[doi 10.1515%2fsemi.2001.099] l. miccoli -- two thirteenth-century theories of light- robert...

Two thirteenth-century theories of light:Robert Grosseteste and St. Bonaventure

LUCIA MICCOLI

As the good is in the intelligible region to reason and the objects of reason, so isthis in the visible world to vision and the objects of vision. _ [W]hen the eyes areno longer turned upon objects upon whose colours the light of day falls but that of

the dim luminaries of night, their edge is blunted and they appear almost blind, asif pure vision did not dwell in them. _ But when, I take it, they are directed uponobjects illumined by the sun, they see clearly, and vision appears to reside in these

same eyes._ Apply this comparison to the soul also in this way. When it is firmlyfixed on the domain where truth and reality shine resplendent it apprehends andknows them and appears to possess reason; but when it inclines to that region

which is mingled with darkness, the world of becoming and passing away, it opinesonly and its edge is blunted, and it shifts its opinions hither and thither, and againseems as if it lacked reason. _ This reality, then, that gives their truth to theobjects of knowledge and the power of knowing to the knower, you must say isthe idea of good, and you must conceive it as being the cause of knowledge, andof truth in so far as known. _ The sun, I presume you will say, not only furnishesto visibles the power of visibility but it also provides for their generation and

growth and nurture though it is not itself generation. _ In like manner, then, youare to say that objects of knowledge not only receive from the presence of the goodtheir being known, but their very existence and essence is derived to them from it,

though the good itself is not essence but still transcends essence in dignity andsurpassing power. (Plato VI, 508b509b, Eng. trans Plato 1970: 103107)

And God said, Let there be light, and there was light. (Genesis 1: 3)

Your light and your truth shine on. (Psalms 42: 3)

You are dressed in glory and splendor, you are covered in light like a cloak.

(Psalms 103: 12)

In the beginning was the Word, and the Word was with God, and the Word was

God. He was with God in the beginning. Through him all things were made;without him nothing was made that has been made. In him was life, and that lifewas the light of men. The light shines in the darkness, but the darkness has not

understood it. There came a man who was sent from God; his name was John. Hecame as a witness to testify concerning that light, so that through him all menmight believe. He himself was not the light; he came only as a witness to the

Semiotica 1361/4 (2001), 6984 00371998/01/01360069# Walter de Gruyter

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light. The true light that gives light to every man was coming into the world.(The Gospel according to John 1: 19)

These texts are the basis upon which the Middle Ages built its ideas on themetaphysics of light.Plato basically uses the metaphor about light which had become

commonplace in Greek philosophy and literature in an epistemologicalsense (Bultmann 1948: 136). The epistemological use which Plato madeof it must have had a great influence: the knowledge of external thingsis explained on the basis of an anity with the bodily vision determinedby the presence of the sun, just as the fact that objects of knowledge owetheir real existence to good is resolved with the conformity that there isbetween the existence of real objects and the sun. In this way not only theknowledge of things but also their being is explained by means of analogywith the behavior of light.If Plato provides the first reference of Middle Ages thought on light,

then the other is the Bible. Many metaphors of light can be found, aswe have seen, in the Old Testament but the most famous passage of all,the one which has influenced medieval ages thought is no doubt the onein the Gospel according to John.The Middle Ages was full of similar images of light through authors

like Phylo of Alexandria and Plotinus. In Enneades V, 1,6 Plotinus tries toexplain how the one who is self-included and self-sucient in his beingcan give rise to other beings:

Splendour spread all around which emanates like this from Him, but from He

who has stopped, like in the sun, the splendour which almost makes a halo aroundHim; the splendour which regenerates, eternally from Him who is stopped. Afterall, as long as they last, all Beings emanate a certain necessary existence all around

them and outside them from the bottom of their essence. This is connected to thepresence of their operating virtue and is like a figure of the archetypes from whichit germinated: fire emanates eternal heat; and snow does not only retain cold

within itself; but a magnificent test of what has been said is given by all fragrantsubstances. Something comes out of them for all of their lifetime stays aroundthem so that their neighbour gains pleasure from their very existences. Moreover,

all Beings who have reached maturity, generate; however, whatever is alwaysperfect, always generates and into eternity; and generates, of course, somethinglower than his own being. (Plotinus 19471949, vol. III, part I: 1112. Mytranslation)

Further on he adds:

Well, in order to be more reasonable, we would like to see the operating force,which flows, as it were, from Him, as if it flowed from a sun. Let us, therefore take

