motion for its perfection.’36
In Dante’s view, the primum
mobile has the swiftest movement out of the heavens, a rotation that is caused by its
desire to be reunited to the heaven above it, the Empyrean heaven, which is completely
immobile and still.
The connection between light and moral vision is a theme that runs throughout the
Commedia. As Mazzeo observes, the poem is a carefully ordered hierarchy of lights and
shadows, which allows Dante to structure his journey from material to divine light.37
This
hierarchy is particularly evident in the progression that Dante the pilgrim experiences in
his journey through Inferno where there is an absence of light, to Paradiso where light is
ubiquitous. In canto V of Inferno,Dante the pilgrim describes his own blindness at being
in a ‘place mute of all light’.38
This ‘blindness’ is both physical and metaphorical, as
Dante is physically unable to see, being underground, but darkness is also used for poetic
effect to show Dante’s moral lack of faith. As Cambon has shown, the senses are crucial
in Dante’s perception of the divine, as light and harmonious sounds depict Divine Love,
whereas darkness and harsh sounds are the opposite.39
Hence, whilst Dante’s sense of
sight is weakened, his other senses are heightened, in particular his sense of hearing, as
hell is likened to bellowing ‘like the sea in tempest when it is assailed by warring
winds.’40
The transition from the darkness and ‘dead air that afflicted my eyes…’ of the Inferno to
the ‘Sweet hue of oriental sapphire’ and ‘serene face of the sky, pure even to the first
circle’; which restores ‘delight’ to Dante’s eyes in the opening canto of Paradiso marks a
shift in tone of the poem, to one of progress, rather than punishment.41
Purgatory is
distinct from Hell as it works on a contrapasso system (counter-suffering), borrowed
from Aristotle who advocated repayment in kind for a malicious action, and more
obviously, maxims from the Old Testament which teach “an eye for eye, tooth for
tooth…” (Exod. 21. 24-25) Thus, the purpose of Purgatory is to vanquish the stains of sin,
35
Mazzeo, Medieval Cultural Tradition, p.96.
36
Epistle, p.207, §26.
37
Mazzeo, Medieval Cultural Tradition, p.56.
38
Inferno. V,p. 27, p.49.
39
G. Cambon, ‘Synaesthesia in the Divine Comedy’, Dante Studies, No. 88 (March,
1970), p. 3.
40
Inferno. V, 28-30, p.49.
41
Par. I, 12-18, p. 3.

9. SN: 13004458 9
not punish. A more optimistic tone conveyed through light and beauty, because as Dante
emerges from the Earth to the night sky above Mount Purgatory, this is the first showing
of real light in the Commedia so far.42
For this stage of the journey, Virgil remains with
Dante but ‘as more of a companion than a guide. The real guide is the light of the sun and
its movement around the earth.’43
Thus, as Dante progresses throughout the Purgatorio
and Paradiso he is subject to repeated ‘bedazzling’, and even blindness as he gets closer
to the Empyrean heaven. As Gilson has observed, ‘all of the scenes of dazzling and
blinding in the final two cantiche can be related to a gradualistic process by which, as
Dante ascends, the intensity of natural and supernatural light sources increases and so
does his ability to withstand them.’44 In Purgatorio XV, Virgil reassures Dante that by
the end of his journey the intensity of the light will become completely attuned to his
senses. Virgil exclaims that the divine light ‘is a messenger that comes to invite to the/
ascent. Soon will it be that that the seeing of/ these will not be hard for you, but as great a
delight…’45
However, not everything in the Purgatorio involves blinding, rather, in most
examples Dante’s visual senses gets overloaded temporarily, a phenomenon Dante refers
to as “soverchio”, meaning ‘excessive’ or ‘immoderate’. This is evident when the suns
light dazes Dante to the extent that he is forced to raise his arms to protect himself: ‘I
lifted my hands above my eyebrows and made for me the shade that lessens excess of
light.’46
Here Dante conforms to the Aristotelian idea that overstimulation of a specific
sense destroys, or damages it irreversibly. In De anima, Aristotle states that ‘anything
excessively shrill or deep destroys the hearing: and the same in flavours destroys the
taste, and in colours, the sight, whether the excessively brilliant or the dark…’47
For
Dante, conveying this hyper-sensualisation is incredibly important, as the senses are our
only way of experiencing reality, and hence, they are tangible ways of showing God,
which is an incorporeal being, and beyond human conception.
In Paradiso, Dante begins his ascent with Beatrice as his guide to heaven ‘when all the
hemisphere there was white, and the other dark.’48
Hence, whereas it is midnight in
Jerusalem, it is noon in the earthly paradise. As Singleton notes, the chronology is
42
S. Ralphs, Dante’s Journey to the Centre: Some Patterns in his Allegory (Manchester:
Manchester University Press, 1972), p.22.
43
Ibid, p.25.
44
Gilson, Medieval Optics, p.79.
45
Purg. XV, 30-34, p.157.
46
Purg. XV,13-15, p.155.
47
Aristotle, De Anima III §II, in Gilson, Medieval Optics, p.81.
48
Par. I, 42-43, p.5.

