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Kriterion: Revista de Filosofia

Print version ISSN 0100-512X

Kriterion vol.3 Belo Horizonte  2007


Predication and judgment in Aquinas


Predicação e juízo em Tomás de Aquino



Raul Landim Filho

Professor of the Department of Philosophy of the Universidade Federal do Rio de Janeiro and CNPq Researcher.

Translated by David Rodgers
Translation from Kriterion, Belo Horizonte, v.47, n.113, p. 27-49, 2006.




In this article, I present an interpretation of Thomas Aquinas's theory of judgment (statement), examining semantic, epistemological and ontological aspects of this theory. Elements of judgment such as concepts, phantasms, predication (combination and division), reflection, affirmation, truth and falsity are explained. The article shows that this interpretation of Aquinas's theory of judgment may contribute to clarify fundamental distinctions (such as the distinctions between being, essence and existence) of Aquinas's metaphysics.

Keywords: Concept, Predication, Reflection, Affirmation, Judgment


Neste artigo, pretendemos expor uma interpretação da teoria tomásica do juízo assertórico (enunciado), analisando os aspectos semânticos, epistêmicos e ontológicos dessa teoria. São explicitados os elementos constitutivos do juízo: conceito, imagem, predicação (composição e divisão), reflexão, afirmação, negação, verdadeiro e falso. O artigo mostra que, interpretada dessa forma, a teoria do juízo pode contribuir para o esclarecimento das distinções que serão tematizadas pela metafísica tomásica: as distinções entre ser, ente, essência e existência.

Palavras-chave: Conceito, Predicação, Reflexão, Afirmação, Juízo



Over the course of the 20th century, neo-Thomism focused special attention on Thomas Aquinas's theory of judgment. 1 The reasons for this emphasis were manifold and frequently divergent: some interpretations sought to show that the intellectual act of judgment is the starting point of metaphysics;2 other interpretations, stimulated by different concerns, argued that the central notion of Thomistic metaphysics is being (esse) and not being (ens), and that unlike being (ens), the notion of being (esse) cannot be captured by a simple conceptual apprehension of an essence, but only by a judgment.3 Still other interpretations, derived from the conceptual framework of analytic philosophy, attempted to reconcile the Thomistic analysis of judgment with contemporary philosophical logic, lending a surprisingly modern form to a number of Aquinas's ideas on semantics that had fallen into disuse.4

In this article, I intend to provide a synthetic exposition of the Thomistic theory of judgment,5 which may be thought a somewhat hazardous enterprise given the multiplicity of semantic, epistemological and ontological aspects involved. Indeed, it is the very subtly of this theory that poses this risk.


1. Linguistic analysis: noun, verb and statement

In Thomistic philosophy the term 'judgment' has a number of meanings.6 The notion of judgment analyzed in this article is that of the judgment that composes and divides, since only in this sense can judgments through affirmation or negation be held to possess a truth value.

Judgments by composition or division are mental acts. So how, then, do we analyze them?

Thomas Aquinas assumes the validity of the famous semantic triangle7 formulated by Aristotle8 in De interpretatione: written marks conventionally denote spoken sounds, which, for their part, conventionally denote affections of the soul (concepts, in Aquinas's terminology) which by nature are likenesses of things. A written or oral sign that is simple (without significant parts) and conventionally denotes, in an atemporal form, concepts (which, for their part, are likenesses of things) is called a noun. A simple sign that conventionally denotes actions or properties in a temporal form is called a verb. Verbs are signs of things said of some other thing.9 For this reason, they are incomplete expressions, insofar as they demand the complement of a noun in order to form predicative sentence.

