Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that there are not waters above the firmament. For water is heavy by nature, and heavy things tend naturally downwards, not upwards. Therefore there are not waters above the firmament.

Objection 2: Further, water is fluid by nature, and fluids cannot rest on a sphere, as experience shows. Therefore, since the firmament is a sphere, there cannot be water above it.

Objection 3: Further, water is an element, and appointed to the generation of composite bodies, according to the relation in which imperfect things stand towards perfect. But bodies of composite nature have their place upon the earth, and not above the firmament, so that water would be useless there. But none of God's works are useless. Therefore there are not waters above the firmament.

On the contrary, It is written (Gn. 1:7): "(God) divided the waters that were under the firmament, from those that were above the firmament."

I answer with Augustine (Gen. ad lit. ii, 5) that, "These words of Scripture have more authority than the most exalted human intellect. Hence, whatever these waters are, and whatever their mode of existence, we cannot for a moment doubt that they are there." As to the nature of these waters, all are not agreed. Origen says (Hom. i in Gen.) that the waters that are above the firmament are "spiritual substances." Wherefore it is written (Ps. 148:4): "Let the waters that are above the heavens praise the name of the Lord," and (Dn. 3:60): "Ye waters that are above the heavens, bless the Lord."To this Basil answers (Hom. iii in Hexaem.) that these words do not mean that these waters are rational creatures, but that "the thoughtful contemplation of them by those who understand fulfils the glory of the Creator." Hence in the same context, fire, hail, and other like creatures, are invoked in the same way, though no one would attribute reason to these.

We must hold, then, these waters to be material, but their exact nature will be differently defined according as opinions on the firmament differ. For if by the firmament we understand the starry heaven, and as being of the nature of the four elements, for the same reason it may be believed that the waters above the heaven are of the same nature as the elemental waters. But if by the firmament we understand the starry heaven, not, however, as being of the nature of the four elements then the waters above the firmament will not be of the same nature as the elemental waters, but just as, according to Strabus, one heaven is called empyrean, that is, fiery, solely on account of its splendor: so this other heaven will be called aqueous solely on account of its transparence; and this heaven is above the starry heaven. Again, if the firmament is held to be of other nature than the elements, it may still be said to divide the waters, if we understand by water not the element but formless matter. Augustine, in fact, says (Super Gen. cont. Manich. i, 5,7) that whatever divides bodies from bodies can be said to divide waters from waters.

If, however, we understand by the firmament that part of the air in which the clouds are collected, then the waters above the firmament must rather be the vapors resolved from the waters which are raised above a part of the atmosphere, and from which the rain falls. But to say, as some writers alluded to by Augustine (Gen. ad lit. ii, 4), that waters resolved into vapor may be lifted above the starry heaven, is a mere absurdity. The solid nature of the firmament, the intervening region of fire, wherein all vapor must be consumed, the tendency in light and rarefied bodies to drift to one spot beneath the vault of the moon, as well as the fact that vapors are perceived not to rise even to the tops of the higher mountains, all to go to show the impossibility of this. Nor is it less absurd to say, in support of this opinion, that bodies may be rarefied infinitely, since natural bodies cannot be infinitely rarefied or divided, but up to a certain point only.

Reply to Objection 1: Some have attempted to solve this difficulty by supposing that in spite of the natural gravity of water, it is kept in its place above the firmament by the Divine power. Augustine (Gen. ad lit. ii, 1), however will not admit this solution, but says "It is our business here to inquire how God has constituted the natures of His creatures, not how far it may have pleased Him to work on them by way of miracle." We leave this view, then, and answer that according to the last two opinions on the firmament and the waters the solution appears from what has been said. According to the first opinion, an order of the elements must be supposed different from that given by Aristotle, that is to say, that the waters surrounding the earth are of a dense consistency, and those around the firmament of a rarer consistency, in proportion to the respective density of the earth and of the heaven.

Or by the water, as stated, we may understand the matter of bodies to be signified.

Reply to Objection 2: The solution is clear from what has been said, according to the last two opinions. But according to the first opinion, Basil gives two replies (Hom. iii in Hexaem.). He answers first, that a body seen as concave beneath need not necessarily be rounded, or convex, above. Secondly, that the waters above the firmament are not fluid, but exist outside it in a solid state, as a mass of ice, and that this is the crystalline heaven of some writers.

Reply to Objection 3: According to the third opinion given, the waters above the firmament have been raised in the form of vapors, and serve to give rain to the earth. But according to the second opinion, they are above the heaven that is wholly transparent and starless. This, according to some, is the primary mobile, the cause of the daily revolution of the entire heaven, whereby the continuance of generation is secured. In the same way the starry heaven, by the zodiacal movement, is the cause whereby different bodies are generated or corrupted, through the rising and setting of the stars, and their various influences. But according to the first opinion these waters are set there to temper the heat of the celestial bodies, as Basil supposes (Hom. iii in Hexaem.). And Augustine says (Gen. ad lit. ii, 5) that some have considered this to be proved by the extreme cold of Saturn owing to its nearness to the waters that are above the firmament.

Articulus 2

Argumentum 1

Ad secundum sic proceditur. Videtur quod aquae non sunt supra firmamentum. Aqua enim est naturaliter gravis. Locus autem proprius gravis non est esse sursum, sed solum deorsum.

Ergo aquae non sunt supra firmamentum.

Argumentum 2

Praeterea, naturaliter aqua est fluida. Sed quod est fluidum, non potest consistere super corpus rotundum, ut experimento patet.

Ergo, cum firmamentum sit corpus rotundum, aqua non potest esse supra firmamentum.

Argumentum 3

Praeterea, aqua, cum sit elementum, ordinatur ad generationem corporis mixti; sicut imperfectum ordinatur ad perfectum.

