Thomas Aquinas, Summa Theologiae

Objection 1: It seems that this change is not wrought instantaneously, but successively. For in this change there is first the substance of bread, and afterwards the substance of Christ's body. Neither, then, is in the same instant, but in two instants. But there is a mid-time between every two instants. Therefore this change must take place according to the succession of time, which is between the last instant in which the bread is there, and the first instant in which the body of Christ is present.

Objection 2: Further, in every change something is "in becoming" and something is "in being." But these two things do not exist at the one time for, what is "in becoming," is not yet, whereas what is "in being," already is. Consequently, there is a before and an after in such change: and so necessarily the change cannot be instantaneous, but successive.

Objection 3: Further, Ambrose says (De Sacram. iv) that this sacrament "is made by the words of Christ." But Christ's words are pronounced successively. Therefore the change takes place successively.

On the contrary, This change is effected by a power which is infinite, to which it belongs to operate in an instant.

I answer that, A change may be instantaneous from a threefold reason. First on the part of the form, which is the terminus of the change. For, if it be a form that receives more and less, it is acquired by its subject successively, such as health; and therefore because a substantial form does not receive more and less, it follows that its introduction into matter is instantaneous.

Secondly on the part of the subject, which sometimes is prepared successively for receiving the form; thus water is heated successively. When, however, the subject itself is in the ultimate disposition for receiving the form, it receives it suddenly, as a transparent body is illuminated suddenly. Thirdly on the part of the agent, which possesses infinite power: wherefore it can instantly dispose the matter for the form. Thus it is written (Mk. 7:34) that when Christ had said, "'Ephpheta,' which is 'Be thou opened,' immediately his ears were opened, and the string of his tongue was loosed."

For these three reasons this conversion is instantaneous. First, because the substance of Christ's body which is the term of this conversion, does not receive more or less. Secondly, because in this conversion there is no subject to be disposed successively. Thirdly, because it is effected by God's infinite power.

Reply to Objection 1: Some do not grant simply that there is a mid-time between every two instants. For they say that this is true of two instants referring to the same movement, but not if they refer to different things. Hence between the instant that marks the close of rest, and another which marks the beginning of movement, there is no mid-time. But in this they are mistaken, because the unity of time and of instant, or even their plurality, is not taken according to movements of any sort, but according to the first movement of the heavens, which is the measure of all movement and rest.

Accordingly others grant this of the time which measures movement depending on the movement of the heavens. But there are some movements which are not dependent on the movement of the heavens, nor measured by it, as was said in the 1, Question 53, Article 3 concerning the movements of the angels. Hence between two instants responding to those movements there is no mid-time. But this is not to the point, because although the change in question has no relation of itself to the movement of the heavens, still it follows the pronouncing of the words, which (pronouncing) must necessarily be measured by the movement of the heavens. And therefore there must of necessity be a mid-time between every two signate instants in connection with that change.

Some say therefore that the instant in which the bread was last, and the instant in which the body of Christ is first, are indeed two in comparison with the things measured, but are one comparatively to the time measuring; as when two lines touch, there are two points on the part of the two lines, but one point on the part of the place containing them. But here there is no likeness, because instant and time is not the intrinsic measure of particular movements, as a line and point are of a body, but only the extrinsic measure, as place is to bodies.

Hence others say that it is the same instant in fact, but another according to reason. But according to this it would follow that things really opposite would exist together; for diversity of reason does not change a thing objectively.

And therefore it must be said that this change, as stated above, is wrought by Christ's words which are spoken by the priest, so that the last instant of pronouncing the words is the first instant in which Christ's body is in the sacrament; and that the substance of the bread is there during the whole preceding time. Of this time no instant is to be taken as proximately preceding the last one, because time is not made up of successive instants, as is proved in Phys. vi. And therefore a first instant can be assigned in which Christ's body is present; but a last instant cannot be assigned in which the substance of bread is there, but a last time can be assigned. And the same holds good in natural changes, as is evident from the Philosopher (Phys. viii).

Reply to Objection 2: In instantaneous changes a thing is "in becoming," and is "in being" simultaneously; just as becoming illuminated and to be actually illuminated are simultaneous: for in such, a thing is said to be "in being" according as it now is; but to be "in becoming," according as it was not before.

Reply to Objection 3: As stated above (ad 1), this change comes about in the last instant of the pronouncing of the words. for then the meaning of the words is finished, which meaning is efficacious in the forms of the sacraments. And therefore it does not follow that this change is successive.

Articulus 7

Argumentum 1

Ad septimum sic proceditur. Videtur quod ista conversio non fiat in istanti, sed fiat successive. In hac enim conversione prius est substantia panis, et postea substantia corporis christi. Non ergo utrumque est in eodem instanti, sed in duobus instantibus.

Sed inter quaelibet duo instantia est tempus medium. Ergo oportet quod haec conversio fiat secundum successionem temporis quod est inter ultimum instans quo est ibi panis, et primum instans quo est ibi corpus christi.

