No. There was not only one day because God created all things together so far as regards their substance in some measure formless, but He did not create all things together, so far as regards that formation of things which lies in distinction and adornment. (Hence the word "creation" is significant in (Sirach 18:1): "He that liveth for ever, created all things together.")
Non fuit unus dies tantum quod Deus creavit omnia simul, quantum ad rerum substantiam quodammodo informem. Sed quantum ad formationem quae facta est per distinctionem et ornatum, non simul. (Unde signanter utitur verbo "creationis": Eccli. XVIII, dicitur, "qui vivit in aeternum, creavit omnia simul.")
All things were not distinguished and adorned together, not from a want of power on God's part, as requiring time in which to work, but that due order might be observed in the instituting of the world. Hence it was fitting that different days should be assigned to the different states of the world, as each succeeding work added to the world a fresh state of perfection.
Non est ex impotentia Dei, quasi indigentis tempore ad operandum, quod omnia non sunt simul distincta et ornata, sed ut ordo servaretur in rerum institutione. Et ideo oportuit ut diversis statibus mundi diversi dies deservirent. Semper autem per sequens opus novus perfectionis status mundo est additus.
According to Augustine, the order of days refers to the natural order of the works attributed to the days.
Secundum Augustinum, ille ordo dierum referendus est ad naturalem ordinem operum quae diebus attribuuntur.
On this question Augustine differs from other expositors. His opinion is that all the days that are called seven, are one day represented in a sevenfold aspect (Gen. ad lit. iv, 22; De Civ. Dei xi, 9; Ad Orosium xxvi); while others consider there were seven distinct days, not one only. Now, these two opinions, taken as explaining the literal text of Genesis, are certainly widely different.
In hac quaestione Augustinus ab aliis expositoribus dissentit. Augustinus enim vult, et super Gen. ad Litt., et XI de Civ. Dei, et ad Orosium, quod omnes qui dicuntur septem dies, sunt unus dies septempliciter rebus praesentatus. Alii vero expositores sentiunt quod fuerunt septem dies diversi, et non unus tantum. Hae autem duae opiniones, si referantur ad expositionem litterae Genesis, magnam diversitatem habent.
For Augustine understands by the word "day," the knowledge in the mind of the angels, and hence, according to him, the first day denotes their knowledge of the first of the Divine works, the second day their knowledge of the second work, and similarly with the rest. Thus, then, each work is said to have been wrought in some one of these days, inasmuch as God wrought in some one of these days, inasmuch as God wrought nothing in the universe without impressing the knowledge thereof on the angelic mind; which can know many things at the same time, especially in the Word, in Whom all angelic knowledge is perfected and terminated.
Nam secundum Augustinum, per "diem" intelligitur cognitio mentis angelicae; ut sic primus dies sit cognito primi divini operis, secundus dies cognitio secundi operis, et sic de aliis. Et dicitur unumquodque opus esse factum in aliqua die, quia nihil Deus produxit in rerum natura, quod non impresserit menti angelicae. Quae quidem multa simul potest cognoscere, praecipue in verbo, in quo omnis Angelorum cognitio perficitur et terminatur.
So the distinction of days denotes the natural order of the things known, and not a succession in the knowledge acquired, or in the things produced.
Et sic distinguitur dies secundum naturalem ordinem rerum cognitarum, non secundum successionem cognitionis, aut secundum successionem productionis rerum.
Moreover, angelic knowledge is appropriately called "day," since light, the cause of day, is to be found in spiritual things, as Augustine observes (Gen. ad lit. iv, 28). In the opinion of the others, however, the days signify a succession both in time, and in the things produced.
Cognitio autem angelica proprie et vere "dies" nominari potest, cum lux, quae est causa diei, proprie in spiritualibus, secundum Augustinum, inveniatur. Secundum vero alios, per istos dies et successio dierum temporalium ostenditur, et successio productionis rerum.
If, however, these two explanations are looked at as referring to the mode of production, they will be found not greatly to differ, if the diversity of opinion existing on two points, as already shown (Q67, A1; Q69, A1), between Augustine and other writers is taken into account.
Sed si istae duae opiniones referantur ad modum productionis rerum, non invenitur magna differentia. Et hoc propter duo in quibus, exponendo, diversificatur Augustinus ab aliis, ut ex supra dictis patet.
First, because Augustine takes the earth and the water as first created, to signify matter totally without form; but the making of the firmament, the gathering of the waters, and the appearing of dry land, to denote the impression of forms upon corporeal matter.
Primo quidem, quia Augustinus per terram et aquam prius creatam, intelligit materiam corporalem totaliter informem; per factionem autem firmamenti, et congregationem aquarum, et apparitionem aridae, intelligit impressionem formarum in materiam corporalem.
But other holy writers take the earth and the water, as first created, to signify the elements of the universe themselves existing under the proper forms, and the works that follow to mean some sort of distinction in bodies previously existing, as also has been shown (Q67, A1; Q67, A4; Q69, A1).
Alii vero sancti per terram et aquam primo creatas, intelligunt ipsa elementa mundi, sub propriis formis existentia, per sequentia autem opera, aliquam distinctionem in corporibus prius existentibus, ut supra dictum est.
Secondly, some writers hold that plants and animals were produced actually in the work of the six days; Augustine, that they were produced potentially.
Secundo autem differunt quantum ad productionem plantarum et animalium, quae alii ponunt in opere sex dierum esse producta in actu; Augustinus vero potentialiter tantum.
On the day on which God created the heaven and the earth, He created also every plant of the field, not, indeed, actually, but "before it sprung up in the earth," that is, potentially. And this work Augustine ascribes to the third day, but other writers to the first instituting of the world.
In die in quo creavit Deus caelum et terram, creavit etiam omne virgultum agri, non in actu, sed "antequam oriretur super terram," idest potentialiter. Quod Augustinus adscribit tertiae diei, alii vero primae rerum institutioni.
Now the opinion of Augustine, that the works of the six days were simultaneous, is consistent with either view of the mode of production. For the other writers agree with him that in the first production of things matter existed under the substantial form of the elements, and agree with him also that in the first instituting of the world animals and plants did not exist actually.
In hoc ergo quod Augustinus ponit opera sex dierum esse simul facta, sequitur idem modus productionis rerum. Nam secundum utrosque, in prima rerum productione materia erat sub formis substantialibus elementorum, et secundum utrosque, in prima rerum institutione non fuerunt animalia et plantae in actu.
There remains, however, a difference as to four points; since, according to the latter, there was a time, after the production of creatures, in which
(1) light did not exist,
(2) the firmament had not been formed,
(3) and the earth was still covered by the waters,
(4) nor had the heavenly bodies been formed,
which is the fourth difference; which are not consistent with Augustine's explanation. "Therefore, in order not to do prejudice to either of these opinions, we must reply to the arguments for both sides."
Sed remanet differentia quantum ad quatuor. Quia secundum alios sanctos, post primam productionem creaturae, fuit aliquod tempus
in quo non erat lux;
item in quo non erat firmamentum formatum;
item in quo non erat terra discooperta aquis;
et in quo non erant formata caeli luminaria,
quod est quartum. Quae non oportet ponere secundum expositionem Augustini. Ut igitur neutri sententiae praeiudicetur, utriusque rationibus respondendum est.
On the seventh day God ceased from making new things, but not from providing for their increase, and to this latter work it belongs that the first day is succeeded by other days.
In die septimo cessavit Deus a novis operibus condendis, non autem a propagandis quibusdam ex aliis, ad quam propagationem pertinet quod post primum diem alii succedunt.