site: bonaventure

collection: Book II: On the Creation of Things

title: Dist. 13, Art. 3, Q. 1

author: St. Bonaventure

languages: en la

title: Opera Omnia (Quaracchi critical edition)

publisher: Collegii S. Bonaventurae

source_text:
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## ARTICULUS III.

### *De lucis effectu et irradiatione.*

Consequenter quaeritur de lucis effectu et irradiatione. Et circa hoc quaeruntur duo. Primo quaeritur, utrum *lumen*, quod emittitur a corpore luminoso, sit corpus, an qualitas corporalis. Secundo, dato quod sit qualitas, est quaestio, utrum sit substantialis, vel accidentalis.

### Quaestio I. *Utrum lumen, quod exit a corpore luminoso, sit corpus.*

Circa primum sic proceditur et ostenditur primo, quod lumen, quod exit a corpore luminoso, sit corpus.

*Ad oppositum.*

1. Omne quod per se movetur localiter et dimensive, est corpus[^1]; sed radius sive lumen egrediens a sole, movetur localiter, utpote ab oriente in occidentem: ergo tam radius quam lumen est corpus.

2. Item, nihil repercutitur et repellitur a corpore nisi corpus; «*impossibile enim est, non-corpus a corpore moveri*[^2]»; sed luminis et radiorum fit repercussio ad corpus opacum: ergo tam lumen quam radius est corpus.

3. Item, impossibile est, esse confractionem et intersecationem nisi corporum; sed ex repercussione luminis ad speculum concavum fit radiorum intersecatio et confractio: ergo videtur, quod tam lumen quam radius sit corpus.

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4. Item, omne quod habet trinam dimensionem, est corpus[^3]; sed lumen in medio habet trinam dimensionem, quia diffunditur secundum omnem positionem, nec tantum est in superficie, immo etiam penetrat aërem usque ad profundum: ergo videtur, quod lumen in medio sit corpus.

5. Item, esto quod sol esset, et circa ipsum esset spatium vacuum, cum sol potens sit ex virtute lucis absque adiutorio extrinseco lumen suum diffundere, nisi habeat resistens, et in illo spatio vacuo nullam habeat resistentiam, ibidem lumen suum diffunderet; sed lumen illud non esset in alio corpore sustinente: ergo videtur, quod esset substantia per se ens[^4]; et non spiritualis, hoc constat: ergo corporalis.

6. Item, quod potest generare corpus est corpus[^5]; sed lumen in medio diffusum potest generare corpus, scilicet ignem, per sui multiplicationem: ergo lumen in medio est corpus.

*Ad oppositum:*

*Fundamenta.*

1. Philosophus secundo de Anima[^6]: «*Lumen nec est corpus nec defluxus corporis*».

2. Item, hoc ratione videtur per suum oppositum. Lumini enim opponitur tenebra privative[^7]: si ergo privatio non est corporis, sed formae, lumen non est corpus, sed forma.

3. Item, hoc videtur per *motum*. Nullum enim corpus movetur subito secundum locum; sed lux subito alterat, quia in instanti ab oriente venit in occidens: ergo lumen non est corpus. Si tu dicas, quod non movetur subito, sed repente; hoc non potest stare secundum Philosophum[^8], quia si repente moveretur, id est imperceptibiliter in aliquo spatio, in maiori spatio posset sentiri successio, sicut patet in sono: ergo etc.

4. Item, nullum corpus velocius movetur quam corpus mobilis primi, pro eo quod ille motus est perfectissimus omnium motuum, et ideo velocissimus[^9]; sed lumen ab oriente in occidens multo citius movetur, quam moveatur orbis primus, quia lux in instanti, et illud saltem in duodecim horis: ergo lumen non est corpus.

5. Item, nullum corpus simul et semel movetur ad partes oppositas[^10]; sed lumen simul et semel movetur ad partes oppositas, quia diffunditur sursum et deorsum, ante et retro, a dextris et a sinistris: ergo non potest esse corpus.

6. Item, impossibile est, duo corpora impermixta et non sese augmentantia esse simul; sed lumen cum aëre est impermixtum et ipsum aërem non augmentat, et tamen est simul: ergo non est corpus. Quod autem impossibile sit, duo corpora esse simul, et Philosophus[^11] dicit, et ad hoc sunt rationes, quae possunt omitti ad praesens, quia inducuntur in quarto, ubi agitur de penetrabilitate corporis gloriosi.

7. Item, nullum corpus habet suum esse in fieri continue; sed lumen in aëre habet suum esse in fieri, quia continue egreditur a sole, sicut dicit Augustinus[^12]: ergo impossibile est corpus esse.

8. Item, si lumen est corpus, aut est ex aliquo, aut est ex nihilo. Si ex nihilo: ergo est a creatione, ergo lumen est a solo Deo, cum ipsius sit creare[^13]. Si ex aliquo; quaero ex quo? aut ex corpore, a quo causatur, aut ex corpore, in quod suscipitur. Constat, quod non ex corpore, in quod suscipitur, quia lumen non producitur ex aëre; tunc enim ibi posset manere, recedente sole. Si ex corpore, a quo causatur: ergo videtur, quod corpus luminosum in emissione luminis aliquid perdit de sua substantia et materia, et ita videtur, quod iam sol deberet esse consumtus.

### CONCLUSIO.

> *Lumen et radius, prout proprie accipitur, non est corpus.*

**Respondeo:** Ad praedictorum intelligentiam est notandum, quod circa hoc quatuor fuerunt opiniones.

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*Opinio 1.* Quidam enim voluerunt dicere, quod tam lumen quam radius in medio *corpus* est, et egressus ipsorum radiorum ab ipso sole est sicut egressus rivulorum a fonte. Sicut enim a fonte procedunt rivuli, qui sunt corpora et eiusdem naturae cum fonte, sic dicunt esse in radiis et sole. Et si tu obiicias eis, quod videtur, quod substantia solis et aliorum luminarium iam esset pene consumta: respondent, quod sicut non consumitur substantia fontis, pro eo quod, sicut fit emissio, ita fit etiam restauratio; sic dicunt, quod non consumitur substantia solis, pro eo quod, sicut exterius emittit lumen suum inferius, sic virtute radiorum vapores ad se trahit superius, ex quibus restauratur, sicut corpus alimento, adeo ut nec deficiat nec decrescat. Et hoc videtur sensisse Seneca[^14]. — *Improbatur.* Positio tamen ista est contra philosophiam, quae dicit, corpora caelestia omnino esse incorruptibilia[^15].

*Opinio 2.* Secunda vero positio est, quod lumen est *corpus*, et similiter radii, et processus ipsorum radiorum a sole est sicut ramorum a radice, maxime si ita esset, quod statim radix posset ex se producere arborem, adiuta divina virtute, sicut forte fuit in prima rerum conditione; et sicut radix non diminueretur, si ita produceret arborem, et tamen dicerentur semper rami ab illa radice exire, non quia de novo egrediantur, sed quia cum sua origine continuantur: sic dicunt et in solis radiis se habere. Cum enim Deus solem tanquam originem et principium luminis fecit, simul cum hoc ramificationem radiorum sibi dedit; et sol continue dicitur illos radios emittere, quia illi radii nunquam separantur a sua origine; sed sicut sol movetur, sic radii circumferuntur, non novi generantur; eosdem enim radios, quos emisit a principio super terram, emittit etiam et nunc. — *Improbatur.* Sed esto, quod sol obscuraretur, sicut in passione Christi creditur esse factum[^16]; tunc videtur, quod oporteret ex tunc radios renovari, et ita de novo creari, si corpora essent.

*Opinio 3.* Tertia positio est, quod tam lumen quam radius in medio *corpus* est; et productio eius quantum ad *formam* est a sole, quantum vero ad *materiam* est a Creatore. Dicunt enim, quod hoc spectat ad perfectionem universitatis, ut, sicut est aliqua creatura, quae quantum ad materiam et formam immediate est a Deo, ut Angelus, quaedam, quae quantum ad formam est a Deo immediate et quantum ad materiam est a natura, ut homo; sic etiam tertium genus est, quod quantum ad formam est a creatura et quantum ad materiam a Deo. — *Improbatur.* Sed illud non videtur probabile, cum Deus nunquam creet materiam praeter formam aliquam[^17].

Licet autem quaelibet harum trium positionum specialiter dicat aliquid improbabile circa originem luminis ex lumine, omnes tamen communiter improbantur per hoc, quod dicunt, lumen in medio esse corpus, tum propter ipsius diffusionem, quae subita est, tum etiam propter coexistentiam cum aëre, quae impermixta est, tum etiam propter ipsius productionem, quae nec est ex materia nec unquam separatur ab eius existentia, immo sicut continue est, ita continue generatur; ut dicit Augustinus[^18], quod lumen habet permanentiam per continuam solis influentiam.

*Opinio 4 et conclusio.* Et ideo est quarta positio concors rationi et philosophiae, quod lumen et radius, si nominet illud praecise, quod a luce habet ortum, nec est corpus nec corporis defluxus, sicut rationes ad hoc inductae ostendunt. Si autem dicatur *radius* aer illuminatus secundum *diametrum*, et *lumen* aer illuminatus secundum *profundum*; sic isto modo radius et lumen poterit dici corpus. — *Conclusio 2.* Prout tamen proprie accipitur lumen et radius in medio, corpus non est.

*Solutio oppositorum.*

1. Ad illud ergo quod primo obiicitur, quod movetur localiter; dicendum, quod sicut videmus in specie generata a colore, quod dupliciter movetur, et unus motus est per diffusionem procedendo a corpore obiecto usque ad speculum, alius autem motus, secundum quod videtur moveri in speculo ad motum corporis obiecti — et primus non est motus localis, sed *generationis*, secundo vero motu non movetur per se, sed per accidens — *Distinctio.* sic intelligendum est in proposito, quod motus luminis, qui est per egressum ipsius a corpore lucido, non est proprie loci mutatio, sed magis luminis *generatio* et *diffusio*; et hoc patet ex hoc, quod fit subito in spatio quantumcumque magno. — *Notandum.* Motus vero alius, qui est per delationem ipsorum radiorum super terram cum ipso sole, iste est solum per accidens, sicut movetur virtus ipsa ad motum sui principii influentis; et tamen virtus corpus non est. Sic intelligendum est de lumine, quod se habet ad corpus luminosum per modum virtutis influxae. Unde Damascenus[^19]: «*Dicimus propter lumen, quod ex ipso provenit, lucere ignem, et non ponimus, ministeriale organum ignis esse, quod ex ipso est lumen, virtutem vero magis naturalem*».

