Thomas Aquinas, Summa Theologiae

Objection 1: It seems that aeviternity is the same as time. For Augustine says (Gen. ad lit. viii, 20,22,23), that "God moves the spiritual through time." But aeviternity is said to be the measure of spiritual substances. Therefore time is the same as aeviternity.

Objection 2: Further, it is essential to time to have "before" and "after"; but it is essential to eternity to be simultaneously whole, as was shown above in the first article. Now aeviternity is not eternity; for it is written (Ecclus. 1:1) that eternal "Wisdom is before age." Therefore it is not simultaneously whole but has "before" and "after"; and thus it is the same as time.

Objection 3: Further, if there is no "before" and "after" in aeviternity, it follows that in aeviternal things there is no difference between being, having been, or going to be. Since then it is impossible for aeviternal things not to have been, it follows that it is impossible for them not to be in the future; which is false, since God can reduce them to nothing.

Objection 4: Further, since the duration of aeviternal things is infinite as to subsequent duration, if aeviternity is simultaneously whole, it follows that some creature is actually infinite; which is impossible. Therefore aeviternity does not differ from time.

On the contrary, Boethius says (De Consol. iii) "Who commandest time to be separate from aeviternity."

I answer that, Aeviternity differs from time, and from eternity, as the mean between them both. This difference is explained by some to consist in the fact that eternity has neither beginning nor end, aeviternity, a beginning but no end, and time both beginning and end. This difference, however, is but an accidental one, as was shown above, in the preceding article; because even if aeviternal things had always been, and would always be, as some think, and even if they might sometimes fail to be, which is possible to God to allow; even granted this, aeviternity would still be distinguished from eternity, and from time.

Others assign the difference between these three to consist in the fact that eternity has no "before" and "after"; but that time has both, together with innovation and veteration; and that aeviternity has "before" and "after" without innovation and veteration. This theory, however, involves a contradiction; which manifestly appears if innovation and veteration be referred to the measure itself. For since "before" and "after" of duration cannot exist together, if aeviternity has "before" and "after," it must follow that with the receding of the first part of aeviternity, the after part of aeviternity must newly appear; and thus innovation would occur in aeviternity itself, as it does in time. And if they be referred to the things measured, even then an incongruity would follow. For a thing which exists in time grows old with time, because it has a changeable existence, and from the changeableness of a thing measured, there follows "before" and "after" in the measure, as is clear from Phys. iv. Therefore the fact that an aeviternal thing is neither inveterate, nor subject to innovation, comes from its changelessness; and consequently its measure does not contain "before" and "after." We say then that since eternity is the measure of a permanent being, in so far as anything recedes from permanence of being, it recedes from eternity. Now some things recede from permanence of being, so that their being is subject to change, or consists in change; and these things are measured by time, as are all movements, and also the being of all things corruptible. But others recede less from permanence of being, forasmuch as their being neither consists in change, nor is the subject of change; nevertheless they have change annexed to them either actually or potentially. This appears in the heavenly bodies, the substantial being of which is unchangeable; and yet with unchangeable being they have changeableness of place. The same applies to the angels, who have an unchangeable being as regards their nature with changeableness as regards choice; moreover they have changeableness of intelligence, of affections and of places in their own degree. Therefore these are measured by aeviternity which is a mean between eternity and time. But the being that is measured by eternity is not changeable, nor is it annexed to change. In this way time has "before" and "after"; aeviternity in itself has no "before" and "after," which can, however, be annexed to it; while eternity has neither "before" nor "after," nor is it compatible with such at all.

Reply to Objection 1: Spiritual creatures as regards successive affections and intelligences are measured by time. Hence also Augustine says (Gen. ad lit. viii, 20,22,23) that to be moved through time, is to be moved by affections. But as regards their nature they are measured by aeviternity; whereas as regards the vision of glory, they have a share of eternity.

Reply to Objection 2: Aeviternity is simultaneously whole; yet it is not eternity, because "before" and "after" are compatible with it.

Reply to Objection 3: In the very being of an angel considered absolutely, there is no difference of past and future, but only as regards accidental change. Now to say that an angel was, or is, or will be, is to be taken in a different sense according to the acceptation of our intellect, which apprehends the angelic existence by comparison with different parts of time. But when we say that an angel is, or was, we suppose something, which being supposed, its opposite is not subject to the divine power. Whereas when we say he will be, we do not as yet suppose anything. Hence, since the existence and non-existence of an angel considered absolutely is subject to the divine power, God can make the existence of an angel not future; but He cannot cause him not to be while he is, or not to have been, after he has been.

Reply to Objection 4: The duration of aeviternity is infinite, forasmuch as it is not finished by time. Hence, there is no incongruity in saying that a creature is infinite, inasmuch as it is not ended by any other creature.

Articulus 5

Argumentum 1

Ad quintum sic proceditur. Videtur quod aevum non sit aliud a tempore.

Dicit enim Augustinus, VIII super Gen. Ad litt., quod deus movet creaturam spiritualem per tempus.

Sed aevum dicitur esse mensura spiritualium substantiarum.

Ergo tempus non differt ab aevo.

Argumentum 2

Praeterea, de ratione temporis est quod habeat prius et posterius, de ratione vero aeternitatis est quod sit tota simul, ut dictum est.

