Cursus Philosophicus Thomisticus, Prima Pars Artis Logicae

We defined supposition in the text as “the taking of a term for something of which it is verified according to the requirement of the copula.” For its precise explanation, therefore, THREE questions must be investigated: First, concerning its genus, how it is understood that supposition is a taking. Second, concerning its difference, how a term is verified according to the requirement of the copula. Third, whether supposition is found only within a proposition.

First difficulty. Regarding the first point, “taking” in the definition of supposition means the passive use or ordering of the intellect by which it uses some term, or orders and compares it in relation to something.

It is clear that supposition is distinguished from signification: the signification of a term is permanent and one, while its supposition can vary while the same signification remains, because the former depends on imposition, which does not change, and the latter on the application and use of the intellect, by which it applies and uses a term. Since this taking is a passive use of the term that supposits and is taken, it necessarily requires an active taking, which is nothing other than an act of the intellect ordering and comparing the term itself and consequently denominating it not only as known, but also as thus directed, applied, and taken. The very relation of reason in which the intention of supposition formally consists is founded on this passive taking.

Second, taking as such is common to the many and various intentions founded upon taking, such as the character of predicate and subject, and the character of ampliation, restriction, appellation, and the like. All these are founded upon some taking by the intellect, that is, some ordering and comparison by which it compares a term according to different considerations and characters: either by comparing one term with another under the character of subject and predicate, which are relations of that of which something is said and that which is said of something; or under the character of application, by which the signified content of one term determines that of another, as in appellation; or by comparing a term with that for which it stands, as in supposition; or with those things to which it is extended or from which it is restricted, as in ampliation and restriction. Therefore, this taking by the intellect, which is posited as the genus of supposition, is nothing other than the intellect’s ordering of a term—not so that it may signify (for this is done by imposition, not by the taking of a term), nor so that it may construct a proposition absolutely (for that belongs to the term’s exercise in the character of a part), but so that it may be coordinated and applied, according to different relations and uses, with other terms and with the whole proposition.

BUT AN OBJECTION IS RAISED, because if taking is common to every intention founded on the intellect’s passive use, such as the intention of predicate and subject, appellation, ampliation, and so on, then taking should have been placed as the genus in the definitions of all these intentions, and not only in the definition of supposition. Indeed, it should have been placed in the definition of sign, since a sign too is taken for what it signifies and stands for. Or, if taking is not the genus with respect to these, neither is it with respect to supposition.

It is also confirmed: in the proposition “The divine essence is the Father,” the expression “divine essence” is taken for the Father, yet it does not supposit for him; therefore, the definition is bad. The major premise is proved because if it were taken for the Son, or the Holy Spirit, or the whole Trinity, the proposition would be false; therefore, it is taken for the Father alone. The minor premise is proved: if it supposits for the Father, this proposition could be conceded: “The divine essence generates,” since it supposits for the Father, who generates, just as “a human being walks” is conceded because Peter walks, for whom “human being” supposits, although it does not directly signify Peter, just as the divine essence does not directly signify the Father.

It is confirmed a second time: in a closed book a term supposits, since a written proposition is found there; therefore, supposition too is found there. Yet the term is not passively taken by the intellect there, as though in act, because it is not actually known. Therefore, the essence of supposition does not consist in the intellect’s actual use and taking.

We answer that in the case of other properties or intentions founded on the intellect’s passive use, “taking” is always understood. For example, when one says “Appellation is the application of the formal signified content,” the sense is that it is an applicative taking. When one says that ampliation is an extension, an extensive taking is understood. “Taking” is expressed more readily in supposition than in the other cases because, since it is the first among these logical properties belonging to a term within a proposition, its common character could be expressed by no other name. The other properties, however, which are like additions that extend, restrict, modify, and so on, can be expressed by other names. A sign is not taken or made to stand for what it signifies by the kind of taking of which we speak here; it stands for it only by presenting or signifying it through imposition or representation. Here, however, we are speaking of a taking of the signifying term that is, as it were, applicative and ordering it to some use of the intellect.

To the first confirmation we answer that, as St. Thomas says in Summa theologiae I, q. 39, a. 5, ad 4, the divine essence does not supposit for the Father by reason of its mode of signifying (which is especially considered in the verification of an utterance), since it is signified as abstracted from the persons; but by reason of identity and supreme simplicity it can supposit for the Father or be verified of him. Therefore, when identity is signified by the verb “is,” the divine essence is taken and supposits for the person by reason of identity. But when a notional act proper to a person is signified, the expression “essence” does not supposit for the person, because identity is then not signified, but rather the person’s property, from which “essence” abstracts by its mode of signifying.

To the second confirmation we answer that in a closed book a proposition, supposition, and the other logical properties are found as it were in a sign not actually known; therefore, those intentions are present there only virtually, not actually. One must not, however, concede in the same way that a sign is there virtually and not formally, because the writing itself in the closed book is formally imposed in itself to signify, just as spoken words are. Thus, although the writing does not actually represent, it is actually imposed, and is therefore actually a sign, since the actual essence of a sign does not consist in the actual exercise of representing: a sign is said to be representative, not representation. Supposition, however, is founded on the intellect’s actual application and use. Although the relation of reason of a sign found in a closed book does not actually exist unless it is actually known, the book is nevertheless denominated a sign from the imposition itself and the proximate foundation of this relation. We shall say more about this in Logic, q. 21.