Sed supra firmamentum non est locus mixtionis, sed supra terram.

Ergo frustra aqua esset supra firmamentum. Nihil autem in operibus dei est frustra. Ergo aquae non sunt supra firmamentum.

Sed Contra

Sed contra est quod dicitur Gen. I, quod divisit aquas quae erant supra firmamentum, ab his quae erant sub firmamento.

Corpus

Respondeo dicendum quod, sicut dicit Augustinus, II super Gen. Ad litt., maior est Scripturae huius auctoritas quam omnis humani ingenii capacitas. Unde quomodo et quales aquae ibi sint, eas tamen ibi esse, minime dubitamus.

Quales autem sint illae aquae, non eodem modo ab omnibus assignatur.

Origenes enim dicit quod aquae illae quae super caelos sunt, sunt spirituales substantiae, unde in Psalmo CXLVIII, dicitur, aquae quae super caelos sunt, laudent nomen domini; et Dan. III, benedicite, aquae omnes quae super caelos sunt, domino.

Sed ad hoc respondet basilius, in III hexaem., quod hoc non dicitur eo quod aquae sint rationales creaturae; sed quia consideratio earum, prudenter a sensum habentibus contemplata, glorificationem perficit creatoris.

Unde ibidem dicitur idem de igne et grandine et huiusmodi, de quibus constat quod non sunt rationales creaturae. Dicendum est ergo quod sunt aquae corporales. Sed quales aquae sint, oportet diversimode definire, secundum diversam de firmamento sententiam.

Si enim per firmamentum intelligitur caelum sidereum quod ponitur esse de natura quatuor elementorum, pari ratione et aquae quae super caelos sunt, eiusdem naturae poterunt credi cum elementaribus aquis.

Si autem per firmamentum intelligatur caelum sidereum quod non sit de natura quatuor elementorum, tunc et aquae illae quae sunt supra firmamentum, non erunt de natura elementarium aquarum, sed sicut, secundum strabum, dicitur caelum empyreum, idest igneum, propter solum splendorem; ita dicetur aliud caelum aqueum propter solam diaphaneitatem, quod est supra caelum sidereum. Posito etiam quod firmamentum sit alterius naturae praeter quatuor elementa, adhuc potest dici quod aquas dividit, si per aquam non elementum aquae, sed materiam informem corporum intelligamus, ut Augustinus dicit, super Gen. Contra manich., quia secundum hoc, quidquid est inter corpora, dividit aquas ab aquis.

Si autem per firmamentum intelligatur pars aeris in qua nubes condensantur, sic aquae quae supra firmamentum sunt, sunt aquae quae, vaporabiliter resolutae, supra aliquam partem aeris elevantur ex quibus pluviae generantur.

Dicere enim quod aquae vaporabiliter resolutae eleventur supra caelum sidereum, ut quidam dixerunt, quorum opinionem Augustinus tangit in II super Gen. Ad litt.

Est omnino impossibile. Tum propter soliditatem caeli. Tum propter regionem ignis mediam, quae huiusmodi vapores consumeret. Tum quia locus quo feruntur levia et rara, est infra concavum orbis lunae.

Tum etiam quia sensibiliter apparet vapores non elevari usque ad cacumina quorundam montium.

Quod etiam dicunt de rarefactione corporis in infinitum, propter hoc quod corpus est in infinitum divisibile, vanum est. Non enim corpus naturale in infinitum dividitur aut rarefit, sed usque ad certum terminum.

Ad 1

Ad primum ergo dicendum quod quibusdam videtur ratio illa solvenda per hoc, quod aquae, quamvis sint naturaliter graves, virtute tamen divina super caelos continentur. Sed hanc solutionem Augustinus excludit, II Lib. Super Gen. Ad litt., dicens quod nunc quemadmodum deus instituit naturas rerum convenit quaerere; non quid in eis ad miraculum suae potentiae velit operari.

Unde aliter dicendum est quod, secundum duas ultimas opiniones de aquis et firmamento, patet solutio ex praemissis. Secundum autem primam opinionem, oportet ponere alium ordinem in elementis quam Aristoteles ponat; ut quaedam aquae spissae sint circa terram, quaedam vero tenues circa caelum; ut sic se habeant illae ad caelum, sicut istae ad terram. Vel quod per aquam intelligatur materia corporum, ut dictum est.

Ad 2

Ad secundum etiam patet solutio ex praemissis, secundum duas ultimas opiniones. Secundum vero primam, respondet basilius dupliciter.

Uno modo, quia non est necessarium ut omne quod in concavo apparet rotundum, sit etiam supra rotundum secundum convexum. Secundo, quia aquae quae sunt supra caelos, non sunt fluidae; sed quasi glaciali soliditate circa caelum firmatae.

Unde et a quibusdam dicuntur caelum crystallinum.

Ad 3

Ad tertium dicendum quod, secundum tertiam opinionem, aquae sunt supra firmamentum vaporabiliter elevatae propter utilitatem pluviarum. Secundum vero secundam opinionem, aquae sunt supra firmamentum, idest caelum totum diaphanum absque stellis.

Quod quidam ponunt primum mobile, quod revolvit totum caelum motu diurno, ut operetur per motum diurnum continuitatem generationis, sicut caelum in quo sunt sidera, per motum qui est secundum zodiacum, operatur diversitatem generationis et corruptionis, per accessum et recessum, et per diversas virtutes stellarum.

Secundum vero primam opinionem, aquae sunt ibi, ut basilius dicit, ad contemperandum calorem caelestium corporum.

Cuius signum acceperunt aliqui, ut Augustinus dicit, quod stella Saturni, propter vicinitatem aquarum superiorum, est frigidissima.