1 Objection 1: It would seem that light is used in its proper sense in spiritual things. For Augustine says Gen. ad lit. iv, 28) that in spiritual things light is better and surer: and that Christ is not called Light in the same sense as He is called the Stone; the former is to be taken literally, and the latter metaphorically.
1 Ad primum sic proceditur. Videtur quod lux proprie in spiritualibus dicatur. Dicit enim Augustinus, IV super Gen. ad Litt., quod in spiritualibus melior et certior lux est, et quod Christus non sic dicitur lux quo modo lapis, sed illud proprie, hoc figurative.
2 Objection 2: Further, Dionysius Div. Nom. iv) includes Light among the intellectual names of God. But such names are used in their proper sense in spiritual things. Therefore light is used in its proper sense in spiritual matters.
2 Praeterea, Dionysius, IV cap. de Div. Nom., ponit lumen inter nomina intelligibilia Dei. Nomina autem intelligibilia proprie dicuntur in spiritualibus. Ergo lux proprie dicitur in spiritualibus.
3 Objection 3: Further, the Apostle says Eph. 5, 13): All that is made manifest is light. But to be made manifest belongs more properly to spiritual things than to corporeal. Therefore also does light.
3 Praeterea, apostolus dicit, ad Ephes. V, omne quod manifestatur, lumen est. Sed manifestatio magis proprie est in spiritualibus quam in corporalibus. Ergo et lux.
4 On the contrary, Ambrose says De Fide ii) that Splendor is among those things which are said of God metaphorically.
4 Sed contra est quod Ambrosius, in libro de fide, ponit splendorem inter ea quae de Deo metaphorice dicuntur.
5 I answer that, Any word may be used in two ways, that is to say, either in its original application or in its more extended meaning. This is clearly shown in the word sight, originally applied to the act of the sense, and then, as sight is the noblest and most trustworthy of the senses, extended in common speech to all knowledge obtained through the other senses. Thus we say, Seeing how it tastes, or smells, or burns. Further, sight is applied to knowledge obtained through the intellect, as in those words: Blessed are the clean of heart, for they shall see God Mt. 5, 8). And thus it is with the word light. In its primary meaning it signifies that which makes manifest to the sense of sight; afterwards it was extended to that which makes manifest to cognition of any kind. If, then, the word is taken in its strict and primary meaning, it is to be understood metaphorically when applied to spiritual things, as Ambrose says De Fide ii). But if taken in its common and extended use, as applied to manifestation of every kind, it may properly be applied to spiritual things. The answer to the objections will sufficiently appear from what has been said.
5 Respondeo dicendum quod de aliquo nomine dupliciter convenit loqui, uno modo, secundum primam eius impositionem; alio modo, secundum usum nominis. Sicut patet in nomine visionis, quod primo impositum est ad significandum actum sensus visus; sed propter dignitatem et certitudinem huius sensus, extensum est hoc nomen, secundum usum loquentium, ad omnem cognitionem aliorum sensuum dicimus enim, vide quomodo sapit, vel quomodo redolet, vel quomodo est calidum); et ulterius etiam ad cognitionem intellectus, secundum illud Matth. V, beati mundo corde, quoniam ipsi Deum videbunt. Et similiter dicendum est de nomine lucis. Nam primo quidem est institutum ad significandum id quod facit manifestationem in sensu visus, postmodum autem extensum est ad significandum omne illud quod facit manifestationem secundum quamcumque cognitionem. Si ergo accipiatur nomen luminis secundum suam primam impositionem, metaphorice in spiritualibus dicitur, ut Ambrosius dicit. Si autem accipiatur secundum quod est in usu loquentium ad omnem manifestationem extensum, sic proprie in spiritualibus dicitur. Et per hoc patet responsio ad obiecta.