Second difficulty. To answer the second difficulty posed at the outset, which concerns the difference of supposition—namely, that it is “a taking for something for which it is verified”—we must note that, as we said,¹ the verification of a term differs from the verification of a proposition. A proposition can fail to be verified, as in “A human being is a stone,” and yet its terms truly supposit and are verified. Thus the verification of a proposition is taken according to whether the thing itself exists or does not exist, as signified by the proposition’s being or not being. To verify a supposing term, however, it suffices that what it supposits for can be found and designated according to the requirement of the copula and verb to which it is applied in supposing, as we explained more fully in the cited place. This verification or designation can sometimes be made by sense, if the thing can be demonstrated to the senses, or by the intellect, if it is hidden or considered in the abstract, as we said there. Indeed, sometimes demonstration cannot be made immediately in the term itself, but only mediately, by resolving it. For example, when I say “Every human being is an animal,” I should not demonstrate something that is “every human being”; rather, after resolving that universal into its singular instances—“This human being is an animal, and that one,” and so on—one can demonstrate of each: “This is a human being.”

Given this, some recent authors do not admit supposition in this sense: that a term must be verified for something according to the requirement of the copula. It remains for us only to prove that it must be admitted in this way.

AND THE FOUNDATION IS this: there are propositions with a subject that does not supposit, namely, when some restriction or a term incompatible with it is added to a term, as in “A corporeal angel moves” or “A created God understands.” The terms “angel” and “God” do not supposit, because there is no corporeal angel or created God. This is because, for a term to stand for something, it must not be impeded or opposed by anything, so that it can stand for that thing. Likewise, if it is incompatible with a copula to find what a term stands for, the term cannot stand for it while that copula remains. For example, if you say “Adam exists” or “The Antichrist existed,” there is no such Antichrist that existed, nor such Adam who exists; therefore, the term cannot stand for him. Verification of the term according to the copula is therefore required for standing or supposition: that is, what the term supposits for must be findable and designable according to the signification of that copula.

BUT YOU WILL SAY: In some propositions the subject supposits and is not verified according to the copula; therefore, and so on.

The antecedent is proved first in false propositions such as “Adam exists” and “The Antichrist existed.” Those propositions are false because their predicates do not belong to the things for which their subjects supposit; otherwise, we would not understand the proposition’s falsity unless we knew what the predicate is incompatible with or does not belong to. Therefore, the subject supposits for something. Also, in the proposition “A chimera will exist,” “chimera” supposits, since it is amplified by the verb “will exist,” and ampliation is an extension from lesser to greater supposition; yet it is not verified according to the copula that a chimera will ever exist. Therefore, supposition and ampliation can stand without verification. Second, in optative and imperative propositions terms can supposit, because they are said determinately of something, and yet they are not verified according to any copula, since there is none there. Finally, in propositions of eternal truth, such as “A human being is an animal,” the term cannot be verified by demonstrating it with the pronoun “this” at some temporal difference, since the verb is released from all time; therefore, supposition without verification is given.

It is confirmed: verification of a term is made by a proposition distinct from the one in which the term supposits, as we said. Therefore, such verification cannot belong to the constitutive and essential difference of supposition.

We answer: the antecedent is denied. To the first proof we say that those propositions are false precisely because they have a subject that does not supposit: according to that copula, nothing is found for which the subject supposits. Falsity does not always require that a term supposit for something to which the predicate does not belong; it suffices that it does not supposit—that is, that nothing is found under that copula—and yet a predicate is affirmed of it. In “A chimera will exist,” either there is no ampliation properly speaking, because there is no true supposition, or, if there is ampliation, it should not be taken as a greater extension of supposition, but as an extension of supposita or times to which ampliation is made, whether or not the term supposits.

To the second proof we answer that in optative utterances and so on, terms supposit according to the requirement of the copula. In optatives, if they concern the future, the term on the subject side is verified for something that exists or will exist. For example, if you say “Would that Peter become just,” “Peter” supposits for Peter, who exists or will exist. If it concerns the past, as in “Would that he had been just,” it supposits for one who exists or existed, and so on. In imperatives it supposits for something present: if you say “Peter, do this,” “Peter” must supposit for the one present to whom the command is given; the same applies to vocatives and so on. Thus an utterance containing a copula suffices for supposition, according to whose requirement the term can be found and demonstrated. In this way we understand that supposition occurs only in a proposition, taking “proposition” to mean every utterance consisting of a copula. In natural supposition, where truth abstracts from time, verification of the supposing subject is not demonstrated to the senses but to the intellect, because it is verified according to the existence expressed by a verb abstracting from time. For example, if you say “Peter is a human being,” “Peter” supposits by demonstrating Peter to the intellect in himself, as when one says “that which is Peter,” with “is” abstracting from time. When I say “A human being is an animal,” one demonstrates to the intellect that which is a human being in itself, not according to an individual or universal state.