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it for granted that even the complete spiritual absence is, in a certain sense, a lightand that He, on the other hand, has stopped on the top of the world of thespirit and reigns over it without rejecting it widespread splendour by itself, but

by eternally radiating even though he is immobile on the world of the Spirit.(19471949, vol. III, part I: 4344. My translation)

Plotinus thus explains the origin of the visible world by means of themetaphor of light and during the course of the argumentation he makesirradiation the material which constitutes the real world when he statesthat all existing things produce images of themselves directed at whatsurrounds them. This argumentation, where Plotinus states that all thingsirradiate images of themselves, could be used for metaphysical aims, andwould later have significant repercussions on the physical interpretationof the world and would be an important precedent in the doctrine of themultiplication of the species of the thirteenth century.Plotinus also provides some other ideas which were to be used later by

other medieval authors. In the first Ennead for instance, Plotinus pointsout that light or fire is the form of matter: The beauty of color issomething simple, concerning a shape and is due to the victorious pres-ence of light incorporated reality, reason, idea over the obscurityof matter. This is why fire is beautiful in itself more than any other body.If it is compared to other elements, it could almost be likened to Idea: itis in fact the highest in terms of position; the thinnest of all; almost at thelimit of incorporeal nature. It not only encloses other things in itself,whereas the others enclose it; these things get hot when in contact withit, whereas it never gets cold. Moreover, fire has color inborn, the otherthings receive the form of color from it: It shines and radiates as ifit were an Idea. But whatever looses its light because of a lack of vigour,is no longer beautiful, because it does not participate completely inthe idea of color (19471949: I, 101). This statement of light as thefirst bodily form by Plotinus reappeared in the same form in Grossetesteas well as in St. Bonaventure.Even St. Augustine in his synthesis of Christianity and neoplatonism in

which light is the main element, uses the light metaphor1 to describenot only the reality of the created Universe environment but also of itsCreator and of his relationship with the creatures. In De Trinitate, forinstance, St. Augustine states that the three persons of the Trinity makeup a single light and explains the relationship between them by meansof a consideration on light.2

The theory of illumination, which is one of the trademarks of theAugustine tradition, is based on the light metaphor: God is the archetypallight and all the other lights are nothing but derivations of it. Gods

Two thirteenth-century theories of light 71



uncreated light is light in the true sense of the word, whereas all otherlight is partaken light. St. Augustine adds an important epistemologicelement to this nucleus that forms the heart of the illumination theory: theidentification between light and truth: all that is manifest is light andthe form of good shines upon all intelligible things so that they canbe known.3 In order to understand intelligible things, the mind must beilluminated by divine light, just as the human eye has to be illuminatedby bodily light in order to see sensitive things.The rich medieval tradition of using the motif of light for theological,

metaphysical, and epistemological purposes derives not only from theancient and patristic sources, but also from the neoplatonism Arabinterpretations.The position of Al-Kindi is an excellent example of this. In De radiis

(Al-Kindi 1974; cf. also Federici Vescovini 1965: 4447; Thorndike 1923:642646), which had a great influence in the thirteenth century, above allinside the Franciscan school in Oxford, Al-Kindi supports the theoryof the fundamental dependence of the bodily world on the arrangement ofthe stars because they send their rays to the world. The irradiationdepends on the nature of star, on its position, the radiation mode (rayscoming from the centre of a star are stronger than those comingfrom other parts of the star), and on the combination of rays coming fromdierent stars, so that each dierent place has rays of diering strengthcoming from the total harmony of the stars (1974: 220. My translation).Then, according to Al-Kindi, everything and not only stars emit light,

which goes in all directions so that everywhere in the world containsrays which come from everything which has actual existence (1974: 224).As a consequence of this everything in the sublunary world acts on all theother things: the rays of fire transmit heat, the rays of the earth transmitcold, medicine spreads its rays throughout the body, colliding bodies emitrays which transmit sound, magnets attract iron by means of theirradiation; even images of the mind produce rays and feelings, desire,hope, and fear influence the rays emitted by everybody and thus the thingswhich those rays strike.The most important contribution ofDe radiis was that of having taught

medieval scholars, amongst whom were Grosseteste and Bacon, thatevery creature in the universe is a source of radiation and that the universeitself is made up of a great network of forces: this was to become thecentral doctrine of the multiplication of the species theory formulated inthe thirteenth century.Thirteenth century philosophers were also influenced by another

treatise of Al-Kindi, De aspectibus, in which Al-Kindi analyzed radiationfrom a mathematical and physical point-of-view. They considered this