2. Ad illud quod obiicitur, quod radii repercutiuntur a corpore; dicendum, quod repercussio alicuius ab aliquo potest esse dupliciter: — *Duplex repercussio.* quaedam ex collisione duorum sibi invicem obviantium, sicut pila repercutitur a pariete; quaedam ex ineptitudine patientis ad suscipiendam virtutem agentis, et sic repercutitur radius a corpore opaco. Sol enim, sive quodcumque aliud corpus luminosum, habet virtu-

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tem diffundendi lumen usque ad aliquod spatium determinatum, cum sit virtutis finitae; et quamdiu se protendit illa virtus, multiplicatur lumen, si susceptibile sit idoneum: — *Ad perspectivam.* cum vero ante terminationem illius virtutis obviat aliquod corpus, quod non est idoneum ad eius susceptionem, hoc ipso quod lumen non poterat se multiplicare in anterius, multiplicat se retrorsum, non ex virtute corporis resistentis, sed ex virtute primi moventis. Unde cum fit repercussio radii in aqua, mota aqua, movetur radius, non quia aqua sit principium movens, sed prima virtus radium producens, quae, occasione accepta ab aqua, poterat[^20] radium reflectere, et occasione accepta ab eadem, potest reflexionem variare et ita radium movere. — Quod enim dicitur: *impossibile est, non-corpus a corpore repelli*[^21]; — *Distinctio.* dicendum, quod si est aliquid ita non-corpus, quod sit spiritus, hoc verum est. Si autem est ita non-corpus, quod quidem indiget corpore deferente, sic absque dubio repelli potest; sicut praedictum est in lumine, et manifestum est in imagine, quae relucet in speculo propter appositionem plumbi cum vitro, quod est corpus opacum. Si enim esset solummodo vitrum per se, quod est corpus pervium, transiret species et non rediret ad oculum, sicut patet per sensibile experimentum.

3. Ad illud quod obiicitur, quod fit intersecatio[^22] et confractio radiorum; dicendum, quod hoc dicitur ratione aëris coniuncti, qui ex virtute radiorum ibi concurrentium habet subtiliari et moveri; et ratione illius dicuntur etiam radii confringi, dum ex multiplicatione secundum oppositas vias, per progressum et regressum, fit quaedam multiplicatio et aggregatio luminis et subtiliatio aëris circa corpus tersum; ex qua contingit, effectum calorem radii intendi, et ignem ibidem per caloris intensionem ex aëre sic subtiliato generari.

4. Ad illud quod obiicitur, quod lumen habet trinam dimensionem in medio; — *Distinctio.* dicendum, quod dimensionem potest aliquid habere dupliciter: vel ex *se*, vel ex ratione *eius, in quo est*. Si *ex se*, sic est corpus; si aliunde, non oportet. Sic enim habet trinam dimensionem albedo in cerussa et nive, quae sunt albae intra et extra[^23].

5. Ad illud quod obiicitur, quodsi circa solem esset vacuum, quod illuminaret; — *De vacuo illuminando.* dicendum, quod licet aliqui hoc dixerint, tamen non videtur verum nec probabile. Philosophus enim contrarium sentit in secundo de Anima[^24], cum dicit, quod «*per vacuum non est videre*»; et Augustinus similiter in duodecimo Confessionum, in principio dicens sic: «*Ubi lux esset, si esset, nisi superesset eminendo et illustrando*»? — Ratio etiam est contra hoc, quia, cum lumen sit forma corporalis, indiget medio deferente. Et si tu quaeras, quid impediat; dico, quod hoc non est propter praesentiam impedimenti, sed propter absentiam adiutorii: sicut si aliquis habens magnam famem et carens cibo non potest comedere, non quia impediatur, sed quia non adiuvatur.

6. Ad illud quod obiicitur, quod lumen generat corpus; — *Notandum.* dicendum, quod lumen non agit propria virtute, sed virtute corporis luminosi; corpus autem luminosum non educit corpus quantum ad materiam, sed solummodo quantum ad formam: et ideo cum lumen sit illud, per quod agit, non oportet, lumen esse corpus, sed sufficit, quod sit forma corporalis.

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## ARTICLE III.

### *On the effect and irradiation of light.*

Next it is asked about the effect and irradiation of light. And concerning this two [things] are asked. First it is asked, whether the *lumen* which is emitted from a luminous body is a body, or a corporeal quality. Secondly, given that it is a quality, [there is the] question whether it is substantial or accidental.

### Question I. *Whether lumen, which goes forth from a luminous body, is a body.*

Concerning the first it is so proceeded and shown first, that the *lumen* which goes forth from a luminous body is a body.

*Against the opposite.*

1. Everything which is moved through itself locally and dimensionally is a body[^1]; but the ray or *lumen* going out from the sun is moved locally — that is, from east to west: therefore both the ray and the *lumen* is a body.

2. Likewise, nothing is reverberated and driven back from a body except a body — «*for it is impossible that a non-body be moved by a body*[^2]»; but reverberation of light and rays occurs at an opaque body: therefore both *lumen* and ray is a body.

3. Likewise, it is impossible that there be refraction and intersection except of bodies; but from the reverberation of light at a concave mirror occurs an intersection and refraction of rays: therefore it seems that both *lumen* and ray is a body.

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4. Likewise, everything which has the three dimensions is a body[^3]; but *lumen* in a medium has the three dimensions, because it is diffused according to every position, nor is it only on the surface — rather it even penetrates the air into the depth: therefore it seems that *lumen* in a medium is a body.

5. Likewise, suppose that the sun existed and around it there were a vacuum: since the sun is able by the power of light, without extrinsic help — unless it has [something] resisting — to diffuse its *lumen*; and in that vacuum it would have no resistance; in the same place it would diffuse its *lumen*; but that *lumen* would not be in another sustaining body: therefore it seems that it would be a substance existing through itself[^4]; and not spiritual — this is established: therefore corporeal.

6. Likewise, that which can generate a body is a body[^5]; but *lumen* diffused in a medium can generate a body — namely fire — by its multiplication: therefore *lumen* in a medium is a body.

*On the contrary:*

*Foundations.*

1. The Philosopher in the second of *On the Soul*[^6]: «*Lumen is neither a body nor an effluxion of a body*».

2. Likewise, this is seen by reason through its opposite. For darkness is opposed to *lumen* privatively[^7]: if therefore privation is not of body but of form, *lumen* is not a body but a form.

3. Likewise, this is seen by *motion*. For no body is moved suddenly according to place; but light alters suddenly, because in an instant it comes from east to west: therefore *lumen* is not a body. If you say that it is not moved suddenly but quickly [*repente*]; this cannot stand according to the Philosopher[^8], because if it were moved quickly — that is, imperceptibly in some space — in a larger space the succession could be sensed, as is clear in sound: therefore etc.

4. Likewise, no body is moved more swiftly than the body of the first movable, because that motion is the most perfect of all motions and therefore the swiftest[^9]; but *lumen* from east to west is moved much more swiftly than the first orb is moved, because light [moves] in an instant, and that [orb] at least in twelve hours: therefore *lumen* is not a body.

5. Likewise, no body is moved simultaneously and at once toward opposite parts[^10]; but *lumen* is simultaneously and at once moved toward opposite parts, because it is diffused upward and downward, before and behind, on the right and on the left: therefore it cannot be a body.

6. Likewise, it is impossible that two unmixed bodies which do not augment one another be simultaneously [in the same place]; but *lumen* is unmixed with the air, and does not augment the air itself, and yet is simultaneous [with it]: therefore it is not a body. That it is impossible for two bodies to be at once [in the same place], the Philosopher[^11] says, and for this there are reasons which can be omitted at present, since they are brought forward in the fourth [book], where the penetrability of the glorified body is treated.

7. Likewise, no body has its being in *continual coming-to-be*; but *lumen* in the air has its being in coming-to-be, because it continually goes forth from the sun, as Augustine says[^12]: therefore it is impossible that it be a body.

8. Likewise, if *lumen* is a body, either it is from something or it is from nothing. If from nothing, then it is by creation — therefore *lumen* is from God alone, since to create belongs to Him alone[^13]. If from something, I ask, from what? either from the body by which it is caused, or from the body in which it is received. It is established that not from the body in which it is received, because *lumen* is not produced out of the air — for then it could remain there when the sun withdraws. If from the body by which it is caused, then it seems that the luminous body, in the emission of *lumen*, loses something of its substance and matter, and thus it seems that by now the sun ought to be consumed.

### CONCLUSION.

> *Lumen and ray, as properly taken, is not a body.*

**I respond:** For the understanding of what has been said, it must be noted that on this matter there have been four opinions.

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*Opinion 1.* For some have wished to say that both *lumen* and ray in the medium is a *body*, and the going-out of the rays themselves from the sun is like the going-out of streams from a fountain. For just as from a fountain streams proceed, which are bodies and of the same nature as the fountain, so they say it is in the rays and the sun. And if you object to them that it seems that the substance of the sun and of other luminaries would by now be nearly consumed, they answer that, just as the substance of a fountain is not consumed — because as emission occurs, so also restoration occurs — so they say that the substance of the sun is not consumed, because just as outwardly downward it emits its *lumen*, so by the power of its rays it draws upward vapors to itself, by which it is restored, as a body by food — to such a degree that it neither fails nor decreases. And this Seneca[^14] seems to have held. — *It is disproven.* This position, however, is against philosophy, which says that celestial bodies are entirely incorruptible[^15].

*Opinion 2.* The second position, however, is that *lumen* is a *body*, and similarly the rays — and the procession of the rays themselves from the sun is like that of branches from a root, especially if it were so that the root could immediately produce a tree out of itself, assisted by divine power, as perhaps was the case in the first condition of things; and just as the root would not be diminished if it so produced a tree, and yet the branches would always be said to issue from that root — not because they go forth anew, but because they are continuous with their origin — so they say it is also in the sun's rays. For when God made the sun as the origin and principle of *lumen*, simultaneously with this He gave to it the ramification of rays; and the sun is continually said to emit those rays because those rays are never separated from their origin; but just as the sun is moved, so the rays are carried around — they are not generated anew; for the same rays which it emitted from the beginning upon the earth, it emits even now. — *It is disproven.* But suppose that the sun were darkened, as in the passion of Christ is believed to have happened[^16]; then it seems that it would have been necessary from then on for the rays to be renewed, and thus to be created anew, if they were bodies.