10. SN: 13004458 10
deliberately calculated as the entrance into the Inferno takes place in the evening,
Purgatory at dawn, and Paradise at high noon. This for Dante is richly symbolic, noon
being the point at which the suns light is most harsh, exaggerated by the canto beginning
with an invocation addressed to Apollo, god of the sun.49
From now on, there is to be no
more darkness, rather a progression from light to light. Vulgarization can be seen in
action when Dante ascends to the heaven of the sun in canto XII. Here, Dante describes a
double rainbow: ‘two bows, parallel and like in colour, bend across a/ thin cloud when
Juno gives the order to her/ handmaid… whom love consumed as the sun does/ vapors-
and make the people here presage,/ by reason of the covenant that God made/ with
Noah.’50 This is an example of a triple simile assimilating optical theory, classics, and
theology in one. Dante did not believe in the refraction of light, rather, he subscribed to
the Aristotelian belief that the second rainbow was a reflection of the first. Here, Juno’s
‘handmaid’ Iris, daughter of Thaumas is a character borrowed from Ovid’s
Metamorphoses, and generally regarded as the personification of the rainbow, ‘which was
regarded as the messenger of the gods of Juno in particular.’51
Finally, the reference to the
‘covenant that God made with Noah’ is a biblical allusion to Noah’s Ark, and God’s
promise not to flood the world again. However, rainbows possessed deeper significance
for Dante, as the books of Revelations and Ezekiel are responsible for much of his
rainbow imagery, as several passages present the rainbow as a symbol of divine power.
For example, in Revelations 4: 2-4 God is seated on a throne that ‘had the appearance of
jasper and ruby’ and ‘a rainbow that shone like an emerald encircled the throne.’ As M.
Kempshall has shown in his study of Gregory the Great, sight was connected with
wisdom and kingship, and Gregory paid close attention to the gemstones mentioned in
Ezekiel, Isaiah and Revelation, as precious stones were a symbol of those in the Church
strong in faith and love.52
Indeed, colour too was Christianised; in particular, jasper, a
shade of green, mentioned above alongside rubies as forming the throne of God
symbolised ‘the minds of those who teach in the Church’.53 Dante himself possessed an
extensive knowledge of the Bible and therefore would have been acutely aware of the
importance of colour connotations as an expression of the divine.
49
C. S. Singleton, Paradiso: Commentary (Princeton: Princeton University Press, 1975),
p.15.
50
Par. XII, 8-18, p.129.
51
Singleton, Paradiso: Commentary, p.207.
52
M. Kempshall, ‘No Bishop, No King: The Ministerial Ideology of Kingship and
Asser’s Res Gestae Aelfredi’, p.127.
53
Ibid, p.126.

