i. But since two contrary forms are of themselves diverse, as being

the principles of formal difference, so two signate matters are of themselves diverse, as being the principles of material distinction. Consequently, it is not possible for this matter of bread to become this matter whereby Christ's body is individuated, and so it is not possible for this substance of bread to be changed into the substance of Christ's body.

_On the contrary,_ Eusebius Emesenus says: "To thee it ought neither to be a novelty nor an impossibility that earthly and mortal things be changed into the substance of Christ."

_I answer that,_ As stated above (A. 2), since Christ's true body is in this sacrament, and since it does not begin to be there by local motion, nor is it contained therein as in a place, as is evident from what was stated above (A. 1, ad 2), it must be said then that it begins to be there by conversion of the substance of bread into itself.

Yet this change is not like natural changes, but is entirely supernatural, and effected by God's power alone. Hence Ambrose says [(De Sacram. iv): "See how Christ's word changes nature's laws, as He wills: a man is not wont to be born save of man and woman: see therefore that against the established law and order a man is born of a Virgin": and] [*The passage in the brackets is not in the Leonine edition] (De Myster. iv): "It is clear that a Virgin begot beyond the order of nature: and what we make is the body from the Virgin. Why, then, do you look for nature's order in Christ's body, since the Lord Jesus was Himself brought forth of a Virgin beyond nature?" Chrysostom likewise (Hom. xlvii), commenting on John 6:64: "The words which I have spoken to you," namely, of this sacrament, "are spirit and life," says: i.e. "spiritual, having nothing carnal, nor natural consequence; but they are rent from all such necessity which exists upon earth, and from the laws here established."

For it is evident that every agent acts according as it is in act. But every created agent is limited in its act, as being of a determinate genus and species: and consequently the action of every created agent bears upon some determinate act. Now the determination of every thing in actual existence comes from its form. Consequently, no natural or created agent can act except by changing the form in something; and on this account every change made according to nature's laws is a formal change. But God is infinite act, as stated in the First Part (Q. 7, A. 1; Q. 26, A. 2); hence His action extends to the whole nature of being. Therefore He can work not only formal conversion, so that diverse forms succeed each other in the same subject; but also the change of all being, so that, to wit, the whole substance of one thing be changed into the whole substance of another. And this is done by Divine power in this sacrament; for the whole substance of the bread is changed into the whole substance of Christ's body, and the whole substance of the wine into the whole substance of Christ's blood. Hence this is not a formal, but a substantial conversion; nor is it a kind of natural movement: but, with a name of its own, it can be called "transubstantiation."

Reply Obj. 1: This objection holds good in respect of formal change, because it belongs to a form to be in matter or in a subject; but it does not hold good in respect of the change of the entire substance. Hence, since this substantial change implies a certain order of substances, one of which is changed into the other, it is in both substances as in a subject, just as order and number.

Reply Obj. 2: This argument also is true of formal conversion or change, because, as stated above (ad 1), a form must be in some matter or subject. But this is not so in a change of the entire substance; for in this case no subject is possible.

Reply Obj. 3: Form cannot be changed into form, nor matter into matter by the power of any finite agent. Such a change, however, can be made by the power of an infinite agent, which has control over all being, because the nature of being is common to both forms and to both matters; and whatever there is of being in the one, the author of being can change into whatever there is of being in the other, withdrawing that whereby it was distinguished from the other. _______________________

FIFTH ARTICLE [III, Q. 75, Art. 5]

Whether the Accidents of the Bread and Wine Remain in This Sacrament After the Change?

Objection 1: It seems that the accidents of the bread and wine do not remain in this sacrament. For when that which comes first is removed, that which follows is also taken away. But substance is naturally before accident, as is proved in _Metaph._ vii. Since, then, after consecration, the substance of the bread does not remain in this sacrament, it seems that its accidents cannot remain.

Obj. 2: Further, there ought not to be any deception in a sacrament of truth. But we judge of substance by accidents. It seems, then, that human judgment is deceived, if, while the accidents remain, the substance of the bread does not. Consequently this is unbecoming to this sacrament.

Obj. 3: Further, although our faith is not subject to reason, still it is not contrary to reason, but above it, as was said in the beginning of this work (I, Q. 1, A. 6, ad 2; A. 8). But our reason has its origin in the senses. Therefore our faith ought not to be contrary to the senses, as it is when sense judges that to be bread which faith believes to be the substance of Christ's body. Therefore it is not befitting this sacrament for the accidents of bread to remain subject to the senses, and for the substance of bread not to remain.

Obj. 4: Further, what remains after the change has taken place seems to be the subject of change. If therefore the accidents of the bread remain after the change has been effected, it seems that the accidents are the subject of the change. But this is impossible; for "an accident cannot have an accident" (Metaph. iii). Therefore the accidents of the bread and wine ought not to remain in this sacrament.