*Opinion 3.* The third position is that both *lumen* and ray in the medium is a *body*; and its production as regards *form* is from the sun, but as regards *matter* is from the Creator. For they say that this pertains to the perfection of the universe — that, just as there is some creature which as regards matter and form is immediately from God, like an angel; and some which as regards form is immediately from God and as regards matter is from nature, like man; so also there is a third genus, which as regards form is from a creature and as regards matter is from God. — *It is disproven.* But this does not seem probable, since God never creates matter apart from some form[^17].

Although, however, each of these three positions specifically says something improbable concerning the origin of *lumen* from light, nevertheless all of them are commonly disproven by this — that they say *lumen* in the medium to be a body — both on account of its diffusion, which is sudden; and also on account of its coexistence with the air, which is unmixed; and also on account of its production, which is neither from matter nor ever separated from its [source's] existence; rather, just as it continually is, so it is continually generated; as Augustine says[^18] that *lumen* has its permanence through the continual influence of the sun.

*Opinion 4 and conclusion.* And therefore there is a fourth position, in concord with reason and philosophy: that *lumen* and ray, if it names precisely that which has its rise from light, is neither a body nor an effluxion of a body, as the reasons adduced for this show. But if *ray* be called air illuminated according to *diameter*, and *lumen* air illuminated according to *depth*, then in this way ray and *lumen* can be called a body. — *Conclusion 2.* But as *lumen* and ray are properly taken in the medium, they are not a body.

*Solution of the opposing [arguments].*

1. To that which is first objected, that it is moved locally: it must be said that just as we see in a species generated from color that it is moved in two ways — and one motion is by diffusion, proceeding from the object body to the mirror, but the other motion [is] according as it seems to be moved in the mirror at the motion of the object body — and the first is not local motion, but [motion] of *generation*; but by the second motion it is not moved through itself, but per accidens — *Distinction.* so it must be understood in the matter at hand, that the motion of *lumen* which is by its going forth from the shining body is not properly local change, but rather the *generation* and *diffusion* of *lumen*; and this is clear from this — that it occurs suddenly in however great a space. — *Note.* The other motion, however, which is by the carrying of the rays themselves over the earth together with the sun itself — this is only per accidens, just as a power itself is moved at the motion of its influencing principle; and yet the power is not a body. So it must be understood of *lumen*, that it is related to the luminous body in the manner of an *influxed power*. Hence the Damascene[^19]: «*We say, on account of the lumen that proceeds from it, that fire shines; and we do not posit the lumen which is from it to be the ministerial organ of the fire, but rather a more natural power*».

2. To that which is objected, that the rays are reverberated from a body: it must be said that the reverberation of something from something can be in two ways. — *Twofold reverberation.* One, from the collision of two [bodies] meeting one another, as a ball is reverberated from a wall; another, from the ineptitude of the patient to receive the power of the agent — and thus a ray is reverberated from an opaque body. For the sun, or any other luminous body, has the power

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of diffusing *lumen* up to some determinate space, since it is of finite power; and as long as that power extends itself, *lumen* is multiplied, if there be a suitable receiver; — *Concerning perspective.* but when, before the termination of that power, some body meets [the ray] which is not suitable for its reception, by this very fact that *lumen* could not multiply itself further forward, it multiplies itself backward — not from the power of the resisting body, but from the power of the first mover. Hence, when reverberation of a ray occurs in water, with the water moved, the ray is moved — not because the water is the moving principle, but [because] the first power producing the ray, which, with occasion received from the water, could[^20] reflect the ray, and with occasion received from the same, can vary the reflection and thus move the ray. — As to what is said: *it is impossible for a non-body to be repelled by a body*[^21]; — *Distinction.* it must be said that if there is something so non-body that it be a spirit, this is true. But if it is so non-body that it nevertheless needs a body to carry it, then it can without doubt be repelled — as has been said in the case of *lumen*, and as is manifest in the image which shines back in a mirror because of the application of lead with glass, which is an opaque body. For if there were only the glass by itself, which is a pervious body, the species would pass through and would not return to the eye, as is clear by sensible experiment.

3. To that which is objected, that there occurs intersection[^22] and refraction of rays: it must be said that this is said by reason of the conjoined air, which by the power of the rays concurring there is subtilized and moved; and by reason of this the rays are also said to be refracted, when from the multiplication along opposite ways, by progression and regression, there occurs a certain multiplication and aggregation of light, and a subtilization of the air around a polished body — from which it happens that the heat-effect of the ray is intensified, and fire is generated in the same place through the intensification of heat from the air so subtilized.

4. To that which is objected, that *lumen* has the three dimensions in the medium: — *Distinction.* it must be said that something can have dimension in two ways: either from *itself*, or by reason *of that in which it is*. If from itself, then it is a body; if from elsewhere, it is not necessary. For so whiteness in white lead and snow has the three dimensions — [things] which are white inside and outside[^23].

5. To that which is objected, that if there were a vacuum around the sun, that it would illumine; — *On the vacuum and illumination.* it must be said that, although some have said this, it nevertheless does not seem true or probable. For the Philosopher holds the contrary in the second of *On the Soul*[^24], when he says that «*one does not see through a vacuum*»; and Augustine likewise in the twelfth book of the *Confessions*, in the beginning, says thus: «*Where would light be, if it were [there], unless it were present, surpassing in shining and illumining?*» — And there is also a reason against this — that, since *lumen* is a corporeal form, it needs a medium to carry it. And if you ask, what would impede [it]: I say that this is not on account of the presence of an impediment, but on account of the absence of help — just as if someone having great hunger and lacking food cannot eat, not because he is impeded, but because he is not helped.

6. To that which is objected, that *lumen* generates a body: — *Note.* it must be said that *lumen* does not act by its own power, but by the power of the luminous body; but the luminous body does not bring forth a body as regards matter, but only as regards form — and on this account, since *lumen* is that through which it acts, it is not necessary that *lumen* be a body, but it suffices that it be a corporeal form.

la: Vide supra pag. 317, nota 5. — Hoc arg., ut patet ex Aristot., II. de Anima, text. 70. (c. 7.), est Empedoclis (et Democriti). Cfr. etiam eiusdem liber de Sensu et sens. c. 3. Avicenna, de Anima seu Sexti Naturalium, p. III. c. 2. hoc et seq. arg. affert pro sententia dicentium, «*quod lumen, descendens ex lucido super corpora, non est qualitas, quae contingit eis, sed sunt corpora parvissima, separata a lucido corpore, circumquaque comitantia longitudinem lucidi, designata, quae moventur motu illius, et cum cadunt super corpora, illuminantur ex eis*». — In minori post *localiter* cod. X addit *et dimensive*.

en: See above p. 317, note 5. — This argument, as is clear from Aristotle, *On the Soul* II, text 70 (c. 7), is from Empedocles (and Democritus). Cf. also his book *On Sense and the Sensed*, c. 3. Avicenna, *On the Soul* or [book] of the *Sixth of the Naturalia*, p. III, c. 2, adduces this and the following argument for the opinion of those saying that «*lumen, descending from the luminous [body] upon bodies, is not a quality which happens to them, but [they] are very small bodies separated from the luminous body, accompanying the length of the luminous [body] all around, designated, which are moved by its motion, and when they fall upon bodies, [those bodies] are illumined from them*». — In the minor, after *localiter*, cod. X adds *et dimensive*.

la: In cod. I bene additur *ut dicit auctor Sex principiorum, c. 2. sive de Actione*.

en: In cod. I is well added *as the author of the* Six Principles *says, c. 2, or* On Action.

la: Aristot., IV. Phys. text. 8. (c. 1).

en: Aristotle, *Physics* IV, text 8 (c. 1).

la: Cod. T *existens*.

en: Cod. T [reads] *existens*.

la: Cfr. supra pag. 15, nota 11, ubi ex Aristot. affertur, quod *generans tale est, quale quod generatur*.

en: Cf. above p. 15, note 11, where from Aristotle it is adduced that *the one generating is such as the one generated*.

en: [*On the Soul* II,] text 69 (c. 7).

la: Ita codd. F Y aa, alii codd. cum Vat. *principaliter*, codd. R cc cum ed. 1 *Lumen enim opponitur tenebrae principaliter*. Aristot., II. de Anima text. 70. (c. 7.): *Videtur autem lumen contrarium esse tenebris; sunt autem tenebrae privatio* etc. — Quod privatio non sit corporis, sed formae, docet Aristot., I. Phys. text. 69. (c. 7.).

en: Thus codices F, Y, aa; other codices with the Vatican [edition read] *principaliter*; codd. R, cc with edition 1 [read] *For lumen is opposed to darkness principally*. Aristotle, *On the Soul* II, text 70 (c. 7): *Lumen seems to be contrary to darkness; but darkness is privation*, etc. — That privation is not of body but of form, Aristotle teaches, *Physics* I, text 69 (c. 7).

la: Libr. II. de Anima, text. 70. (c. 7.) iuxta translationem Arabico-latinam: *Et non vere dixit Empedocles neque alius, si aliquis dixit, sicut ipse dixit, quod lux transfertur et vadit in tempore inter terram et circumferentiam, sed imperceptibili a nobis. Iste enim sermo est extra verum et extra apparentiam; possibile est enim, hoc non percipi in brevi spatio, sed non percipi de oriente ad occidentem, magna est differentia valde* (μέγα λίαν τὸ αἴτημα). Cfr. etiam de Sensu et sens. c. 3. et 7. (c. 3. et 6.). — IV. Phys. text. 127. (c. 13.) Aristot. dicit: *Repente autem, quod in insensibili tempore propter parvitatem remotum est* (ἕκταν). — Vat. cum paucis tantum codd. omittit *hoc non potest stare secundum Philosophum, quia si repente*, et dein post *spatio* ipsa addit *tunc sequitur quod*.

en: [Aristotle,] *On the Soul* II, text 70 (c. 7) according to the Arabic-Latin translation: *And Empedocles did not speak truly — nor did anyone else, if anyone said as he said, that light is transferred and goes in [some] time between the earth and the circumference, but [in time] imperceptible to us. For this speech is outside the truth and outside appearance; for it is possible that this not be perceived in a brief space, but not perceived from east to west — there is a very great difference* (μέγα λίαν τὸ αἴτημα). Cf. also *On Sense and the Sensed*, c. 3 and 7 (c. 3 and 6). — *Physics* IV, text 127 (c. 13), Aristotle says: *But quickly [is that] which on account of its smallness is removed in insensible time* (ἕκταν). — The Vatican [edition] with only a few codices omits *hoc non potest stare secundum Philosophum, quia si repente*, and then after *spatio* itself adds *tunc sequitur quod*.