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point of view to be applicable to the theory of rays contained in De radiis.The thirteenth century authors, who knew both treatises and probablyconsidered them to be two aspects of the same problem, no doubt dis-covered the possibility of a mathematical and physical analysis of thetheory of universal radiation of forces in Al-Kindis work.Another text had a great influence on the theory of the multiplication of

the species: Fons Vitae by Avicebron.4 The central point of Avicebronstheory is the universal hylomorphism doctrine according to which allsubstances excluding God consist of matter and form. The theory of theplurality of forms is equally important. According to this theory a greatnumber of forms are added to the universal matter created by God alongwith the universal form in order to reach the actuality in the various beingsin the universe. This great number of forms determines the particular stateand the particular place of everything in the scale of beings.These ideas would have had a particular influence on the Franciscans of

the thirteenth century and above all on St. Bonaventure. What interests usmost, however, is Avicebrons teachings on emanation. The influencewhich any intermediate substance has on the others occurs

thanks to the sublime universal cause because power which is the author of allthings and moves all things by itself works until it finds something which receivesits action _ And because the first author is the one who distributes the formwhich is within him, he cannot stop it flowing from him; he is thus thesource which maintains, develops and includes everything that is. All thesubstances must, therefore, obey his action and imitate him in giving theirforms and in granting their energy, for all the time that they find a matter ready

to receive it. _ In brief, the first emanation, which includes all the substances,makes emanation of substances from one to another necessary. Take the sun asan example of this, it does not emanate for itself and does not communicate its

rays except for the fact that it falls under the first emanation and obeys it.(Avicebron 1859: 106108. My translation)

All substances, thus, emanate their form as an imitation of the firstauthor: this emanation, however, does not imply a flow of essence or ofsubstance but simply of its force (vis) or of its rays (radius). Avicebronclaims that these forces or rays are spiritual even when they come fromthe body and insists that everything which emanates from somethingis the image of the thing from which it emanates (Avicebron 1859: 136).The action which Avicebron has in mind is a metaphysical action ratherthan a physical one and this is the thing which distinguishes the doctrineof Avicebron and that of Al-Kindi of the universal radiation of force.Robert Grossetestes thought comes from the mingling of neoplatonism

and Arab tradition. He develops a vast philosophy of light of neoplatonic




inspiration, which consists of: (1) an epistemology of light, in which hesustains that intelligible things can only be gathered if they are illuminatedby a spiritual light; (2) a metaphysics or cosmogony of light; (3) a physicsof light; (4) a theology of light which is used as a metaphor on light toexpress theological truth. Here we will be treating the second and the thirdof these points above all.In Grossetestes De luce he states:

And it is clear also because every superior body is the species and the perfection of

the subsequent body, according to the light generated by itself; and just as thenumber one can, in a certain way, be every subsequent number, in the same waythe first body is each of the derived bodies because of the multiplication of its light.

(in Rossi 1986: 120. My translation)

and describes the generation of bodily things by means of the action ofa point of light created from nothing (ex nihilo). Grosseteste thus showshis complete refusal of the idea of emanation which use of the metaphorof light implied within a neoplatonic perspective.The main point of Grossetestes doctrine is that light is the prime bodily

form. At the beginning of time, God had created a point of light as thefirst form of the prime matter. However, both the point of light andthe prime matter have no extension. The extension comes about when thepoint of light, whose characteristic is its capacity to spread out in alldirections at the same time, takes the matter with it during its expansioncreating a sphere.

I consider that the prime bodily form which some call corporeity, to be light. The

very nature of light means that it spreads out in all directions. This means thata large limitless sphere is generated instantaneously from a luminous point, unlessan opaque body comes between it. Corporeity is what is necessarily produced by

the extension of the matter in the three dimensions, even though both the cor-poreity and the matter is essentially simple substance, without any dimension.Actually it was not possible for the form, which was simple and without dimen-

sion, to give dimension to every part of the matter, which was in turn simple andwithout dimension, unless it multiplied itself and immediately extended itself inevery direction. In this way it would drag matter while extending because form assuch cannot be separated from matter, since it is not divisible from it, nor can

matter be deprived of form. (in Rossi 1986: 113114. My translation)

According to Grosseteste, therefore, infinitesimal quantities infinitelymultiplied produced a finite quantity. During the multiplication process,the corporeal substance produced becomes increasingly rarefied until itreaches the completion of its potential at the maximum of rarefaction.The outermost sphere generated in this way, which has no consistency but

