Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the firmament does not divide waters from waters. For bodies that are of one and the same species have naturally one and the same place. But the Philosopher says (Topic. i, 6): "All water is the same species." Water therefore cannot be distinct from water by place.

Objection 2: Further, should it be said that the waters above the firmament differ in species from those under the firmament, it may be argued, on the contrary, that things distinct in species need nothing else to distinguish them. If then, these waters differ in species, it is not the firmament that distinguishes them.

Objection 3: Further, it would appear that what distinguishes waters from waters must be something which is in contact with them on either side, as a wall standing in the midst of a river. But it is evident that the waters below do not reach up to the firmament. Therefore the firmament does not divide the waters from the waters.

On the contrary, It is written (Gn. 1:6): "Let there be a firmament made amidst the waters; and let it divide the waters from the waters."

I answer that, The text of Genesis, considered superficially, might lead to the adoption of a theory similar to that held by certain philosophers of antiquity, who taught that water was a body infinite in dimension, and the primary element of all bodies. Thus in the words, "Darkness was upon the face of the deep," the word "deep" might be taken to mean the infinite mass of water, understood as the principle of all other bodies. These philosophers also taught that not all corporeal things are confined beneath the heaven perceived by our senses, but that a body of water, infinite in extent, exists above that heaven. On this view the firmament of heaven might be said to divide the waters without from those within---that is to say, from all bodies under the heaven, since they took water to be the principle of them all.

As, however, this theory can be shown to be false by solid reasons, it cannot be held to be the sense of Holy Scripture. It should rather be considered that Moses was speaking to ignorant people, and that out of condescension to their weakness he put before them only such things as are apparent to sense. Now even the most uneducated can perceive by their senses that earth and water are corporeal, whereas it is not evident to all that air also is corporeal, for there have even been philosophers who said that air is nothing, and called a space filled with air a vacuum.

Moses, then, while he expressly mentions water and earth, makes no express mention of air by name, to avoid setting before ignorant persons something beyond their knowledge. In order, however, to express the truth to those capable of understanding it, he implies in the words: "Darkness was upon the face of the deep," the existence of air as attendant, so to say, upon the water. For it may be understood from these words that over the face of the water a transparent body was extended, the subject of light and darkness, which, in fact, is the air.

Whether, then, we understand by the firmament the starry heaven, or the cloudy region of the air, it is true to say that it divides the waters from the waters, according as we take water to denote formless matter, or any kind of transparent body, as fittingly designated under the name of waters. For the starry heaven divides the lower transparent bodies from the higher, and the cloudy region divides that higher part of the air, where the rain and similar things are generated, from the lower part, which is connected with the water and included under that name.

Reply to Objection 1: If by the firmament is understood the starry heaven, the waters above are not of the same species as those beneath. But if by the firmament is understood the cloudy region of the air, both these waters are of the same species, and two places are assigned to them, though not for the same purpose, the higher being the place of their begetting, the lower, the place of their repose.

Reply to Objection 2: If the waters are held to differ in species, the firmament cannot be said to divide the waters, as the cause of their destruction, but only as the boundary of each.

Reply to Objection 3: On account of the air and other similar bodies being invisible, Moses includes all such bodies under the name of water, and thus it is evident that waters are found on each side of the firmament, whatever be the sense in which the word is used.

Articulus 3

Argumentum 1

Ad tertium sic proceditur. Videtur quod firmamentum non dividat aquas ab aquis. Unius enim corporis secundum speciem, est unus locus naturalis. Sed omnis aqua omni aquae est eadem specie, ut dicit philosophus.

Non ergo aquae ab aquis sunt distinguendae secundum locum.

Argumentum 2

Si dicatur quod aquae illae quae sunt supra firmamentum, sunt alterius speciei ab aquis quae sunt sub firmamento, contra, ea quae sunt secundum speciem diversa, non indigent aliquo alio distinguente. Si ergo aquae superiores et inferiores specie differunt, firmamentum eas ab invicem non distinguit.