la: Cfr. supra pag. 19, nota 2.

en: Cf. above p. 19, note 2.

la: Vide Aristot., IV. Phys. text. 65. seqq. (c. 8.); VIII. text. 70. et 73. (c. 8.); et I. de Caelo et mundo, text. 5. seqq. et 77. (c. 2. 8.).

en: See Aristotle, *Physics* IV, text 65 and following (c. 8); VIII, text 70 and 73 (c. 8); and *On the Heavens and the World* I, text 5 and following, and 77 (c. 2, 8).

la: Libr. IV. Phys. text. 8. 47. 63. (c. 1. 6. 7.); III. de Caelo et mundo, text. 54. (c. 6.); I. de Gener. et corrupt. text. 32. 35. (c. 5.); II. de Anima, text. 69. (c. 7.). — Cfr. IV. Sent. d. 49. p. II. art. princ. 2. a. 3. q. 1. — Cod. cc et ed. 1 *inducentur* pro *inducuntur*, et dein post *quarto* in cod. F additur *libro, 49. dist*.

en: [Aristotle,] *Physics* IV, text 8, 47, 63 (c. 1, 6, 7); *On the Heavens and the World* III, text 54 (c. 6); *On Generation and Corruption* I, text 32, 35 (c. 5); *On the Soul* II, text 69 (c. 7). — Cf. IV *Sent.* d. 49, p. II, art. princ. 2, a. 3, q. 1. — Cod. cc and edition 1 [read] *inducentur* for *inducuntur*; and then after *quarto* in cod. F is added *libro, 49. dist*.

la: Libr. VIII. de Gen. ad lit. c. 12. n. 26. Vide tom. I. pag. 786, nota 9.

en: [Augustine,] *On Genesis according to the Letter* VIII, c. 12, n. 26. See volume I, p. 786, note 9.

la: Cfr. supra d. 7. p. II. a. 2. q. 2. in corp. — Aliquanto inferius cod. cc et ed. 1 *ex ipso aëre* pro *ex aere*.

en: Cf. above d. 7, p. II, a. 2, q. 2, in the body. — A little later cod. cc and edition 1 [read] *ex ipso aëre* for *ex aere*.

la: Libr. I. Natural. Quaest. c. 2. seqq.

en: [Seneca,] *Natural Questions* I, c. 2 and following.

la: Luc. 23, 45: *Et obscuratus est sol*.

en: Luke 23, 45: *And the sun was darkened*.

la: Supple cum ed. 1 *est*.

en: Supply with edition 1 *est*.

la: Libr. I. de Fide orthod. c. 8.

en: [John Damascene,] *On the Orthodox Faith* I, c. 8.

la: Vat. *poterit*.

en: The Vatican [edition reads] *poterit*.

la: Nonnulli codd. *moveri et repelli*. Dein cod. T *sic est verum* pro *hoc verum est*.

en: Some codices [read] *moveri et repelli*. Then cod. T [reads] *sic est verum* for *hoc verum est*.

la: Plurimi codd. cum edd. 1, 2 *intersectio*, licet in ipsa obiectione posuerint *intersecatio*.

en: Very many codices with editions 1, 2 [read] *intersectio*, although in the objection itself they put *intersecatio*.

la: Aristot., I. Ethic. c. 6: *Eadem in nive et cerussa albedinis ratio est*.

en: Aristotle, *Nicomachean Ethics* I, c. 6: *The account of whiteness in snow and in white lead is the same*.

latin_scholion:
Auctores vide supra in scholio ad a. 2. q. 1. — In 3. *fundam.* ex suppositione, quod motus luminis fiat in instante, concluditur, quod non sit corpus. Consentit S. Thom. (S. I. q. 67. a. 2.) his verbis: «*Si lumen esset corpus, illuminatio esset motus localis corporis. Nullus autem motus localis corporis potest esse in instanti… illuminatio autem fit in instanti*». — Quod autem *sonus* causetur motu locali, omnes tenebant (cfr. S. Thom., opusc. de Natura luminis). — Suppositio autem, quod motus luminis fiat in instante, falsa est, ut observationibus astronomicis nunc probatum est. Observandum autem est, quod S. Bonav., I. Sent. d. 37. p. II. a. 2. q. 3. ad 1. etiam aliam sententiam ut probabilem refert, quae tenet, motum illum fieri quidem in tempore imperceptibili, non autem instantaneo. — Quod autem non sit proprie motus *localis* ibi etiam sic explicatur, quod «*non est motus localis tantum, sed est motus diffusionis, qui est generatio, sicut generatur idolum ab obiecto; et quia lux simul est et lucet, simul cum est generat splendorem et ita in eodem instanti*» (cfr. hic ad 1. et infra d. 14. p. I. a. 3. q. 2. ad 3.). — De quaestione, utrum lumen moveatur in instante, integra quaestione disputat Richard. a Med. (hic a. 2. q. 2.) et in fine concludit, affirmativam sententiam magis esse consonam Philosopho magisque sibi placere.

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english_scholion:
See the authors above in the scholion to a. 2, q. 1. — In *fundamentum* 3, from the supposition that the motion of *lumen* occurs in an instant, it is concluded that it is not a body. S. Thomas agrees (S. I, q. 67, a. 2) in these words: «*If lumen were a body, illumination would be a local motion of a body. But no local motion of a body can be in an instant… but illumination occurs in an instant*». — That *sound*, however, is caused by local motion, all held (cf. S. Thom., *opusc. de Natura luminis*). — The supposition, however, that the motion of *lumen* occurs in an instant, is false, as has now been proved by astronomical observations. It must, however, be observed that S. Bonav., I *Sent.* d. 37, p. II, a. 2, q. 3, *ad* 1, also reports another opinion as probable, which holds that that motion does occur in an imperceptible time, not however in an instantaneous [one]. — That, however, it is not properly local motion is also explained there thus, that «*it is not local motion only, but is the motion of diffusion, which is generation — just as an idol is generated from the object; and because light at the same time both is and shines, at the same time as it is, it generates splendor, and so in the same instant*» (cf. here *ad* 1, and below d. 14, p. I, a. 3, q. 2, *ad* 3). — On the question whether *lumen* is moved in an instant, Richard of Mediavilla disputes in an integral question (here a. 2, q. 2), and at the end concludes that the affirmative opinion is more consonant with the Philosopher and more pleasing to himself.

---

translators_notes:
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- **Scholion**: single paragraph at p.326 R bottom (no per-item enumeration). Cross-references S. Thomas's parallel argument from S. I q. 67 a. 2 (instantaneous illumination → not corporeal motion → not body), notes that the instantaneous-motion supposition has been falsified by 19th-cent. astronomy, points out that S. Bonav. himself elsewhere (I Sent. d. 37, p. II, a. 2, q. 3, *ad* 1) reports a probable alternative — motion in imperceptible time, not instantaneous — and refers to Richard of Mediavilla's integral question (here a. 2, q. 2) which concludes that the affirmative (instantaneous) is more consonant with the Philosopher.
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method: LLM-assisted translation from the Quaracchi Latin, verified chunk-by-chunk against the printed plates (apparatus roster, cross-references, page/gutter boundaries).

license_source: Public Domain Mark 1.0

license_translation: CC BY-NC 4.0

license_apparatus: CC BY-NC 4.0


title: Dist. 13, Art. 3, Q. 2

source_text:
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### Quaestio II. *Utrum lumen sit forma substantialis, an accidentalis.*

Secundo quaeritur, utrum *lumen* sit forma substantialis, vel accidentalis. Et quod sit forma accidentalis, videtur.

*Fundamenta.*

1. Quod advenit iam completo *in esse* est accidentale[^1]; sed lumen advenit aëri iam completo in esse: ergo est accidentale.

2. Item, «*quod adest et abest praeter subiecti corruptionem, est accidens*[^2]»; lumen adest et abest praeter aëris corruptionem, quod est subiectum eius: ergo etc.

3. Item, sicut se habet color ad corpus terminatum, ita se habet lumen ad corpus transparens[^3]; sed color est accidens in corpore terminato: ergo lumen est accidens in corpore transparenti.

4. Item, si unum oppositorum, in subiecto existens, est accidens, et reliquum est accidens[^4]; sed obnubilatio accidit ipsi aëri: ergo pari ratione et illuminatio.

*Ad oppositum:*

1. Impossibile est, duo accidentia eiusdem speciei esse in eodem subiecto, quia accidens numeratur per subiectum, in quo est: sed duo lumina, sicut dicit Dionysius[^5], sunt in eodem aëris medio: ergo impossibile est, lumen esse accidens aëris.

2. Item, accidens cum generatur, ex propriis principiis subiecti habet ortum, et cum resolvitur, resolvitur in suum subiectum[^6]; sed lumen nec educitur ex aëre nec resolvitur in aërem: ergo lumen non est accidens aëris. Et constat, quod est in aëre: ergo si eius non est accidens, nullius est accidens.

3. Item, nullum accidens transit a subiecto in subiectum[^7]; sed radius mutatur ab una parte aëris in aliam, et lumen similiter: ergo lumen accidens esse non potest.

4. Item, nullum accidens manet immobile, moto eo in quo est[^8]; sed radius manet immobilis, moto aëre: ergo radius accidens non est. Si tu dicas, hoc esse propter hoc, quod lumen in medio habet *esse spirituale*, sicut idolum[^9]; obiicitur contra hoc, quia radius et lumen habet ibi operationem naturalem et principium operationis naturalis: ergo videtur, quod sit ibi *naturaliter* et concrete, non *spiritualiter* et abstracte.

### CONCLUSIO.

> *Lumen in medio, quatenus dicit vim activam, dicit substantiam, habentem modum accidentis; quatenus dicit qualitatem sensibilem, dicit accidens, quod non plene habet rationem accidentis naturalis, sed similitudinis vel intentionis.*

**Respondeo:** Ad praedictorum intelligentiam est notandum, quod circa hoc triplex est modus dicendi, quorum quilibet supponit, lumen in medio esse formam, sive qualitatem aliquam.

*Opinio 1.* Quidam enim dicunt, quod lumen in medio est *substantia*; existit tamen in medio *per modum accidentis*, quia non est ipsi aëri substantialis; et hoc dicunt propter hoc, quod generatio luminis a luce est secundum viam univocationis[^10]; et ideo, cum lux sit forma substantialis in suo fonte, dicunt, lumen substantiam esse *in medio*, licet modum essendi habeat accidentalem, maxime cum luminis et lucis non videatur alia essentia esse, sed solummodo differre videantur per modum essendi sive per *esse*.