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is fully actualized prime matter and prime form, is the firmament which isthe external limit of the bodily universe. The firmament, in turn, diusesits light inside towards the center of the universe, producing additionalrarefaction in the highest areas and leaving the lowest regions more con-densed (cf. Rossi 1986: 1213). The nine celestial spheres and four elementspheres are produced by this rarefaction and subsequent condensationprocess.If this is the outline which defines Grossetestes cosmology of light, in

other words if his theory on the origin of the universe is well structuredand developed, we can say that his physics of light is less rich. Actuallywe can see some mentions of his physics of light in a few paragraphs ofDe lineis, angulis et figuris:

the natural agent extends his force from himself to the patient both when it acts

on the sense and on the matter. This force is sometimes called species andsometimes resemblance, and is the same thing whatever it is called; it transmits thesame influx to the sense and to the matter or to its opposite, just as heat transmits

the same influx to touch and to a cold body _ but dierent eects are obtainedbecause of the dierence of that which is subjected to the action. As far as thesenses are concerned, this force does actually have a certain spiritual and more

noble action, once it has been received; as far as its opposite or matter is con-cerned, it has a material action, like the sun with the same influence on dierentobjects produces dierent eects: it can actually dry mud and melt ice.(Grosseteste in Rossi 1986: 129130. My translation)

This is what Robert Grosseteste says about the physics of light, but itsexplanation is to be found in a few sentences of another work; De naturalocorum. There, after having stated the geometrical rules which govern thepropagation of the rays, Grosseteste writes:

These rules, bases and foundations have been obtained by the power of geometry,

a diligent investigator of natural things can in this way specify the causes of allthe natural eects. He cannot do this in any other way, as has already beendemonstrated in general terms, because every natural action is varied in terms

of force and weakness according to the variations of line, angles and figures.(Grosseteste 1912: 6566. My translation)

If all the natural eects can be explained geometrically in terms oflines, angles, and figures, this is because all natural eects are causedby radiation of force.Grosseteste follows Al-Kindi in the analysis of geometric optics with his

rules on the straight line propagation and on the reflection and refractionof light, and he also extends the physics of light so that the theme of




light becomes the thing which distinguishes his presence in the history ofideas (cf. the classics studies of Baur 1912 and of Crombie 1953).On the other hand, it is also true to say that his theory of light should be

interpreted in the exegetic tradition of the book of Genesis, because thefundamental assumption of his whole theory is verse 1: 3 of the book ofGenesis: dixitque Deus: fiat lux. Also just as in the book of Genesis,light illuminates and gives form to matter, in De luce light is consideredthe first forma corporeitatis of a prime matter without form. As P. Rossistates: This is why light is considered a corporeity because it is in itsnature to spread, to extend in every direction, giving dimensions to theprime matter, which is dragged by the light in its necessary spreading. It isnot correct to say that light gives origin to corporeity but light itselfis corporeity, three-dimensionality (1986: 1011). This is why Grossetesteis able to conclude:

Light, therefore, which is the first form in the prime matter created, was spread atthe beginning of time and pulled as large a quantity of matter as the structure

of the universe by multiplying itself for everywhere in an endless process andby extending itself in every direction in the same measure. (in Rossi 1986: 114.My translation)

The treatment of the cosmogonic process follows this statement,according to the structure which we have already mentioned and whichgives rise to a defined and perfect universe, which is also to a certainrespect harmonious. The opuscule ends on the theme of harmony and onthe proportion of the universe. According to J. Mc Evoy (1982: 162167)the novelty and originality of it comes from the fact that Grossetestemakes a synthesis of the cosmology contained in the book of Genesisand the Aristotelian cosmology of De coelo. In other words Grossetesteuses the conception of the mathematical structure of the reality, expressedin a verse of the book of Knowledge (11: 21) omnia numero, pondereet mensura disposuisti to overcome the Aristotelian conception of thedeep distinction between the matter which makes up the celestial bodiesand that which makes up the sublunary world: in this sense light, the firstcorporeal form is the unifying element of the whole universe, because it isthe foundation of a system in which the first sphere has the principles ofall the others in itself, because they derive from the spreading and themultiplication of its light (Rossi 1986: 15. My translation).A direct consequence of the conception of light as original corporeity

is the statement that natural phenomena can be interpreted by means ofthe laws of optics: this is the theme running through De lineis, anguliset figuris in which Grosseteste (in Rossi 1986: 125131) tries to reducethe representation of phenomena, if not their explanation, to geometrical