11. SN: 13004458 11
Dante’s blinding’s become increasingly more frequent as he ascends through each
heaven, and with each blinding Dante’s sight becomes rehabilitated, a process which is a
form of “visual tempering” to prepare Dante to witness the light of God. This tempering
is evident in Paradiso XXI when Beatrice refrains from smiling lest the sheer beauty of
her smile destroy Dante. Beatrice exclaims that “Were I to smile… you would become
such as was Semele when she was turned to ashes.’54
Yet, two cantos later, Dante’s vision
has become sufficiently tempered by hash light to be able to see Beatrice’s face, which
surpassing all corporeal beauty, is ‘all aflame.’55
However, as is common, when Dante
sight strengthens, his capacity to speak becomes overwhelmed, as ‘he can frame no
word’, as all speech is stunned by Beatrice’s beauty.
The longest period of blindness Dante experiences in Paradise is when he blinds himself
by looking at St. John, an act likened to staring directly at a solar eclipse.56
For eighty-
nine lines Dante remains blinded, and it is only in the next canto that Beatrice finally
restores his vision by emitting an extramissive ray transmitted from her eyes: ‘Beatrice
chased away every/ mote from my eyes with the radiance of her/ own, which shone more
than a thousand miles.’57
This clearly exemplifies the Neoplatonic influence in Dante’s
optical knowledge. However, as seen before, the optical is fused with the biblical, as the
restoration of Dante’s sight is conveyed through Pauline similes, which compare Dante’s
dazzling’s to that of St. Paul’s blindness in Acts 9: 17-18, who too is blinded by the
divine light of Jesus. The comparison of Beatrice to Ananias of Damascus, the disciple
sent by Christ to cure St. Paul’s blindness is deeply symbolic, as St. John says that
Beatrice ‘has in her look the power/ which the hand of Ananias had.’58
Thus, Dante, like
Paul who too was faithless and lost, once his blindness is cured, his sight is described as
‘reformed’, being able to ‘see better than before’, a palpable statement of his progress
towards God.59
These repeated blinding’s should be seen as the preparation for Dante’s
reunification with God. As L. Pertile astutely suggests, the driving force in Paradise is
“desire”, the desire for Dante to be reunited with God. Hence, Dante’s increasing
knowledge is revealed to the reader through ‘an increment of his ability to withstand and
54
Par. XXI, 4-24, p.233.
55
Ibid. XXIII, 22-24, p.259.
56
Ibid, XXV, 117-122, p.287.
57
Ibid, XXVI, 75-78, p.293.
58
Ibid, XXVI, 10-12, p.289.
59
Ibid, XXVI, 79, p.295.

12. SN: 13004458 12
penetrate that light.’60
This desire is manifested sensually, as the pilgrim greedily drinks
from the river of pure light in Paradiso XXX, his hunger for God propelling him to drink
more ravenously than any ‘infant, [who] on waking, so suddenly rushes with face forward
towards the milk.’61
Here the verb ‘to see’ (vedere) is repeated a total of eighteen times62
,
but more significantly the senses seem fused, for Dante drinks light and sees odour’s, a
process that Mazzeo refers to as ‘mystical synaesthesia’.63
Indeed, the river is a sensory
spectacle as ‘living sparks’ erupt from it, and drop onto the ‘blossoms, like rubies set in
gold.’64
Hence, the assimilation of the heightened level of sensitivity to his sensory
stimuli, the simile of breastfeeding, and his baptism in a river of light all symbolise that
‘Dante has been reborn, having become a child once more.’65 As Dante exclaims, the
river gives him ‘new vision’, so that ‘there is no light so bright that my eyes could not
have withstood it.’66
Spiritually, Dante has been reborn in preparation for his rendezvous
with God.
Finally, returning to Paradiso XXXIII, we can see vulgarization and desire playing out to
their fullest extent, as the temperature of the poem reaches its epic conclusion. Ironically,
it is in the final canto where Dante is closest in proximity to God that ‘he is no longer
blinded by the light. Quite the opposite. If he did not see the divine light he would be
blinded.’67
This is evident when St. Bernard signals Dante should look upwards, but
Dante exclaims ‘I was already of myself such as he wished68
, showing how Dante has
overcome his need for a guide and his moral journey is nearly at an end. By now Dante
can see clearly, his eyes becoming transhumanised69
as by gazing at God’s light his sight
is ‘becoming/ pure, was entering more and more through/ the beam of the lofty Light
which in itself is true.’70 Dante has to walk through a beam of pure light to find the source
of God, a difficult task, as he is unable to recount what he saw in great detail due to
complete overstimulation of his sight, which overpowers all other senses. As Dante
60
L. Pertile, “Paradiso”: A Drama of Desire”, Word and Drama in Dante: Essays on the
Divina Commedia (Dublin: Irish Academic Press, 1993), p.165.
61 Par. XXX, 82-85, p.341.
62 Ibid, See lines 9, 13, 15, 29, 43, 45, 47, 58, 81, 95, 97, 99, 102, 110, 118, 130 and 131.
63
Mazzeo, Medieval Cultural Tradition, p.123.
64
Ibid, XXX, 64-66, p.339.
65
Mazzeo, Medieval Cultural Tradition, p.123.
66
D. Alighieri, Par. XXX, 60-61, p. 339.
67
Gilson, Medieval Optics, p.89.
68
Par. XXXIII, 50-51.
69
Gilson, Medieval Optics, p.103.
70
Par. XXXIII, 51-51, p.375