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Sed quia lumen in medio est illud quod *Opinio 2.* potissime sentitur et facit alia sentiri[^11]; ideo est secunda positio, quod lumen in medio est *accidens*; non enim causatur a corpore luminoso, nisi in quantum fulgidum est; et ita est accidens per comparationem ad *principium a quo*. Dicunt etiam, quod est accidens per comparationem ad *subiectum in quo*, quia advenit iam completo et potest adesse et abesse praeter subiecti corruptionem; et ita plenam rationem accidentis habet lumen in medio, non tamen per comparationem ad idem. Accidens enim habet comparari ad substantiam sicut ad *subiectum* et *causam*; lumen vero, etsi his duobus modis habeat comparari ad substantiam, non tamen ad eandem, quia ad aërem comparatur sicut ad subiectum, quia est in illo; ad corpus luminosum, sicut ad principium, quia est ab illo[^12].

Sed quia lumen, prout est in medio existens, habet se ipso sentiri, ita quod positum supra sensum sensum facit; et iterum, in eadem parte medii habet sine confusione multiplicari, secundum positionem Dionysii: ideo est *Opinio 3.* tertia positio, quod lumen in medio nec est substantia nec est accidens proprie, quia non habet ibi *esse naturale* et materiae concretum, sed *spirituale* et abstractum. Unde dicunt, quod sicut comparatur species coloris in medio ad colorem existentem in corpore obiecto; sic lumen in medio ad lucem existentem in corpore luminoso. — *Improbatur.* Sed cum lumen in medio non solum habeat operationem *spiritualem* in animam, sed etiam *naturalem* in corpora naturalia; non solum videtur esse in aëre per modum spiritualem, sive esse ibi per modum habitus, sed etiam aliquo modo secundum esse naturale; et ita videtur, quod illud non sufficiat dicere, quamvis videatur esse valde verisimile.

*Iudicium de praedictis.* Propterea intelligendum est, quod omnes modi praedicti aliquid veritatis in se continent, et ex omnibus his elicitur una veritas integra; quod patet sic. — *Lumen dicit 1. virtutem activam.* Lumen enim in medio dicit *virtutem activam*, egredientem a corpore luminoso, per quam corpus luminosum agit et imprimit in haec inferiora; et haec est virtus substantialis ipsi corpori[^13]. Et de hac dicit Damascenus, quod lumen, quod est ex igne, non est aliquid ministeriale ipsius ignis vel accidentale, sed virtus ei connaturalis et consubstantialis, sicut patet in auctoritate inducta in praecedenti problemate[^14]; et haec virtus non est sensu perceptibilis nec solummodo operatur in sensu visus, sed etiam facit ad eductionem omnium sensuum in actum, sicut dicit Augustinus septimo super Genesim ad litteram[^15], quod habitum est in quadam auctoritate prius inducta. Sic etiam dicunt philosophi, quod corpus caeleste mediante suo lumine influit usque ad profundum terrae, ubi mineralia corpora generari habent. Et quantum ad hoc verum dicunt qui dicunt, quod *lumen dicit substantiam accidentaliter ad aërem comparatam*, sicut virtus agentis ad deferens quodammodo accidentaliter comparatur.

*2. qualitatem sensibilem.* Non solum autem lumen dicit illam vim activam, quam non percipit sensus, sed etiam quandam *qualitatem sensibilem*, qua sensus visus efficitur sentiens in actu; et illa est qualitas accidentalis in tertia specie qualitatis. Et secundum hoc dicit Avicenna in libro de Sufficientia naturali[^16], quod «*lumen est affectio corporis habentis lucem, cum oppositum fuerit illi*», scilicet pervium. Et sic verum dicebat illa secunda opinio, quae dicebat, lumen esse *accidens*, non solum per comparationem ad aërem, in quo recipitur, sed etiam in comparatione ad corpus, a quo causatur, quia ab ipso oritur, in quantum illud[^17] est fulgidum et habet esse obiectum sensus.

*Notandum.* Secundum autem utramque istarum naturarum in lumine repertarum lumen ad aërem comparatur, non sicut ad *primum subiectum*, sed sicut ad *deferens* et ad *medium*; et ideo per comparationem ad ipsum aërem non habet modum existendi *naturalem*, sed per modum *habitus*; nec est forma naturalis, sed potius similitudo eius; sicut species[^18] in medio non est *proprie color*, sed *ut color* sive similitudo coloris. Maximam tamen habet approximationem ad illum; et adeo illi innititur, ut non indigeat principio extrinseco, ex quo educatur. Unde lumen in medio non habet principium materiale

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ex quo, sed potius originale, a quo fluit et ad quod etiam redit, cum in medio desinit esse, sicut dicitur de similitudine. Et hoc modo dicit Commentator super secundum de Anima[^19], quod *lux* est habitus diaphani, et quod est in ipso, sicut intentio vel species vel similitudo. Et quartum ad hoc verum dicebat tertia opinio.

*Conclusio de membris.* Ex his igitur patet, quod lumen in medio, in quantum dicit *vim activam*, dicit *substantiam*, habentem modum *accidentis*; in quantum dicit *qualitatem sensibilem*, dicit *accidens*. Sed accidens illud relatum ad aërem non habet plene rationem *accidentis naturalis*, sed similitudinis vel intentionis, quia est ibi non sicut in subiecto sustinente, sed sicut in deferente[^20]. — Ex his patent rationes ad utramque partem.

*Ad fundamenta.*

*1. 2.* Quod enim obiicitur, quod advenit iam completo et recedit[^21] praeter subiecti corruptionem, hoc ostendit, quod habet *modum accidentis*, secundum quod est in medio.

*3. 4.* Quod vero obiicit, quod se habet ad modum coloris et est qualitas sensibilis; de lumine loquitur, secundum quod in se habet *naturam accidentis*.

*Ad opposita.* Rationes vero ad oppositum, quae probant, quod non sit *accidens*, quia non numeratur a numeratione subiecti, quia non movetur ad motum aëris, quia non causatur ab aëre nec resolvitur in aërem; concludunt solum, quod non habet ibi *plene rationem accidentis naturalis*, *De accidente naturali.* quod comparatur ad illud, in quo est, sicut ad subiectum et causam, et quod etiam sustinetur et dependet ab eo, in quo est, principaliter et ei coniungitur inseparabili vinculo. — *De lumine ut accidente.* Hoc autem non est in proposito, quia lumen, quamvis sit in aëre, causatur a corpore luminoso et ab illo principaliter dependet; nec est in aëre sicut in sustinente, sed sicut in deferente; et ideo durationem et mutationem et numerationem potius recipit a *lucido influente* quam ab *aëre suscipiente*. Et ob hoc dicit Dionysius[^22], plura lumina esse in eodem medio inconfusa et convelli sive separari ab invicem secundum absentationem corporum illuminantium. Distinctio enim illa est propter continuationem luminum cum sua origine, a qua procedunt naturaliter et virtute eius agunt, quamvis in medio sint quodam modo *spiritualiter* et abstracte. Et sic cetera circa hoc quaesita iam patent.

english:
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### Question II. *Whether lumen is a substantial form or an accidental one.*

Secondly it is asked whether *lumen* is a substantial form or an accidental one. And that it is an accidental form is shown.

*Fundamenta.*

1. That which comes upon something already complete *in being* is accidental[^1]; but lumen comes upon air already complete in being: therefore it is accidental.

2. Likewise, «*that which is present and absent apart from the corruption of the subject is an accident*[^2]»; lumen is present and absent apart from the corruption of the air, which is its subject: therefore etc.

3. Likewise, as color stands to a terminated body, so lumen stands to a transparent body[^3]; but color is an accident in the terminated body: therefore lumen is an accident in the transparent body.

4. Likewise, if one of opposites, existing in a subject, is an accident, the other is also an accident[^4]; but obscuration happens to air itself: therefore by parity of reasoning so does illumination.

*To the contrary:*

1. It is impossible that two accidents of the same species be in the same subject, because an accident is numbered by the subject in which it is: but two *lumina*, as Dionysius[^5] says, are in the same air medium: therefore it is impossible that lumen be an accident of the air.

2. Likewise, an accident, when it is generated, has its origin from the proper principles of the subject, and when it is resolved, is resolved into its subject[^6]; but lumen is neither educed out of air nor resolved into air: therefore lumen is not an accident of air. And it is settled that it is in air: therefore if it is not an accident of it, it is an accident of nothing.

3. Likewise, no accident passes from subject to subject[^7]; but a ray is transferred from one part of air to another, and lumen likewise: therefore lumen cannot be an accident.

4. Likewise, no accident remains immobile when that in which it is is moved[^8]; but a ray remains immobile when the air is moved: therefore the ray is not an accident. If you say this is because lumen in the medium has *spiritual being*, like an idolum[^9]; against this it is objected that ray and lumen there have natural operation and the principle of a natural operation: therefore it seems that it is there *naturally* and concretely, not *spiritually* and abstractly.

### CONCLUSION.

> *Lumen in the medium, insofar as it denotes an active power, denotes a substance having the mode of an accident; insofar as it denotes a sensible quality, it denotes an accident — one which does not fully have the character of a natural accident, but [the character] of a likeness or intention.*

**I respond:** For the understanding of the foregoing it is to be noted that on this point there is a threefold way of speaking, each of which presupposes that lumen in the medium is some form or quality.

*Opinion 1.* For some say that lumen in the medium is a *substance*; yet it exists in the medium *by the mode of an accident*, because it is not substantial to the air itself; and they say this because the generation of lumen from lux is by the way of univocation[^10]; and so, since lux is a substantial form in its source, they say that lumen is a substance *in the medium*, although it has an accidental mode of being — especially since there does not seem to be any other essence belonging to lumen and lux, but only that they seem to differ by mode of being or by *esse*.

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But because lumen in the medium is that which *Opinion 2.* is most especially sensed and which makes other things to be sensed[^11]; therefore there is a second position, that lumen in the medium is an *accident*; for it is not caused by the luminous body except insofar as it is shining; and so it is an accident by comparison to the *principle from which*. They also say that it is an accident by comparison to the *subject in which*, because it comes upon [something] already complete and can be present and absent apart from the corruption of the subject; and thus lumen in the medium has the full character of an accident, though not by comparison to the same [term]. For an accident is wont to be compared to a substance as to *subject* and *cause*; but lumen, although it has to be compared to substance in these two modes, [is compared] not to the same one, because it is compared to air as to subject, since it is in it; to the luminous body, as to principle, since it is from it[^12].