Argumentum 2

Praeterea, in omni conversione est fieri et factum esse. Sed haec duo non sunt simul, quia quod fit, non est; quod autem factum est, iam est. Ergo in hac conversione est prius et posterius.

Et ita oportet quod non sit instantanea, sed successiva.

Argumentum 3

Praeterea, Ambrosius dicit, in libro de sacram., quod istud sacramentum christi sermone conficitur.

Sed sermo christi successive profertur. Ergo haec conversio fit successive.

Sed Contra

Sed contra est quod haec conversio perficitur virtute infinita, cuius est subito operari.

Corpus

Respondeo dicendum quod aliqua mutatio est instantanea triplici ratione. Uno quidem modo, ex parte formae, quae est terminus mutationis. Si enim sit aliqua forma quae recipiat magis aut minus, successive acquiritur subiecto, sicut sanitas. Et ideo, quia forma substantialis non recipit magis et minus, inde est quod subito fit eius introductio in materia. Alio modo, ex parte subiecti, quod quandoque successive praeparatur ad susceptionem formae, et ideo aqua successive calefit. Quando vero ipsum subiectum est in ultima dispositione ad formam, subito recipit ipsam, sicut diaphanum subito illuminatur. Tertio, ex parte agentis, quod est infinitae virtutis, unde statim potest materiam ad formam disponere.

Sicut dicitur Marc. VII, quod, cum christus dixisset, ephphetha, quod est adaperire, statim apertae sunt aures hominis, et solutum est vinculum linguae eius.

Et his tribus rationibus haec conversio est instantanea.

Primo quidem, quia substantia corporis christi, ad quam terminatur ista conversio, non suscipit magis neque minus. Secundo, quia in hac conversione non est aliquod subiectum, quod successive praeparetur. Tertio, quia agitur dei virtute infinita.

Ad 1

Ad primum ergo dicendum quod quidam non simpliciter concedunt quod inter quaelibet duo instantia sit tempus medium. Dicunt enim quod hoc habet locum in duobus instantibus quae referuntur ad eundem motum, non autem in duobus instantibus quae referuntur ad diversa. Unde inter instans quod mensurat finem quietis, et aliud instans quod mensurat principium motus, non est tempus medium.

Sed in hoc decipiuntur. Quia unitas temporis et instantis, vel etiam pluralitas eorum, non accipitur secundum quoscumque motus, sed secundum primum motum caeli, qui est mensura omnis motus et quietis.

Et ideo alii hoc concedunt in tempore quod mensurat motum dependentem ex motu caeli. Sunt autem quidam motus ex motu caeli non dependentes, nec ab eo mensurati, sicut in prima parte dictum est de motibus Angelorum.

Unde inter duo instantia illis motibus respondentia, non est tempus medium.

Sed hoc non habet locum in proposito. Quia, quamvis ista conversio secundum se non habeat ordinem ad motum caeli, consequitur tamen prolationem verborum, quam necesse est motu caeli mensurari.

Et ideo necesse est inter quaelibet duo instantia circa istam conversionem signata esse tempus medium.

Quidam ergo dicunt quod instans in quo ultimo est panis, et instans in quo primo est corpus christi, sunt quidem duo per comparationem ad mensurata, sed sunt unum per comparationem ad tempus mensurans, sicut, cum duae lineae se contingunt, sunt duo puncta ex parte duarum linearum, unum autem punctum ex parte loci continentis.

Sed hoc non est simile. Quia instans et tempus particularibus motibus non est mensura intrinseca, sicut linea et punctus corporibus, sed solum extrinseca, sicut corporibus locus.

Unde alii dicunt quod est idem instans re, sed aliud ratione.

Sed secundum hoc sequeretur quod realiter opposita essent simul.

Nam diversitas rationis non variat aliquid ex parte rei.

Et ideo dicendum est quod haec conversio, sicut dictum est, perficitur per verba christi, quae a sacerdote proferuntur, ita quod ultimum instans prolationis verborum est primum instans in quo est in sacramento corpus christi, in toto autem tempore praecedente est ibi substantia panis. Cuius temporis non est accipere aliquod instans proximo praecedens ultimum, quia tempus non componitur ex instantibus consequenter se habentibus, ut probatur in VI physic..

Et ideo est quidem dare instans in quo est corpus christi, non est autem dare ultimum instans in quo sit substantia panis, sed est dare ultimum tempus. Et idem est in mutationibus naturalibus, ut patet per philosophum, in VIII physicorum.

Ad 2

Ad secundum dicendum quod in mutationibus instantaneis simul est fieri et factum esse, sicut simul est illuminari et illuminatum esse. Dicitur enim in talibus factum esse secundum quod iam est, fieri autem, secundum quod ante non fuit.

Ad 3

Ad tertium dicendum quod ista conversio, sicut dictum est, fit in ultimo instanti prolationis verborum, tunc enim completur verborum significatio, quae est efficax in sacramentorum formis.

Et ideo non sequitur quod ista conversio sit successiva.