Thomas Aquinas, Summa Theologiae

Objection 1: It seems that the definition of eternity given by Boethius (De Consol. v) is not a good one: "Eternity is the simultaneously-whole and perfect possession of interminable life." For the word "interminable" is a negative one. But negation only belongs to what is defective, and this does not belong to eternity. Therefore in the definition of eternity the word "interminable" ought not to be found.

Objection 2: Further, eternity signifies a certain kind of duration. But duration regards existence rather than life. Therefore the word "life" ought not to come into the definition of eternity; but rather the word "existence."

Objection 3: Further, a whole is what has parts. But this is alien to eternity which is simple. Therefore it is improperly said to be "whole."

Objection 4: Many days cannot occur together, nor can many times exist all at once. But in eternity, days and times are in the plural, for it is said, "His going forth is from the beginning, from the days of eternity" (Micah 5:2); and also it is said, "According to the revelation of the mystery hidden from eternity" (Rm. 16:25). Therefore eternity is not omni-simultaneous.

Objection 5: Further, the whole and the perfect are the same thing. Supposing, therefore, that it is "whole," it is superfluously described as "perfect."

Objection 6: Further, duration does not imply "possession." But eternity is a kind of duration. Therefore eternity is not possession.

I answer that, As we attain to the knowledge of simple things by way of compound things, so must we reach to the knowledge of eternity by means of time, which is nothing but the numbering of movement by "before" and "after." For since succession occurs in every movement, and one part comes after another, the fact that we reckon before and after in movement, makes us apprehend time, which is nothing else but the measure of before and after in movement. Now in a thing bereft of movement, which is always the same, there is no before or after. As therefore the idea of time consists in the numbering of before and after in movement; so likewise in the apprehension of the uniformity of what is outside of movement, consists the idea of eternity.

Further, those things are said to be measured by time which have a beginning and an end in time, because in everything which is moved there is a beginning, and there is an end. But as whatever is wholly immutable can have no succession, so it has no beginning, and no end.

Thus eternity is known from two sources: first, because what is eternal is interminable---that is, has no beginning nor end (that is, no term either way); secondly, because eternity has no succession, being simultaneously whole.

Reply to Objection 1: Simple things are usually defined by way of negation; as "a point is that which has no parts." Yet this is not to be taken as if the negation belonged to their essence, but because our intellect which first apprehends compound things, cannot attain to the knowledge of simple things except by removing the opposite.

Reply to Objection 2: What is truly eternal, is not only being, but also living; and life extends to operation, which is not true of being. Now the protraction of duration seems to belong to operation rather than to being; hence time is the numbering of movement.

Reply to Objection 3: Eternity is called whole, not because it has parts, but because it is wanting in nothing.

Reply to Objection 4: As God, although incorporeal, is named in Scripture metaphorically by corporeal names, so eternity though simultaneously whole, is called by names implying time and succession.

Reply to Objection 5: Two things are to be considered in time: time itself, which is successive; and the "now" of time, which is imperfect. Hence the expression "simultaneously-whole" is used to remove the idea of time, and the word "perfect" is used to exclude the "now" of time.

Reply to Objection 6: Whatever is possessed, is held firmly and quietly; therefore to designate the immutability and permanence of eternity, we use the word "possession."

Articulus 1

Argumentum 1

Ad primum sic proceditur. Videtur quod non sit conveniens definitio aeternitatis, quam boetius ponit V de consolatione, dicens quod aeternitas est interminabilis vitae tota simul et perfecta possessio.

Interminabile enim negative dicitur. Sed negatio non est de ratione nisi eorum quae sunt deficientia, quod aeternitati non competit. Ergo in definitione aeternitatis non debet poni interminabile.

Argumentum 2

Praeterea, aeternitas durationem quandam significat.

Duratio autem magis respicit esse quam vitam. Ergo non debuit poni in definitione aeternitatis vita, sed magis esse.

Argumentum 3

Praeterea, totum dicitur quod habet partes. Hoc autem aeternitati non convenit, cum sit simplex. Ergo inconvenienter dicitur tota.

Argumentum 4

Praeterea, plures dies non possunt esse simul, nec plura tempora.

Sed in aeternitate pluraliter dicuntur dies et tempora, dicitur enim micheae V, egressus eius ab initio, a diebus aeternitatis; et ad Rom., XVI cap., secundum revelationem mysterii temporibus aeternis taciti.

Ergo aeternitas non est tota simul.

Argumentum 5

Praeterea, totum et perfectum sunt idem.

Posito igitur quod sit tota, superflue additur quod sit perfecta.

Argumentum 6

Praeterea, possessio ad durationem non pertinet. Aeternitas autem quaedam duratio est. Ergo aeternitas non est possessio.

Corpus

Respondeo dicendum quod, sicut in cognitionem simplicium oportet nos venire per composita, ita in cognitionem aeternitatis oportet nos venire per tempus; quod nihil aliud est quam numerus motus secundum prius et posterius. Cum enim in quolibet motu sit successio, et una pars post alteram, ex hoc quod numeramus prius et posterius in motu, apprehendimus tempus; quod nihil aliud est quam numerus prioris et posterioris in motu. In eo autem quod caret motu, et semper eodem modo se habet, non est accipere prius et posterius. Sicut igitur ratio temporis consistit in numeratione prioris et posterioris in motu, ita in apprehensione uniformitatis eius quod est omnino extra motum, consistit ratio aeternitatis. Item, ea dicuntur tempore mensurari, quae principium et finem habent in tempore, ut dicitur in IV physic., et hoc ideo, quia in omni eo quod movetur est accipere aliquod principium et aliquem finem. Quod vero est omnino immutabile, sicut nec successionem, ita nec principium aut finem habere potest. Sic ergo ex duobus notificatur aeternitas.

Primo, ex hoc quod id quod est in aeternitate, est interminabile, idest principio et fine carens (ut terminus ad utrumque referatur)p secundo, per hoc quod ipsa aeternitas successione caret, tota simul existens.

Ad 1

Ad primum ergo dicendum quod simplicia consueverunt per negationem definiri, sicut punctus est cuius pars non est. Quod non ideo est, quod negatio sit de essentia eorum, sed quia intellectus noster, qui primo apprehendit composita, in cognitionem simplicium pervenire non potest, nisi per remotionem compositionis.

Ad 2

Ad secundum dicendum quod illud quod est vere aeternum, non solum est ens, sed vivens, et ipsum vivere se extendit quodammodo ad operationem, non autem esse. Protensio autem durationis videtur attendi secundum operationem, magis quam secundum esse, unde et tempus est numerus motus.

Ad 3

Ad tertium dicendum quod aeternitas dicitur tota, non quia habet partes, sed inquantum nihil ei deest.

Ad 4

Ad quartum dicendum quod, sicut deus, cum sit incorporeus, nominibus rerum corporalium metaphorice in Scripturis nominatur, sic aeternitas, tota simul existens, nominibus temporalibus successivis.

Ad 5

Ad quintum dicendum quod in tempore est duo considerare, scilicet ipsum tempus, quod est successivum; et nunc temporis, quod est imperfectum.

Dicit ergo tota simul, ad removendum tempus, et perfecta, ad excludendum nunc temporis.

Ad 6

Ad sextum dicendum quod illud quod possidetur, firmiter et quiete habetur.

Ad designandam ergo immutabilitatem et indeficientiam aeternitatis, usus est nomine possessionis.