Argumentum 3

Praeterea, illud videtur aquas ab aquis distinguere, quod ex utraque parte ab aquis contingitur; sicut si aliquis paries fabricetur in medio fluminis. Manifestum est autem quod aquae inferiores non pertingunt usque ad firmamentum.

Ergo non dividit firmamentum aquas ab aquis.

Sed Contra

Sed contra est quod dicitur Gen. I, fiat firmamentum in medio aquarum, et dividat aquas ab aquis.

Corpus

Respondeo dicendum quod aliquis, considerando superficie tenus litteram Genesis, posset talem imaginationem concipere, secundum quorundam antiquorum philosophorum positionem.

Posuerunt enim quidam aquam esse quoddam infinitum corpus, et omnium aliorum corporum principium. Quam quidem immensitatem aquarum accipere posset in nomine abyssi, cum dicitur quod tenebrae erant super faciem abyssi. Ponebant etiam quod istud caelum sensibile quod videmus, non continet infra se omnia corporalia; sed est infinitum aquarum corpus supra caelum. Et ita posset aliquis dicere quod firmamentum caeli dividit aquas exteriores ab aquis interioribus, idest ab omnibus corporibus quae infra caelum continentur, quorum principium aquam ponebant.

Sed quia ista positio per veras rationes falsa deprehenditur, non est dicendum hunc esse intellectum Scripturae. Sed considerandum est quod Moyses rudi populo loquebatur, quorum imbecillitati condescendens, illa solum eis proposuit, quae manifeste sensui apparent. Omnes autem, quantumcumque rudes, terram et aquam esse corpora sensu deprehendunt. Aer autem non percipitur ab omnibus esse corpus, intantum quod etiam quidam philosophi aerem dixerunt nihil esse, plenum aere vacuum nominantes.

Et ideo Moyses de aqua et terra mentionem facit expressam, aerem autem non expresse nominat, ne rudibus quoddam ignotum proponeret. Ut tamen capacibus veritatem exprimeret, dat locum intelligendi aerem, significans ipsum quasi aquae annexum, cum dicit quod tenebrae erant super faciem abyssi; per quod datur intelligi super faciem aquae esse aliquod corpus diaphanum quod est subiectum lucis et tenebrarum. Sic igitur sive per firmamentum intelligamus caelum in quo sunt sidera, sive spatium aeris nubilosum, convenienter dicitur quod firmamentum dividit aquas ab aquis, secundum quod per aquam materia informis significatur; vel secundum quod omnia corpora diaphana sub nomine aquarum intelliguntur. Nam caelum sidereum distinguit corpora inferiora diaphana a superioribus. Aer vero nubilosus distinguit superiorem aeris partem, in qua generantur pluviae et huiusmodi impressiones, ab inferiori parte aeris, quae aquae connectitur, et sub nomine aquarum intelligitur.

Ad 1

Ad primum ergo dicendum quod, si per firmamentum intelligatur caelum sidereum, aquae superiores non sunt eiusdem speciei cum inferioribus. Si autem per firmamentum intelligatur nubilosus aer, tunc utraeque aquae sunt eiusdem speciei. Et deputantur tunc duo loca aquis non eadem ratione; sed locus superior est locus generationis aquarum, locus autem inferior est locus quietis earum.

Ad 2

Ad secundum dicendum quod, si accipiantur aquae diversae secundum speciem, firmamentum dicitur dividere aquas ab aquis, non sicut causa faciens divisionem; sed sicut terminus utrarumque aquarum.

Ad 3

Ad tertium dicendum quod Moyses, propter invisibilitatem aeris et similium corporum, omnia huiusmodi corpora sub aquae nomine comprehendit. Et sic manifestum est quod ex utraque parte firmamenti, qualitercumque accepti, sunt aquae.