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laws. This may have meant confirmation of the validity of Grossetestescosmological approach for himself.If the theme of light is used by Grosseteste in the mathematical-

cosmological sense, then in St. Bonaventure it takes on connotationswhich are more typically aesthetic-metaphysical. St. Bonaventure is,actually, the XIIIth Century thinker who gave the most importance tobeauty as an intrinsic and fundamental aspect of the physical universeand who focused the most attention on the aesthetic value (Corvino 1980:247) of light.In one of his early works Bonaventure considered the pulchrum as

one of the transcendental properties of the being, that is one of thoseproperties which all the beings have in common, like the unum, theverum, and the bonum.5 Compared to the traditional doctrine, this was anabsolute novelty which, however, Bonaventure did not dare to takeup again and develop in the future. In the Breviloquium (in Bonaventura18821902, V, 1891: 219) only three transcendental properties of the beingare actually indicated; St. Bonaventure, however, indicates another sixproperties6 of the things created which derive from the impression oforder and harmony which God wanted to give the world and which,therefore, are resolved in a certain way in aesthetic values.The fact is, however, significant because it indicates a characteristic

dimension of his speculative behavior. The first impression which thesensitive world produces in whoever perceives it, is an impression ofbeauty, of sweetness, of healthiness. In St. Bonaventures opinion allknowledge came from sensation,7 but every sensation is not a simple actof apprehension of the external object because it is accompanied by afeeling of pleasure (oblectatio) which is something instinctive and prior toany reasoning. In other words it is a moment of pure subjective pleasure.If we then analyze this feeling, we will see that it has a triple specificationaccording to the senses used because it is either determined by the beautyof the perceived object, as it is with sight, or by the sweetness, as it is withsmell and hearing, or by its capacity to satisfy a vital need, like in tasteand touch.8 The moment of purely instinctive pleasure gives way tothe moment of intellectual reflection (diiudicatio) whereby we becomeconscious of the feeling we have experienced and we try to understandthe cause of it.9 Understanding the cause means discovering what isobjectively valid in the thing which is able to raise appreciation in us.Beauty, that is the sensitive value of things, in particular does not onlyexist in relation to a feeling or to an emotive state of the subject who isfeeling but has an objective basis in things because it corresponds toqualities which belong to their nature: these qualities are proportion andluminosity.10




This theme was not exclusive to St. Bonaventure but was researched bya large number of his contemporaries, however, for obvious reasons it wasabove all developed by the Franciscan school (Robert Grosseteste is justone example). Proportion makes up the quantitative and numerical aspectof the beauty of the world (symmetry, ordered size ratios), whereasluminosity is the qualitative aspect (brightness of light, variety of colors).The two aspects are complementary but go back to a common origin:

the idea of an ordered world in accordance with mathematical relation-ships which, as we have already said, originate from the biblical Book ofWisdom (11: 21): omnia numero, pondere et mensura disposuisti. Thisconcept which comes from such an authoritative source was added toand developed according to the teachings of the Pythagorean tradition,known to medieval people mainly through the writings on music ofSt. Augustine and Boethius.InDe institutione musica, I, 10 Boethius (1966 [1867]: 196197) recounts

the episode of Pythagoras who had discovered the relationship betweenmathematics and music while passing a blacksmiths yard and hearingthat the dierent sounds were produced by the dierent weight of thehammers which struck the anvil, in accordance with constant propor-tions. On the other hand the Latin term numerus also means rhythm:this is why the concept of harmony was commonly linked to that ofmathematical relationships. Thus, Bonaventure talks about harmony andproportion referred to characteristics of the beauty of Creation, he doesnot only intend them as the similarity of parts which are dissimilar to oneanother like symmetry, but also as disparity, possibility of grading,alternation of dierent things.11 The concept of proportion is also thebasis of the principle of analogy on which St. Bonaventures metaphysicsis founded.12

The other aspect of the sensitive world, luminosity, had already beenbrought up by Grosseteste in the Franciscan school with his theory onlight which tried to bring both the quantitative and numerical aspects aswell as the qualitative ones back to a single principle: light, in fact, con-ceived as the active principle of corporeity, spreads by its very nature in alldirections, in such a way that bodies extended into space generate fromthe dimensionless luminous point and these bodies can be studiedfrom a geometrical point of view.Light is, therefore, the principle of the mathematical structure of the

universe; it was the first thing created by God and because of its capacityfor spreading and multiplying it produced all other existing things.At the same time, because light in itself is the principle of beauty

(lux per se pulchra est), it takes the intrinsic beauty of Creation intoaccount. This theory is taken up again by St. Bonaventure who inserts it

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organically into his doctrinal system. Just as light spreads and multipliesitself13 for Robert Grosseteste it also does so for St. Bonaventure becauseof its own intrinsic energy; and just as for Robert Grosseteste light is thefirst form created in the prime matter, it is so for St. Bonaventure too.On the basis of an Aristotelian text quoted many times before (Aristotle,