_On the contrary,_ Augustine says in his book on the Sentences of Prosper (Lanfranc, De Corp. et Sang. Dom. xiii): "Under the species which we behold, of bread and wine, we honor invisible things, i.e. flesh and blood."

_I answer that,_ It is evident to sense that all the accidents of the bread and wine remain after the consecration. And this is reasonably done by Divine providence. First of all, because it is not customary, but horrible, for men to eat human flesh, and to drink blood. And therefore Christ's flesh and blood are set before us to be partaken of under the species of those things which are the more commonly used by men, namely, bread and wine. Secondly, lest this sacrament might be derided by unbelievers, if we were to eat our Lord under His own species. Thirdly, that while we receive our Lord's body and blood invisibly, this may redound to the merit of faith.

Reply Obj. 1: As is said in the book _De Causis,_ an effect depends more on the first cause than on the second. And therefore by God's power, which is the first cause of all things, it is possible for that which follows to remain, while that which is first is taken away.

Reply Obj. 2: There is no deception in this sacrament; for the accidents which are discerned by the senses are truly present. But the intellect, whose proper object is substance as is said in _De Anima_ iii, is preserved by faith from deception.

And this serves as answer to the third argument; because faith is not contrary to the senses, but concerns things to which sense does not reach.

Reply Obj. 4: This change has not properly a subject, as was stated above (A. 4, ad 1); nevertheless the accidents which remain have some resemblance of a subject. _______________________

SIXTH ARTICLE [III, Q. 75, Art. 6]

Whether the Substantial Form of the Bread Remains in This Sacrament After the Consecration?

Objection 1: It seems that the substantial form of the bread remains in this sacrament after the consecration. For it has been said (A. 5) that the accidents remain after the consecration. But since bread is an artificial thing, its form is an accident. Therefore it remains after the consecration.

Obj. 2: Further, the form of Christ's body is His soul: for it is said in _De Anima_ ii, that the soul "is the act of a physical body which has life in potentiality". But it cannot be said that the substantial form of the bread is changed into the soul. Therefore it appears that it remains after the consecration.

Obj. 3: Further, the proper operation of a things follows its substantial form. But what remains in this sacrament, nourishes, and performs every operation which bread would do were it present. Therefore the substantial form of the bread remains in this sacrament after the consecration.

_On the contrary,_ The substantial form of bread is of the substance of bread. But the substance of the bread is changed into the body of Christ, as stated above (AA. 2, 3, 4). Therefore the substantial form of the bread does not remain.

_I answer that,_ Some have contended that after the consecration not only do the accidents of the bread remain, but also its substantial form. But this cannot be. First of all, because if the substantial form of the bread were to remain, nothing of the bread would be changed into the body of Christ, excepting the matter; and so it would follow that it would be changed, not into the whole body of Christ, but into its matter, which is repugnant to the form of the sacrament, wherein it is said: "This is My body."

Secondly, because if the substantial form of the bread were to remain, it would remain either in matter, or separated from matter. The first cannot be, for if it were to remain in the matter of the bread, then the whole substance of the bread would remain, which is against what was said above (A. 2). Nor could it remain in any other matter, because the proper form exists only in its proper matter. But if it were to remain separate from matter, it would then be an actually intelligible form, and also an intelligence; for all forms separated from matter are such.

Thirdly, it would be unbefitting this sacrament: because the accidents of the bread remain in this sacrament, in order that the body of Christ may be seen under them, and not under its proper species, as stated above (A. 5).

And therefore it must be said that the substantial form of the bread does not remain.

Reply Obj. 1: There is nothing to prevent art from making a thing whose form is not an accident, but a substantial form; as frogs and serpents can be produced by art: for art produces such forms not by its own power, but by the power of natural energies. And in this way it produces the substantial forms of bread, by the power of fire baking the matter made up of flour and water.

Reply Obj. 2: The soul is the form of the body, giving it the whole order of perfect being, i.e. being, corporeal being, and animated being, and so on. Therefore the form of the bread is changed into the form of Christ's body, according as the latter gives corporeal being, but not according as it bestows animated being.

Reply Obj. 3: Some of the operations of bread follow it by reason of the accidents, such as to affect the senses, and such operations are found in the species of the bread after the consecration on account of the accidents which remain. But some other operations follow the bread either by reason of the matter, such as that it is changed into something else, or else by reason of the substantial form, such as an operation consequent upon its species, for instance, that it "strengthens man's heart" (Ps. 103:15); and such operations are found in this sacrament, not on account of the form or matter remaining, but because they are bestowed miraculously upon the accidents themselves, as will be said later (Q. 77, A. 3, ad 2, 3; AA. 5, 6). _______________________

SEVENTH ARTICLE [III, Q. 75, Art. 7]

Whether This Change Is Wrought Instantaneously?

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.

Obj. 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.

Obj. 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 Obj. 1: Some [*Cf. Albert the Great, Sent. iv, D, 11; St. Bonaventure, Sent., iv, D, 11] 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 First Part (Q. 53, A. 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._