But because lumen, insofar as it exists in the medium, is sensed of itself, so that, placed before the sense, it makes [it] sense; and again, in the same part of the medium it can be multiplied without confusion, according to the position of Dionysius: therefore there is a *Opinion 3.* third position, that lumen in the medium is neither substance nor accident properly, because it does not have there *natural being* concrete with matter, but *spiritual* and abstract [being]. Hence they say that, just as the species of color in the medium is compared to the color existing in the object body, so lumen in the medium [is compared] to the lux existing in the luminous body. — *Improbatur.* But since lumen in the medium has not only a *spiritual* operation upon the soul but also a *natural* one upon natural bodies, it seems to be in the air not only in a spiritual mode (i.e. to be there by the mode of a habit) but also in some way according to natural being; and so it seems that this is not enough to say, although it seems very probable.

*Judgement on the foregoing.* Therefore it is to be understood that all the above ways contain something of truth in themselves, and from all these one integral truth is elicited; which is clear thus. — *Lumen denotes 1. an active power.* For lumen in the medium denotes an *active power*, going forth from the luminous body, by which the luminous body acts and impresses upon these lower things; and this is a power substantial to the body itself[^13]. And of this Damascene says that lumen, which is from fire, is not something ministerial to fire itself or accidental, but a power connatural and consubstantial to it, as is clear in the authority adduced in the preceding problem[^14]; and this power is not perceptible by sense, nor does it operate only in the sense of sight, but it also conduces to the eduction of all the senses into act, as Augustine says in the seventh [book] *On Genesis according to the Letter*[^15], which was held in a certain authority previously adduced. Thus also the philosophers say that the celestial body, by means of its lumen, influences down to the depths of the earth, where mineral bodies are wont to be generated. And as to this, those say truly who say that *lumen denotes substance accidentally compared to air*, just as the power of an agent is in a certain way accidentally compared to that which carries [it].

*2. a sensible quality.* But lumen denotes not only that active power, which sense does not perceive, but also a certain *sensible quality*, by which the sense of sight is made actually sensing; and that is an accidental quality in the third species of quality. And accordingly Avicenna says in the book *On the Natural Sufficiency*[^16] that «*lumen is an affection of a body having lux, when its opposite is present to it*», namely the pervious. And so that second opinion was speaking truly, which said that lumen is an *accident*, not only by comparison to the air in which it is received, but also in comparison to the body by which it is caused, since it arises from it inasmuch as that[^17] is shining and has being as an object of sense.

*Notandum.* According to each of these natures found in lumen, lumen is compared to the air not as to a *first subject*, but as to a *carrier* and to a *medium*; and therefore by comparison to the air itself it does not have a *natural* mode of existing, but [exists] by the mode of a *habit*; nor is it a natural form, but rather a likeness of one; just as a species[^18] in the medium is not *properly color*, but *as color* or a likeness of color. Yet it has the maximum approximation to it; and it rests upon it so closely that it does not need an extrinsic principle out of which it may be educed. Hence lumen in the medium does not have a material principle

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out of which, but rather an originative one, from which it flows and to which it also returns when it ceases to be in the medium, as is said of a likeness. And in this way the Commentator on the second [book] *On the Soul*[^19] says that *lux* is the habit of the diaphanous, and that it is in it as intention or species or likeness. And as to this fourth point the third opinion was speaking truly.

*Conclusion as to the members.* From these things, therefore, it is clear that lumen in the medium, insofar as it denotes *active power*, denotes *substance* having the mode of *accident*; insofar as it denotes *sensible quality*, it denotes *accident*. But that accident, referred to air, does not fully have the character of a *natural accident*, but [that] of a likeness or intention, because it is there not as in a sustaining subject, but as in a carrier[^20]. — From these things the answers to both sides are clear.

*To the fundamenta.*

*1. 2.* As for the objection that it comes upon [something] already complete and recedes[^21] apart from the corruption of the subject, this shows that it has the *mode of an accident*, according as it is in the medium.

*3. 4.* As for the objection that it stands in the mode of color and is a sensible quality, this speaks of lumen according as it has in itself the *nature of an accident*.

*To the contrary [arguments].* The reasons on the contrary, which prove that it is not an *accident* — because it is not numbered by the numbering of the subject, because it is not moved at the motion of the air, because it is not caused by the air nor resolved into the air — conclude only that it does not there have *fully the character of a natural accident*; *On the natural accident.* which is compared to that in which it is as to subject and cause, and which is also sustained and depends upon that in which it is principally and is joined to it by an inseparable bond. — *On lumen as accident.* But this is not the case in the matter at hand, because lumen, although it is in air, is caused by the luminous body and depends upon it principally; nor is it in air as in a sustainer, but as in a carrier; and therefore it receives duration and change and numbering rather from the *lucid [body] which influences* than from the *air which receives*. And on this account Dionysius[^22] says that many *lumina* are in the same medium unconfused, and are torn apart or separated from one another according to the withdrawal of the illuminating bodies. For that distinction is owing to the continuation of the *lumina* with their origin, from which they proceed naturally and by whose power they act, although in the medium they are in a certain way *spiritually* and abstractly. And thus the other things asked about this matter are now clear.

la: Averroes, *de Substantia orbis*, c. 1. (sive Prologus): «*Est dispositio in omnibus accidentibus in prima materia, scil. quod non inveniuntur in ea, nisi secundum quod habet formam existentem in actu*». Et super II. de Anima, text. 4: *Subiectum enim accidentis est corpus compositum ex materia et forma, et est aliud existens in actu et non indiget in suo* esse *accidenti*.

en: Averroes, *On the Substance of the Orb*, c. 1 (or *Prologue*): «*There is a disposition in all accidents in prime matter, namely that they are not found in it except according as it has a form existing in act*». And on *On the Soul* II, text 4: *For the subject of an accident is a body composed of matter and form, and it is something else existing in act and does not need an accident for its* esse.

la: Porphyr., *de Praedicab.* c. *de Accidente*, secundum Aristot., I. Topic. c. 4.

en: Porphyry, *On the Predicables*, chapter *On the Accident*, according to Aristotle, *Topics* I, c. 4.

la: Vide supra pag. 320, nota 5.

en: See above p. 320, note 5.

la: Simile occurrit in Aristot., I. Topic. c. 13, qui hanc regulam generalem statuit: *Quot modis dicitur unum oppositorum, tot modis dicitur et reliquum*.

en: A similar thing occurs in Aristotle, *Topics* I, c. 13, who lays down this general rule: *In as many modes as one of opposites is said, in so many is the other also said*.

la: *De Div. Nom.* c. 2. § 4. Vide supra pag. 119, nota 9. — De maiori cfr. ibid. nota 8.

en: [Dionysius,] *On the Divine Names*, c. 2, § 4. See above p. 119, note 9. — On the major [premise] cf. ibid. note 8.

la: Pro hac propositione allegatur Aristot., I. Phys. text. 80. (c. 9.): «*Permanens enim materia cum forma causa est eorum quae fiunt, sicut mater*». Et VII. Metaph. text. 3. seqq. (VI. c. 1.), ubi agit de relatione accidentium ad substantiam substantiaeque attribuit prioritatem respectu accidentium. In versione Arabico-latina, loc. cit. text. 3, legitur: «*Manifestum est igitur, quod haec [substantia] est causa essentiae cuiuslibet illorum [accidentium], et illa sunt propter istam*». Idem ait Averroes ibid. — Sententia Boethii, *Dialog.* II; IV. et V. Comment. in Porphyr. (*de Communit. et different. speciei, proprii et accidentis*) in has redacta est propositiones: *proprium consequitur principia speciei et causatur ex ipsis: accidens vero, sive sit separabile sive sit inseparabile, consequitur principia individui et causatur ex ipsis*. «*Haec enim [individua], generationi et corruptioni supposita, variis semper accidentibus permutantur*».

en: For this proposition Aristotle is adduced, *Physics* I, text 80 (c. 9): «*For matter remaining with form is the cause of things which come to be, as mother*». And *Metaphysics* VII, text 3 and following (VI, c. 1), where he treats of the relation of accidents to substance and attributes priority to substance with respect to accidents. In the Arabic-Latin version, loc. cit., text 3, it reads: «*It is therefore manifest that this [substance] is the cause of the essence of each of those [accidents], and those are on account of this*». Averroes says the same, ibid. — The opinion of Boethius (*Dialog.* II; IV and V *Comment. in Porphyr.*, *On the Community and difference of species, of the proper and of the accident*) has been reduced to these propositions: *the proper follows the principles of the species and is caused by them; the accident, however, whether it be separable or inseparable, follows the principles of the individual and is caused by them*. «*For these [individuals], subjected to generation and corruption, are always changed by various accidents*».

la: Boeth., I. *Comment. in Categorias seu Praedicam. Aristotelis*. Verba vide tom. I. pag. 162, nota 11.

en: Boethius, I *Commentary on the Categories or Predicaments of Aristotle*. For the words, see volume I, p. 162, note 11.

la: Sub hoc respectu ait Aristot., II. Topic. c. 3. (c. 7.): *Nam motis nobis, necessarium est, et quae in nobis sunt omnia simul moveri*. Cfr. IV. Phys. text. 32. (c. 4.), ubi docet, accidentia moveri non posse per se, sed per accidens, i. e. moto subiecto, in quo sunt.

en: Under this aspect Aristotle, *Topics* II, c. 3 (c. 7) says: *For when we are moved, it is necessary that those things also which are in us all be moved together*. Cf. *Physics* IV, text 32 (c. 4), where he teaches that accidents cannot be moved per se but per accidens, i.e. when the subject in which they are is moved.

la: Cfr. supra pag. 83, nota 1. — Mox Vat. voci *principium* praemittit *est*.

en: Cf. above p. 83, note 1. — Then the Vatican [edition] prefixes *est* to the word *principium*.

la: Secundum Aristot., VII. Metaph. text. 30. seqq. (VI. c. 9.), ut substantia generetur, «*necesse est, praeexistere semper aliam substantiam actu existentem, quae facit, ut puta animal, si animal fit*», scil. eiusdem speciei (univocam). Cfr. supra pag. 15, nota 11.

en: According to Aristotle, *Metaphysics* VII, text 30 and following (VI, c. 9), in order that a substance be generated, «*it is necessary that there always pre-exist another substance existing in act, which makes, for instance, an animal, if an animal comes to be*», namely of the same species (univocal). Cf. above p. 15, note 11.