Physics, II, 2, 194b, in Aristotle 1973: III, 32), St. Bonaventure (inSecundum Sententiarum, d. 12 a. 1 q. 1 concl., in Bonaventure 18821902:294) considers that matter is always in relation to a form and thusmatter which is totally lacking in any form is only imaginable by meansof an act of abstraction from our mind, but does not exist in nature.All beings, except God who is pure form and pure act, consist of matterand form: in spiritual substances there is spiritual matter and in corporealsubstances there is corporeal matter but matter considered alone is neitherspiritual nor corporeal14 because it is something intangible. There is noMatter in any place or in any time which can be potential alone, in otherwords a potential being which is really halfway between the non-beingand the being in act.15

Even at the beginning of time, when the prime matter was directlycreated by God, it was created with a cover of some form: the idea ofprimordial chaos is a poetical image not a scientific and philosophicconcept.16 In other words corporeal matter was never a formless and inertmass, because the first form which was given to it from the beginning oftime was light as active principle. This idea seems to have been given morecredit with experience, because there are no bodies on earth which are soopaque that they cannot become shiny or sparkling by means of someprocess of refinement or purification like in the case of sand whichbecomes glass or of mineral which becomes a gem.17 The greater or lesserparticipation in the active principle of light is what makes up the degreeof reality and of perfection of the bodies.The fundamental characteristic of light is that of being the most active

of all corporeal forms, so much so that it was considered almost anintermediary between the corporeal forms and spiritual ones. It is the firstform which actuates the bodies, which gives them extension (because ofits spreading, its capacity for multiplying, dragging the passive and inertmatter with itself ), preparing them to receive any other form. It also givesall the other forms stability and operative capability.18

Light cannot, therefore, be simply an accidental form but a substantialform; however, the color and the brilliance which are accidental formsand sensitive qualities derive from the light which strikes a body as itssubstantial form.19

The Bonaventurian doctrine of light implies some importantconsequences regarding the simple elements which make up the bodies.




According to St. Augustine there are four elements: water, air, fire, andearth; St. Augustine, like nearly all Christian thinkers, does not thinkthat celestial bodies are made of a dierent matter to that which makes upthe bodies of the sublunary world. Aristotle on the other hand consideredfive elements, in other words, apart from the four elements alreadymentioned, he suggested a fifth (ether) characteristic of the heavenswhich is distinguished from the others because of its inalterability andincorruptibility.St. Bonaventure sides with Aristotles theory, but adds an important

modification, because he identifies the fifth element as light (cf. thequestion entitled: An Firmamentum sit idem cum ignis elemento,In secundum Sententiarum, d. 14 p. 1 a. 1 q. 2, in Bonaventure 18821902:338341). In some critics opinions this choice may be motivated by a lovefor symmetry, by a need to obtain a perfect correspondence betweenmicrocosm and macrocosm: because mans external senses are five, therehave to be five elements (Mc Evoy 1973: 333334). Actually St. Augustine(De genesi ad litteram, 1887: III, 4, 6) as well as Aristotle (De anima,l, 424b, in Aristotle 1973: III, 161) had tried to make the number of sensesof man correspond to the elements of the bodies, but because he suggestedfour elements and five senses, there was no balance; St. Bonaventure(Itinerarium mentis in Deum, c. 2, 3, in Bonaventure 18821902, V, 1891:300), on the other hand, by adding light as the object of sight, managedto make things balance.Having seen that the real reason is this, it does not mean that the

Bonaventurian theory is without some interesting conclusions from aphilosophical and scientific point-of-view. It should be first noted thatAristotle considered a fifth element for religious needs, because he con-sidered the heavens the seat of the Gods (De coelo, I, 3, 270b, in Aristotle1973: 247) and, therefore, consisting of an eternal and almost divine sub-stance whose nature was very dierent from that of the bodies in thesublunary world. By identifying the fifth element as light, St. Bonaventuremanaged to make the theory of Aristotle void of any religious-Pagansignificance and could follow his astronomic doctrines without havingto accept the implications which did not concern scientific knowledge.The unusual similarity introduced by the power of light in the corporeal

complexion of man thus becomes a key concept. It must not, however, beconsidered in quantitative terms as if all the elements had been weighedand mixed without considering their diering properties, but rather in aqualitative sense which consists of a proportioned equilibrium of theelements joined together according to appropriate proportions and tothe needs of the form to which the body is destined. The celestial naturecan, thus, be predicated to anything if taken in the qualitative sense. It is