To the confirmation we answer that verification of the term does not constitute supposition insofar as it is made, as it were, in signified act and demonstrated through another proposition; rather, verification in exercised act takes place in the very proposition in which the term supposits, and is afterwards made clear and proved in a distinct proposition.

Third difficulty. To the third difficulty posed at the outset, we answer that a term in no way supposits outside a proposition or utterance containing a copula, according to whose requirement the taking of the term can be verified.

THE REASON IS TAKEN FROM WHAT HAS BEEN SAID, because supposition is not standing for something according to the mere character of signification (for then it would clearly be found outside a proposition); rather, with signification presupposed, a term stands for something according to its application and relation to another. For it truly to supposit, therefore, what it supposits for must be found and capable of being designated in this way; otherwise, if it is neither found nor designable, it cannot be applied in such a standing-for. That what the term supposits for can be found or designated is established by demonstrating it through a copula, because by reason of a verb it is established that the thing is or is not, or that what a term supposits for is found. A term must therefore necessarily be joined to a verb, so that with respect to it what the term is taken for can be found and demonstrated. Moreover, a term can stand for something with respect to one copula and not another. For example, if you say “Adam existed,” “Adam” supposits with respect to the past. If you say “Adam exists,” it does not supposit, because he is not found and consequently is not verified with respect to the present. Sometimes supposition also varies according to the copula taken not absolutely, but with respect to the predicate. For example, in “A human being is a noun” and “A human being is a species,” “human being” does not supposit by reason only of the copula “is,” as signifying present time; rather, it is understood to supposit materially in one and simply in the other, because the predicate joined to the term by that copula requires it. Therefore, different species of supposition can be taken in relation to different copulas.

BUT YOU WILL OBJECT: A term outside a proposition truly has the character of a term and a part; therefore, it expresses a relation to the verb, by joining with which it can compose; therefore, it has the character of supposition, just as it has a proximate potency for composition. For just as a term signifies potency, not act, for composing, so too for supposing, especially since supposition is a property of a term and consequently is not separated from it, either within or outside a proposition.

It is also confirmed, because outside a proposition a term expresses a relation to a verb or to another term. First, in imperfect utterances, as when you say “Peter, white” or “a just human being,” where one term can be taken in relation to another. Why should it be taken only in relation to a verb? Also, in complete non-enunciative utterances, which truly and properly contain a verb, though they do not enunciate but command, wish, and so on.

It is confirmed a second time: if a term supposits only within a proposition because it stands for something according to the requirement of the verb, it follows that all true affirmative propositions are essential. This is clear in the proposition “Peter runs,” which is true because according to the requirement of the copula it supposits for a running Peter. But it is essential to say of a running Peter that he runs; therefore, this is an essential proposition.

We answer the principal argument: there is a difference between the character of a term and the character of supposition. The intention of a term is only the intention of a part and the substitution of signification. Neither is founded on the actual exercise of signifying or composing, but on the ability and potency to compose or signify. For the character of a part is not the character of what is composing, but of what is compositive; similarly, the character of a sign is that of what is significant, not what is signifying. The intention of supposition, however, results from the intellect’s actual determination and passive use of a term, which it determines and applies, whether in the mind, in speech, or in writing, for this or that for which it is verified. Therefore, before the intellect’s actual application, this determination is not given. As to the claim that supposition is a property of a term, I answer that supposition is not a property of a term in every state, but only insofar as it is applied within a proposition, just as it is a property of a heavy thing to rest not absolutely, but at the center.

To the first confirmation we answer that outside a proposition a term expresses a relation to a verb or predicate in the manner of a part capable of composing, not in the manner of an act determined and made to stand for something that is truly found to stand for it. For it cannot be established that it truly stands for something in this way unless it is established with respect to a verb that it is found. Hence there is no supposition in imperfect utterances that do not contain a verb, because what is needed to verify and designate how a term truly and properly supposits is not yet given. This is evident because when terms are joined without a verb, as in “A white human being,” that complex is indifferent to every kind of supposition. From it one can form material supposition by saying “A white human being is a complex expression”; formal supposition by saying “A white human being scatters vision”; simple supposition by saying “A white human being is predicable of many”; natural supposition by saying “A white human being is colored”; or accidental supposition by saying “A white human being walks.” Since it is indifferent to all species of supposition, it clearly has none in act and is not determined and verified by reason of a copula. We have already said that supposition can be found in non-enunciative utterances containing a verb.

To the second confirmation we answer that although in that proposition “Peter” supposits identically for a running Peter, the proposition is not essential. For an essential proposition requires more than the identity of subject and predicate on the side of the supposited thing and its supposition; it also requires a necessary connection and relation of the terms, which is an identity, as it were, formal. Thus in the accidental propositions mentioned there is indeed a true conjunction and union between predicate and subject, but it is not necessary. Although they supposit for the same thing, they do not do so under the formality of the necessary connection required for an essential proposition, as would be formally signified on the subject side by saying “A running Peter runs.” For then the proposition would be essential, because the relation of the terms would signify not only the foundation of truth but intrinsic necessity.