la: Nulla siquidem substantia per sensum cognoscitur, sed solum accidens. Cfr. supra a. 2. q. 2. arg. 2. ad opp.

en: Indeed no substance is known by sense, but only an accident. Cf. above a. 2, q. 2, arg. 2, ad opp.

la: Avicenna, *de Anima* sive *Sexto Naturalium*, p. III. c. 3. ait: «*Lux enim est qualitas, quae ex sua essentia est perfectio translucentis, secundum quod est translucens; est etiam aliqua qualitas in eo, quod est visibile ex sua essentia et non per aliud… Lumen vero est qualitas, quam mutat corpus non translucens a lucido, et translucens efficitur per eam translucens in effectu*». — Ad pleniorem intelligentiam eorum, quae mox de lumine dicuntur, notandum, quod S. Doctor ibi respicit ea, quae ad sensationem eliciendam requiruntur. Sub quo respectu Aristot., II. de Anima, text. 73. (c. 7.), de colore dicit: *Nunc autem in tantum manifestum est, quod id quidem quod in lumine videtur color est; unde non videtur sine lumine; hoc enim erat ipsi colori esse motivum esse secundum actum perspicui. Actus autem perspicui lumen est. Signum autem huius manifestum; si quis enim ponat id quod habet colorem, super ipsum visum, non videbit; sed color quidem movet perspicuum, puta aërem; ab hoc autem, continuo existente, movetur sensorium*.

en: Avicenna, *On the Soul* or [book] of the *Sixth of the Naturalia*, p. III, c. 3, says: «*For lux is a quality which from its essence is the perfection of the translucent, insofar as it is translucent; there is also some quality in that which is visible from its own essence and not through another… But lumen is a quality which a non-translucent body changes from a lucid [body], and the translucent is made through it to be actually translucent*». — For a fuller understanding of what is soon said of lumen, it is to be noted that S. Doctor there has in view those things which are required for the eliciting of sensation. Under which respect Aristotle, *On the Soul* II, text 73 (c. 7), says of color: *But now it is manifest to this extent, that that which is seen in lumen is color; whence it is not seen without lumen; for this was for color itself to be moving according to the act of the perspicuous. But the act of the perspicuous is lumen. The sign of this is manifest: for if anyone places that which has color upon the sight itself, he will not see; but color does move the perspicuous, e.g. the air; and from this, being continuous, the sensorium is moved*.

la: Ex codd. A W Y bb cc supplevimus *secundum*.

en: From codd. A, W, Y, bb, cc we supplied *secundum*.

la: In cod. I additur *luminoso*.

en: In cod. I is added *luminoso*.

la: In solutione ad 1. obiectum.

en: In the solution to the first objection.

la: Cap. 15. n. 21. et c. 19. n. 25. Cfr. supra a. 2. q. 2. arg. 2. ad opp., ubi XII. de Gen. ad lit. c. 16. n. 32. citatur. — De generatione lapidum et metallorum vide B. Albert., I. *de Mineral.* tr. 1. c. 4. seqq. et III. tr. 1. c. 3. et c. 10, ubi diversae opiniones philosophorum hac de re recensentur.

en: [Augustine, *On Genesis according to the Letter* VII,] c. 15, n. 21 and c. 19, n. 25. Cf. above a. 2, q. 2, arg. 2, ad opp., where *On Genesis according to the Letter* XII, c. 16, n. 32 is cited. — On the generation of stones and metals see B. Albert, I *On Minerals*, tr. 1, c. 4 and following, and III, tr. 1, c. 3 and c. 10, where various opinions of philosophers on this matter are recounted.

la: Distinctius: in libro *de Anima*, qui *Sextus Naturalium* dicitur, p. III. c. 1. — De tertia qualitatis specie, XIII. passione et qualitate patibili, cuius paulo superius mentio fit, cfr. supra pag. 229, nota 7.

en: More distinctly: in the book *On the Soul*, which is called *Sixth of the Naturalia*, p. III, c. 1. — On the third species of quality, the XIII passion and patible quality, of which mention is made a little above, cf. above p. 229, note 7.

la: Plures codd. cum ed. 1 *ipsum*.

en: Several codices with edition 1 [read] *ipsum*.

la: Vat. *sed potius similitudo eius, scilicet lucis, sic species coloris in medio* etc., quae et paulo inferius substituit *principio intrinseco* pro *principio extrinseco*.

en: The Vatican [edition reads] *sed potius similitudo eius, scilicet lucis, sic species coloris in medio*, etc., which also a little later substitutes *principio intrinseco* for *principio extrinseco*.

la: Text. 70. (c. 7.): *Lux non est corpus, sed est praesentia* intentionis *in diaphano, cuius privatio dicitur obscuritas apud praesentiam corporis luminosi. Et hoc quod dixit [Aristoteles] manifestum est, quoniam subiectum obscuritatis et lucis est corpus et est diaphanum, et lux est forma et* habitus *huius corporis; et si esset corpus, tunc corpus penetraret corpus*.

en: [Averroes, on *On the Soul* II,] text 70 (c. 7): *Lux is not a body, but is the presence of an* intentio *in the diaphanous, the privation of which is called darkness in the presence of a luminous body. And this which [Aristotle] said is manifest, since the subject of darkness and of lux is body and is diaphanous, and lux is a form and* habit *of this body; and if it were a body, then body would penetrate body*.

la: Hanc distinctionem insinuat Aristot., II. de Anima, text. 76. (c. 7.), in cuius expositione Averroes ait: *Color habet duplex esse, quorum unum est in diaphano non terminato, et est illud in quo est extraneum; et aliud in diaphano terminato, et est esse eius naturale*.

en: Aristotle suggests this distinction, *On the Soul* II, text 76 (c. 7), on whose exposition Averroes says: *Color has a twofold being, of which one is in the unterminated diaphanous, and is that in which it is extraneous; and the other in the terminated diaphanous, and is its natural being*.

la: Cod. O *et potest adesse et abesse* pro *et recedit*. Vat. post *completo* addit *in esse*, cod. T *est accidens*.

en: Cod. O [reads] *et potest adesse et abesse* for *et recedit*. The Vatican [edition] after *completo* adds *in esse*; cod. T [reads] *est accidens*.

latin_scholion:
**I.** Hic agitur de lumine, inquantum est in medio, non in corpore luminoso. S. Bonav. hoc iterum dupliciter distinguit, scil. quatenus est *virtus activa*, non sensibilis, quae multiplicem actionem habet in hunc mundum corporeum et egreditur a corpore luminoso, cui est consubstantialis; et quatenus est phaenomenon visibile et *accidentalis qualitas sensibilis*. De natura huius qualitatis dissentiunt Scholastici, cum «*distinguatur qualitas in qualitatem sensibilem, et in qualitatem, quae est species sive intentio qualitatis sensibilis*» (Scot. hic q. unica, n. 3.). Controvertitur autem, utrum lumen sensibile sit qualitas *intentionalis* et non *naturalis*, an *naturalis* et non *intentionalis*, an formaliter tum naturalis tum intentionalis. Quae controversia ut melius intelligatur, duo praenotamus.

*1.* Quoad *sensum* termini *intentio* Scot. (II. Report. hic q. unica n. 4.) dicit: «*Nomen* intentio *aequivocum uno modo dicitur actus voluntatis; secundo, ratio formalis in re, sicut intentio rei, a qua accipitur* genus, *differt ab intentione, a qua accipitur* differentia; *tertio modo dicitur* conceptus; *quarto, ratio tendendi in obiectum, sicut similitudo dicitur ratio tendendi in illud cuius est. Et isto modo dicitur* lumen *intentio vel species lucis*».

*2.* Scholastici communiter loquuntur de duabus generationibus formarum, quae experientia comprobantur, scil. formarum *realium*, quae in generatione educuntur de potentia materiae, et *intentionalium*, quae non educuntur de potentia materiae. De differentia et similitudine utriusque generationis plura profert Aegid. R. (hic q. 2. a. 2. et dub. lat.). — De utraque generatione loquitur S. Bonav. mira subtilitate in Hexaëm. Serm. II, ubi distinguit duodecim generationes, quarum quatuor fiunt per *diffusionem*, quatuor per *expressionem*, quatuor per *propagationem*. Inter generationes per diffusionem primo loco ponit generationem *splendoris a luce*, inter generationes autem per expressionem generationem *speciei ab obiecto*, de qua dicit: «*Et hoc est mirabile, quomodo species generatur, quia non de materia aëris, quia, cum non dicat essentiam, sed* modum essendi, *sufficit, ut habeat principium* originativum, *medium inter principium materiale et principium effectivum. Unde Deus dedit virtutem cuilibet rei, ut gigneret similitudinem suam ex naturali fecunditate. Unde secundum quod obiectum gignit similitudinem suam, sic repraesentat generationem aeternam; secundum quod intentio animae eam oculo unit, sic repraesentat incarnationem Verbi*» (quoad aliam distinctionem generationum cfr. I. Sent. d. 13. dub. 8.). — De hac duplici generatione, sive potius in genere de duplici *actione* corporum loquitur pluries S. Thom., ut de Potent. q. 5. a. 8. in corp., ubi inter alia dicit: «*Haec autem est actio corporis, quae non est ad transmutationem materiae, sed ad quandam diffusionem similitudinis formae in medio, secundum similitudinem spiritualis intentionis, quae recipitur de re in sensu, vel intellectu; et hoc modo sol illuminat aërem, et color speciem suam multi-*

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*plicat in medio. Uterque autem modus actionis in istis inferioribus causatur ex corporibus caelestibus*». Idem S. I. q. 78. a. 3. plura dicit de duplici immutatione, quae est in corporibus, vel secundum *esse naturale*, vel secundum *esse spirituale* (immateriale). — Utriusque autem generationis mirabilis vis attribuenda est formis rerum, et eadem est reducenda originaliter ad rationes ideales in mente Dei (cfr. I. Sent. d. 38. q. 1, scholion, et S. Thom. S. I. q. 115. a. 2. ad 1.).