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in this sense that it is said that the spirit, which belongs to the complexionof every animal body and in a privileged manner to the human body, is ofcelestial nature: it comes from a mixture of the elements in a certainharmony and in a certain agreement.Now the harmony which is to be found in the human body is of a degree

higher than that to be found in any other body and from this it is derivedthat its vital warmth, its spirit and its energy reach a single degree ofconformity to the five elements. The fact that light comes into the con-stitution of the human body in a privileged manner is proved by thequality of its complexion and its dignity.St. Bonaventure thus hopes to have demonstrated that the dignity of

the human body is something unique which consists of incomparableharmony and of proportioned conjunction of its parts. At this state of ourpilgrimage this harmony makes the human body similar to the nature ofthe heavens and prefigures its glorification after the resurrection andits exaltation beyond the Heavens, in the light of the Empyrean(cf. Bonaventure, In secundum Sententiarum, d. 17 a. 2 q. 2 ad 6,in Bonaventure 18821902: 423).

Notes

1. Thonnard 1962 identifies ten dierent senses in which St. Augustine uses the term light.

2. Verbun enim Patris est Filius, quod et Sapientia eius dicitur. Quid ergo mirum si

mittitur, non quia inaequalis est Patri, sed quia est emanatio quaedam claritatis

omnipotentis Dei sinceris? Ibi autem quod manat et de quo manat unius eiusdem

substantiae est. Neque enim sicut aqua de foramine terrae aut lapidis manat, sed sicut lux

de luce. Nam quod dictum est: Candor est enim lucis aeternae, quid aliud dictum est

quam lux est lucis aeternae? Candor quippe lucis quid, nisi lux est? Et ideo coaeterna luci

de qua lux est (De Trinitate, 4.20, in St. Augustine 1973: 220).

3. sed potius credendum mentis intellecualis ita conditam esse naturam, ut rebus

intelligibilibus naturali ordine disponente Conditore subiuncta sic ista videat in quadam

luce sui generis incorporea, quemadmodum oculus carnis videt quae in hac corporea luce

circumadiacent, cuius lucis capax eique congruens est creatus (St. Augustine 1973: 496).

4. Cf. Avicebron, Fons Vitae, 1859, also for translations into Medieval Latin, English, and

French.

5. Cum assignantur quator conditiones entis communiter, scilicet unum, verum, bonum

et pulchrum, quaeritur qualiter distinguuntur et penes quid sumantur _ (in Henquinet1932: 654).

6. Omnis enim creatura constituitur in esse ab eciente, conformatur ad exemplar

et ordinatur ad finem; ac per hoc est una, vera, bona; modificata, speciosa, ordinata,

mensurata, discreta et ponderata (in Henquinet 1932: 654).

7. Homo igitur, qui dicitur minor mundus, habet quinque sensus quasi quinque portas, per

quas intrat cognitio omnium, quae sunt in mundo sensibili, in animam ipsius

(Bonaventure, Itinerarium mentis in Deum, c. 2, 3, in Bonaventura l8821902,

V, 1891: 300).




8. Ad hanc apprehensionem, si sit rei convenientis, sequitur oblectatio. Delectatur

autem sensus in obiecto per similitudinem abstractam percepto vel ratione speciositatis,

sicut in visu, vel ratione suavitatis, sicut in odoratu et auditu, vel ratione salubritatis,

sicut in gustu et tactu, appropriate loquendo. Omnis autem delectatio est ratione

proportionalitatis (Bonaventure, Itinerarium mentis in Deum, c. 3, 5, in Bonaventura

18821902, V, 1891: 300).

9. Post hanc apprehensionem et oblectationem fit diiudicatio, qua non solum diiudicatur,

utrum hoc sit album vel nigrum, quia hoc pertinet ad sensum particularem; non solum

utrum sit salubre vel nocivum, quia hoc pertinet ad sensum interiorem; verum etiam,

qua diiudicatur et ratio redditur, quare hoc delectat; et in hoc actu inquiritur de ratione

delectationis, quae in sensu percipitur ab obiecto. Hoc est autem, cum quaeritur ratio

pulchri, suavis et salubris: et invenitur, quod haec est proportio aequalitatis

(Bonaventure, Itinerarium mentis in Deum, c. 2, 6, in Bonaventura 18821902, V,

1891: 301).

10. Pulchritudo autem rerum secundum varietatem luminum, figurarum et colorum

in corporibus simplicibus, mixtis et etiam complexionatis, sicut in corporibus

caelestibus et mineralibus, sicut lapidibus et metallis, plantis et animalibus

(Bonaventure, Itinerarium mentis in Deum, c. 1, 14, in Bonaventura 18821902, V,

1891: 229).