13. SN: 13004458 13
laments, ‘Now will my speech fall more short… than that of an infant who still bathes his
tongue at the breast.’71
As with Paradiso XXX, Dante the poet manipulates taste, speech
and light, drawing again on baby imagery to express that words, a human construct, are
artificial, and are mere ‘baby-talk’ in contrast to God, a perfect being unexplainable using
flawed human language. However, when Dante finally sees God, He is a geometric shape,
three circles of light; and like Dante’s Aristotelian rainbow in Paradiso VII, each is a
reflection of the other ‘as rainbow by rainbow’, conveying an image reminiscent of
Joachim of Fiore’s Borromean rings in the Liber Figurarum, rather than a human
likeness.72
In fact, this image of God is the third and last rainbow simile in the Paradiso,
and the penultimate simile of the Commedia; and as suggested in the introduction,
contained within it is a nexus of optical and biblical ideas. Clearly, Dante’s decision to
represent divine power as rainbow-like was drawing on scriptural evidence, in particular
Ezekiel 1: 28, in which the ‘rainbow in the clouds on a rainy day… was the appearance of
the likeness of the Lord.’ Likewise, the Son as the reflection of the Father, and the Spirit
‘breathed forth’ from both is no coincidence, as in Hebrews 1: 3 the Son is ‘the exact
representation of His being’, and the Council of Nicea had used similar light imagery to
assert the non-inferiority of Christ. As Singleton has observed, the three ‘giri’ are not
motionless, but spinning in contrast to the rest of the Empyrean which is motionless,
symbolizing the complete actualisation of intellection and perfection.73
This correlates to
Wisdom 7: 24-28 in which wisdom is ‘more mobile than any motion’, and ‘a reflection of
eternal light, a spotless mirror in the working of God.’ Hence, for Dante, the Trinity as
conveyed through reflection, rainbow and geometric circular imagery conveys the
perfection of God; a being devoid of desire and defectiveness, one that the pilgrim is
harmonised with by lastly becoming a wheel revolving around God. In essence, Dante is
transformed from a state of imperfection in Inferno,to a state of wisdom, all-
knowingness, perfection and total completion by the final lines of the poem, a
transformation heavily facilitated by optical ideas.
So, how does Dante’s use of optical theory influence his moral vision? As my selective
examples have shown, Dante is not simply translating optical theories, rather, he is
vulgarizing. Whilst Dante demonstrates remarkable sensitivity to optical ideas, often,
optical ideas provide a useful foundation, one that Dante can then manipulate using poetic
71
Par. XXXIII, 105-108, p.377.
72
Ibid, XXXIII, 118, p.379.
73
Singleton, Paradiso: Commentary, p.582.

14. SN: 13004458 14
skill and artistry to assimilate with other sources such as classical philosophy, and most
commonly, the Bible. Unsurprisingly, optical ideas have such prevalence in the
Commedia because of their dominance in Christian doctrine, a status that provided Dante
with a range of widely relatable images about light. In particular, the supra-temporal
quality of light meant that light was nearest analogy to God in a sub-lunar world as light’s
connection with knowledge. Hence, whilst Dante uses optical doctrines related to
reflection, rainbows and colour extensively, he picks and mixes his sources with a
considerable degree of selectivity and freedom. Ultimately, these scientific ideas are fully
at the service of conveying the moral and spiritual transformation of Dante the pilgrim.

15. SN: 13004458 15
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