**II.** Quoad memoratam controversiam Aegid. R. (loc. cit. a. 2. ad 2.) dicit, quod «*lux habet esse reale, sed lumen habet esse intentionale*». Ex quo concludit, quod lumen et lux non sint eiusdem speciei. Etiam Scoto attribuitur opinio, quod lumen sit forma intentionalis, non naturalis; tamen (hic q. unica, n. 3.) non negat, lumen esse qualitatem naturalem in hoc sensu, quod realiter existat, sed vult, quod proprie et formaliter sit intentio, id est species impressa visibilis ipsius lucis (cfr. Comment. Lychet. ad hunc locum n. 9. seqq.). — Sententia S. Thomae (ut eam exponit Phil. a ss. Trinitate, Sum. philos. secund. secundae q. 34. a. 1.) haec est, quod lux «*est qualitas pure naturalis, quae definitur esse actus perspicui, ut perspicuum est, sive ut illustratum et illuminatum est*» (cfr. S. I, q. 67. a. 3.). In Comment. autem (hic q. unica, a. 3.) de opinione, quod lux sit tantum intentio, dicit primo: «*Et haec opinio valde probabilis est*»; deinde autem addit: «*Unde non potest esse, quod habeat esse intentionis tantum*». — S. Bonav. mediam quandam viam ingreditur, ut patet. — Ceterum si *lumen* cum recentioribus concipitur stricte, ut dicit motus undulatorios aetheris, tunc certe distinguendum est ab eo quod proprie *intentio* vocatur, ad quam isti motus se habent tantum in ratione causae materialis.

Auctores non citatos vide a. 2. q. 1, scholion.

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english_scholion:
**I.** Here it is treated of lumen as it is in the medium, not in the luminous body. S. Bonaventure again distinguishes this in two ways, namely insofar as it is an *active power*, not sensible, which has a manifold action upon this corporeal world and goes forth from the luminous body, to which it is consubstantial; and insofar as it is a visible phenomenon and an *accidental sensible quality*. On the nature of this quality the Scholastics disagree, since «*quality is distinguished into sensible quality and into the quality which is the species or intention of a sensible quality*» (Scotus, here q. unica, n. 3). It is controverted whether sensible lumen is an *intentional* and not *natural* quality, or a *natural* and not *intentional* one, or formally both natural and intentional. That this controversy may be better understood, we premise two things.

*1.* As to the *sense* of the term *intentio*, Scotus (II *Report.*, here q. unica, n. 4) says: «*The* name intentio *is equivocal: in one way it is said [to mean] an act of the will; secondly, a formal account in the thing, as the* intentio *of the thing from which* genus *is taken differs from the* intentio *from which* differentia *is taken; in a third mode it is said [to mean]* concept; *fourth, a* ratio of tending toward an object, *as a likeness is said to be the* ratio of tending *toward that whose [likeness] it is. And in this mode* lumen *is said [to be] the* intentio *or species of lux*».

*2.* The Scholastics commonly speak of two generations of forms which are verified by experience, namely *real* forms, which in generation are educed from the potency of matter, and *intentional* forms, which are not educed from the potency of matter. On the difference and likeness of each generation, Aegidius R. brings forward much (here q. 2, a. 2, and *dub. lat.*). — Of each generation S. Bonaventure speaks with marvellous subtlety in *Hexaëm.*, Sermo II, where he distinguishes twelve generations, of which four are by *diffusion*, four by *expression*, four by *propagation*. Among the generations by diffusion he puts in the first place the generation of *splendor from lux*; among the generations by expression, the generation of the *species from the object*, of which he says: «*And this is marvellous, how a species is generated, because not from the matter of the air, because, since it does not denote essence but* mode of being, *it suffices that it have an* originative *principle, a middle between the material principle and the effective principle. Hence God gave a power to every thing, that it might beget its likeness from natural fecundity. Hence accordingly as the object begets its likeness, it represents the eternal generation; accordingly as the intention of the soul unites it to the eye, it represents the incarnation of the Word*» (on the other distinction of generations cf. I *Sent.* d. 13, dub. 8). — Of this twofold generation, or rather in general of the twofold *action* of bodies, S. Thomas speaks many times, as in *De Potent.* q. 5, a. 8, in the body, where among other things he says: «*But this is an action of body which is not unto the transmutation of matter, but unto a certain diffusion of a likeness of form in the medium, according to the likeness of the spiritual intention which is received from the thing in sense or in the intellect; and in this way the sun illumines the air, and color multi-*

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*plies its species in the medium. Each mode of action in these lower things is caused by the celestial bodies*». The same [Thomas] *S.* I, q. 78, a. 3, says many things of the twofold change which is in bodies, either according to *natural being* or according to *spiritual* (immaterial) *being*. — The marvellous force of each generation is to be attributed to the forms of things, and the same is to be reduced originally to the ideal accounts in the mind of God (cf. I *Sent.* d. 38, q. 1, scholion, and S. Thom. *S.* I, q. 115, a. 2, ad 1).

**II.** As to the aforesaid controversy, Aegidius R. (loc. cit., a. 2, ad 2) says that «*lux has real being, but lumen has intentional being*». From which he concludes that lumen and lux are not of the same species. To Scotus also is attributed the opinion that lumen is an intentional and not a natural form; yet (here q. unica, n. 3) he does not deny that lumen is a natural quality in this sense, that it really exists, but he holds that properly and formally it is intention, i.e. an impressed visible species of lux itself (cf. *Comment. Lychet.* on this place, n. 9 and following). — The opinion of S. Thomas (as Philip of the Holy Trinity expounds it, *Sum. philos.*, *secund. secundae* q. 34, a. 1) is that lux «*is a purely natural quality, which is defined as the act of the perspicuous, insofar as it is perspicuous, or as it is illuminated and illumined*» (cf. *S.* I, q. 67, a. 3). But in [his] *Comment.* (here q. unica, a. 3), on the opinion that lux is only intention, he says first: «*And this opinion is very probable*»; then he adds: «*Hence it cannot be that it has only intentional being*». — S. Bonaventure enters upon a certain middle way, as is plain. — Furthermore, if *lumen* is conceived strictly with the moderns, as denoting undulatory motions of the aether, then certainly it is to be distinguished from what is properly called *intentio*, to which those motions stand only in the *ratio* of material cause.

For the authors not cited, see a. 2, q. 1, scholion.

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translators_notes:
- **Page span**: q2 opens at **top of p.327** with centred "QUAESTIO II." banner + italic rubric *Utrum lumen sit forma substantialis, an accidentalis*. Body videtur items 1–4 (*Fundamenta*) + CONTRA items 1–4 (*Ad oppositum*) + CONCLUSIO + Respondeo opener + Opinio 1 on p.327 L→R. Opinio 2 + Opinio 3 + *Improbatur* + *Iudicium de praedictis* + *Lumen dicit virtutem activam* + *2. qualitatem sensibilem* + *Notandum* on p.328 L→R. Body close + *Conclusio de membris* + *Ex his patent rationes* + *Ad fundamenta 1–4* + *Ad opposita* + *De accidente naturali* + *De lumine ut accidente* + close of body + SCHOLION items I + II opener + part of item I on p.329 L→R. SCHOLION items I close + item II + closing line *Auctores non citatos vide a. 2. q. 1, scholion.* on **p.330 L-0 / R-0** (the d13-a3-q2 portion of p.330 ends mid-page; "DUBIA CIRCA LITTERAM MAGISTRI" banner opens d13-dubia below it).
- **Apparatus count**: 23 entries — 10 on p.327 + 9 on p.328 + 4 on p.329 — renumbered sequentially [^1]–[^23] in body-order of appearance (which matches printed-footer order on each page). No p.330 footnotes belong to this chunk; the p.330 footer is shared with d13-dubia (which carries its own apparatus from p.330+ printed footer).
- **Scholion**: two enumerated items (I, II) — item I distinguishes *virtus activa* vs *accidentalis qualitas sensibilis* and lays out the Scholastic controversy on whether sensible lumen is intentional / natural / formally both, with two premised distinctions (1. sense of *intentio* per Scotus; 2. real vs intentional generations of forms per Aegidius R. + S. Bonaventure's *Hexaëm.* Serm. II twelve-fold scheme + S. Thomas *De Potent.* q. 5 a. 8). Item II surveys the controversy proper: Aegidius R. (lux real / lumen intentional), Scotus (attributed intentionalist but qualifies in q. unica n. 3), S. Thomas (lux as pure natural quality per Phil. a ss. Trinitate; *Comment.* nuances), S. Bonav. as middle way, plus the modern (post-1800s) distinction of *lumen* as undulatory aether-motion vs *intentio* in the *ratio* of material cause. Closes with the cross-reference "*Auctores non citatos vide a. 2. q. 1, scholion.*" which points the reader back to d13-a2-q1's scholion for the unnamed authors.
- **Boundary integrity (per CLAUDE.md polish-cadence pass 3)**: backward boundary with `d13-a3-q1` at p.327 top is clean — q1 scholion ends on p.326 R bottom, and the centred "QUAESTIO II." banner opens at the very top of p.327 below the "DIST. XIII. ART. III. QUAEST. II." running head. Forward boundary at p.330 R-0 mid is clean — the q2 scholion's final line "*Auctores non citatos vide a. 2. q. 1, scholion.*" sits immediately above the centred "DUBIA CIRCA LITTERAM MAGISTRI." banner that opens d13-dubia.
- **OCR-vs-PDF reconciliation**: the IA djvu OCR for these three columns cascade-merged left and right column lines (especially Respondeo through Notandum on p.328); reconstruction proceeded column-by-column per the Vol II Override recipe (read L-0 → L-1 → L-2 → R-0 → R-1 → R-2, body bands first, footer bands second). The OCR's "h. Item, nullum accidens manet immobile…" at the head of CONTRA item 4 is a digit-mangle of "4." confirmed by direct p.327 R-0 read.
- **Frontmatter line-range**: `line_start: 23122, line_end: 23351` matches the semantic range (QUAESTIO II opener "*Utrum lumen sit forma substantialis…*" → end of scholion "*Auctores non citatos vide a. 2. q. 1, scholion.*"). The auto-chunker boundary is correct; the residual scholion tail on p.330 sits at lines 23330–23351.
- **No `[?]` flags raised.** Body and apparatus reconciled against p.327 L-0/L-1/L-2/R-0/R-1/R-2, p.328 L-0/L-1/L-2/R-0/R-1/R-2, p.329 L-0/L-1/L-2/R-0/R-1/R-2, p.330 L-0/R-0. Marginal labels (*Fundamenta.*, *Ad oppositum.*, *Opinio 1.*, *Opinio 2.*, *Opinio 3.*, *Improbatur.*, *Iudicium de praedictis.*, *Lumen dicit 1. virtutem activam.*, *2. qualitatem sensibilem.*, *Notandum.*, *Conclusio de membris.*, *Ad fundamenta.*, *Ad opposita.*, *De accidente naturali.*, *De lumine ut accidente.*) preserved inline per Vol II convention, not promoted to headings.