11. necesse est quod ex quadam convenienti diversitate, in quadam proportionali

gradatione consurgat quaedam convenientia ordinata et pulchritudo in genere creaturae

perfecta (Bonaventure, In secundum Sententiarum, 6d. 9 a. un. Q. 8, in Bonaventura

18821902, II, 1885: 255256).

12. In order to resolve the antinomy between the univocalness or the equivocalness (the use

of identical words to indicate things which have nothing in common) of the attributes

which we give to God and to finished Beings St. Bonaventure uses mathematical

concepts of proportion (intended as a ratio between quantities of a dierent size) and

proportionality (intended as the similarity between two ratios). He then tries to define

the concept of analogy on the basis of these models, in other words a way of attributing

which comes halfway between univocalness and equivocalness, which he considered

to be the only valid way to understand the mysterious reality which transcends our

experience.

13. quanto lumen est maius, tanto magis se diundit et multiplicat (Bonaventure,

In secundum Sententiarum, 2, d. 2, a. 1 q. 2 fund. 4, in Bonaventura 18821902, II,

1885: 73); cum lucis sit ex se ipsa se ipsam multiplicare (Bonaventure, In secundum

Sententiarum, d. 13 a. 2 q. 1 conclus., in Bonaventura 18821902, II, 1885: 318).

14. nam materia in se considerata nec est spiritualis nec est corporalis (Bonaventure,

In secundum Sententiarum, d. 3 p. 1 a. 1 q. 2 ad 3, in Bonaventura 18821902, II,

1885: 98).

15. Quamvis ens in potentia simpliciter inter non-ens et ens-actu sit medium _(Bonaventure, In secundum Sententiarum, in Bonaventura 18821902, d. 12 a. 1 q.

1 ad 6, II, 1885: 294).

16. Quidam namque voluerunt dicere quod materia illa diceretur chaos propter formarum

multitudinem et contrarietatem, quae erat in partibus materiae _ Sed iste modusponendi potius est poeticus quam philosophicus, quia magis sequitur imaginationis

fictionem quam rationem (Bonaventure, In secundum Sententiarum, q. 3 concl.,

in Bonaventura 18821902, II, 1885: 300).

17. Et quod omnia corpora naturam lucis participent, hoc satis de plano ostendunt, quia

vix est corpus opacum, quin per multam tersionem et politionem possit eci lumino-

sum, sicut patet, cum de cinere fit vetrum, et de terra carbunculus (Bonaventure,

82 L. Miccoli



In secundum Sententiarum, d. 13 a. 2 q. 2 concl., in Bonaventura 18821902, II,

1885: 321).

18. Forma enim lucis cum ponitur in eodem corpore cum alia forma, non ponitur sicut

dispositio imperfecta, quae nata sit perfici per ultimam formam, sed ponitur tamquam

forma et natura omnis alterius corporalis formae conservativa et dans ei agendi

ecaciam; et secundum quam attenditur cuiuslibet formae corporalis mensura in

dignitate et excellentia (Bonaventure, In secundum Sententiarum, d. 13 a. 2 q. 2 ad 5,

in Bonaventura 18821902, II, 1885: 321).

19. Verum est enim quod lux, cum sit forma nobilissima inter corporalia, sicut dicunt

philosophi et Sancti, secundum cuius partecipationem maiorem et minorem sunt cor-

pora magis et minus entia, est substantialis forma. Verum est etiam quod, cum lux sit per

se sensibilis, sit etiam instrumentum operandi, sit etiam augmentabilis et minuibilis,

salva forma substantiali, quod ipsa habet naturam formae accidentalis (Bonaventure,

In secundum Sententiarum, d. 13 a. 2 q. 2, in Bonaventura 18821902, II, 1885: 321).

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latino translata ab Johanne Hispano et Dominico Gundissalino, C. Baeumker (ed.). In

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Columbia University Press.

Lucia Miccoli (b. 1949) is Professor of Medieval Philosophy at Bari University, Italy. Her

principal research interests include epistemology and the relationship between science and

technology in the twelfth and thirteenth centuries. Her major publications include

Quaestiones disputatae a magistro Gentili de Cingulo super Prisciano minori (1983),

Loggetto della conoscenza scientifica nel Prologo del Commento alle Sentenze di G. da

Rimini (1987), and Il problema dei futuri contingenti in Anselmo dAosta (1987).

84 L. Miccoli



[doi 10.1515%2fsemi.2001.099] l. miccoli -- two thirteenth-century theories of light- robert...

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