Sed aevum non est aeternitas, dicitur enim Eccli. I, quod sapientia aeterna est ante aevum. Ergo non est totum simul, sed habet prius et posterius, et ita est tempus.

Argumentum 3

Praeterea, si in aevo non est prius et posterius, sequitur quod in aeviternis non differat esse vel fuisse vel futurum esse. Cum igitur sit impossibile aeviterna non fuisse, sequitur quod impossibile sit ea non futura esse.

Quod falsum est, cum deus possit ea reducere in nihilum.

Argumentum 4

Praeterea, cum duratio aeviternorum sit infinita ex parte post, si aevum sit totum simul, sequitur quod aliquod creatum sit infinitum in actu, quod est impossibile.

Non igitur aevum differt a tempore.

Sed Contra

Sed contra est quod dicit boetius, qui tempus ab aevo ire iubes.

Corpus

Respondeo dicendum quod aevum differt a tempore et ab aeternitate, sicut medium existens inter illa.

Sed horum differentiam aliqui sic assignant, dicentes quod aeternitas principio et fine caret; aevum habet principium, sed non finem; tempus autem habet principium et finem.

Sed haec differentia est per accidens, sicut supra dictum est, quia si etiam semper aeviterna fuissent et semper futura essent, ut aliqui ponunt; vel etiam si quandoque deficerent, quod deo possibile esset, adhuc aevum distingueretur ab aeternitate et tempore.

Alii vero assignant differentiam inter haec tria, per hoc quod aeternitas non habet prius et posterius; tempus autem habet prius et posterius cum innovatione et veteratione; aevum habet prius et posterius sine innovatione et veteratione.

Sed haec positio implicat contradictoria. Quod quidem manifeste apparet, si innovatio et veteratio referantur ad ipsam mensuram.

Cum enim prius et posterius durationis non possint esse simul, si aevum habet prius et posterius, oportet quod, priore parte aevi recedente, posterior de novo adveniat, et sic erit innovatio in ipso aevo, sicut in tempore. Si vero referantur ad mensurata, adhuc sequitur inconveniens. Ex hoc enim res temporalis inveteratur tempore, quod habet esse transmutabile, et ex transmutabilitate mensurati, est prius et posterius in mensura, ut patet ex IV physic..

Si igitur ipsum aeviternum non sit inveterabile nec innovabile, hoc erit quia esse eius est intransmutabile. Mensura ergo eius non habebit prius et posterius.

Est ergo dicendum quod, cum aeternitas sit mensura esse permanentis, secundum quod aliquid recedit a permanentia essendi, secundum hoc recedit ab aeternitate. Quaedam autem sic recedunt a permanentia essendi, quod esse eorum est subiectum transmutationis, vel in transmutatione consistit, et huiusmodi mensurantur tempore; sicut omnis motus, et etiam esse omnium corruptibilium. Quaedam vero recedunt minus a permanentia essendi, quia esse eorum nec in transmutatione consistit, nec est subiectum transmutationis, tamen habent transmutationem adiunctam, vel in actu vel in potentia. Sicut patet in corporibus caelestibus, quorum esse substantiale est intransmutabile; tamen esse intransmutabile habent cum transmutabilitate secundum locum. Et similiter patet de Angelis, quod habent esse intransmutabile cum transmutabilitate secundum electionem, quantum ad eorum naturam pertinet; et cum transmutabilitate intelligentiarum et affectionum, et locorum suo modo. Et ideo huiusmodi mensurantur aevo, quod est medium inter aeternitatem et tempus. Esse autem quod mensurat aeternitas, nec est mutabile, nec mutabilitati adiunctum.

Sic ergo tempus habet prius et posterius, aevum autem non habet in se prius et posterius, sed ei coniungi possunt, aeternitas autem non habet prius neque posterius, neque ea compatitur.

Ad 1

Ad primum ergo dicendum quod creaturae spirituales, quantum ad affectiones et intelligentias, in quibus est successio, mensurantur tempore.

Unde et Augustinus ibidem dicit quod per tempus moveri, est per affectiones moveri.

Quantum vero ad eorum esse naturale, mensurantur aevo.

Sed quantum ad visionem gloriae, participant aeternitatem.

Ad 2

Ad secundum dicendum quod aevum est totum simul, non tamen est aeternitas, quia compatitur secum prius et posterius.

Ad 3

Ad tertium dicendum quod in ipso esse Angeli in se considerato, non est differentia praeteriti et futuri, sed solum secundum adiunctas mutationes. Sed quod dicimus Angelum esse vel fuisse vel futurum esse, differt secundum acceptionem intellectus nostri, qui accipit esse Angeli per comparationem ad diversas partes temporis. Et cum dicit Angelum esse vel fuisse, supponit aliquid cum quo eius oppositum non subditur divinae potentiae, cum vero dicit futurum esse, nondum supponit aliquid. Unde, cum esse et non esse Angeli subsit divinae potentiae, absolute considerando, potest deus facere quod esse Angeli non sit futurum, tamen non potest facere quod non sit dum est, vel quod non fuerit postquam fuit.

Ad 4

Ad quartum dicendum quod duratio aevi est infinita, quia non finitur tempore. Sic autem esse aliquod creatum infinitum, quod non finiatur quodam alio, non est inconveniens.