Aquinas's analysis of nouns and verbs, mirroring Aristotle's De interpretatione, oscillates between a merely grammatical characterization of these expressions10 (where a noun comprises a conventional oral sign without significant parts, etc.)  and a functional characterization: nouns perform the function of the subject of a predicative sentence, verbs that of predicates; subjects have the function of mentioning things, predicates that of characterizing them.11 Although subject and predicate are logically heterogenic and complementary functions, nouns can perform the function of predicates, while verbs (at least in infinitive and participle forms) can perform the function of subjects. These ambiguities, which stem from the fact that the noun cannot be identified with the function of subject, nor the verb with that of the predicate, have repercussions for Aquinas's analysis of the verb 'to be' (esse) in his commentary to De interpretatione:12 being may be interpreted as a noun, signifying being (ens) (that which is, quod est) and hence signifying things (objects). Alternatively, it may be interpreted as a predicate, and hence signifying properties of things, whether as part of a complex predicate, expressing the inherence of properties in things mentioned by the subject (to be as a copula),13 or as a simple predicate, signifying the factual existence of things mentioned by the subject (to be as factual existence).14 Finally, these semantic considerations suggest a 'metaphysical' analysis: being (esse) may signify the act by which something (the being [ens]) is.15

In contrast to nouns and verbs, sentences are complex conventional expressions, since their parts, taken in isolation, are significant. But connecting or applying a verb to a noun forms a predicative sentence, since to predicate is to attribute a property to a thing. Nouns and verbs are 'grammatical terms', but in a predicative sentence, nouns primarily perform the logical function of subjects; verbs, the function of predicates. The noun-subject signifies (via a concept) a thing (object), which is characterized by a property signified by the verb-predicate.16 Hence, there is no simple predication without composition of the predicate with the subject (the verb with the noun). Predicative sentences with a truth value are called statements. Noun/verb and statement provide a linguistic expression of mental operations, which Aquinas denominates understanding of indivisibles and judgment by composition and division. Thanks to the correspondence between linguistic operations and the corresponding operations of the intellect, it is possible to analyze acts of judgment linguistically without resorting to introspective methods.


2. General terms and concepts

Aquinas states that to know is to judge: "Dicendum, quod in qualibet cognitione duo est considerare, scilicet principium et terminum. Principium quidem ad appreensionem pertinet, terminus autem ad iudicium: ibi enim cognitio perficitur."17

In Aquinas´s Commentary on the De Trinitate, as well as affirming that knowledge is only realized through judgment, he also distinguishes the two operations of the intellect mentioned above: apprehension and judgment. In various other texts,18 Aquinas explores this distinction and calls them the understanding of indivisibles (first operation of the intellect) and composition and division (second operation of the intellect). The understanding of indivisibles, commonly called quidditative apprehension by the Thomist tradition, is a condition for realizing the second operation of composing and dividing, which, under certain conditions, formally expresses the realization of the cognitive act. Note that the second operation is not called judgment, since, under certain aspects, the senses also judge, although only the intellect judges by composition and division.19

The analysis of this double operation will be the guiding thread for this part of the article.

The understanding of indivisibles has a double aspect: it comprises both the intellection of a thing's whatness or quiddity (in a broad sense of quiddity or essence),20 and the formation or production of concepts through the apprehension of the whatness of a thing.

Abstraction21 allows us to know the quiddity, whether by abstraction of the whole from the particular (which Aquinas calls the abstraction of the whole, abstractio totius, abstraction without precision – or exclusion – of the residues from which it abstracts), or abstraction of the form (abstraction formae a material sensibili).22 Quiddity is extracted from the phantasm (or sensible image) by the action of the agent intellect thanks to an abstractive process that leaves out the individualizing conditions of the content presented by the phantasm. It is impressed on the possible intellect. Taken in itself, that is, considered absolutely without relation to the phantasm from which it was abstracted or to the individual who singularizes it or to the concept that expresses it, quiddity is neither single nor multiple, neither singular nor universal, since its mode of existence has been left out. It is obtained by abstraction without exclusion of the individuating conditions. In De ente, Aquinas calls the quiddity thus obtained nature absolutely considered.23

In this case, essence or quiddity has been considered by abstraction of its modes of existence. Indeed, essence exists in singular things or is expressed by the concept in a universal mode in the mind. It can be analyzed as an essence of particular things and, in this case, can be considered the essence of something either possible or actual. It can also be expressed by a universal concept. But if its mode of existence has been left aside, it in itself is neither singular nor universal.

On the basis of the apprehended quiddity, the intellect forms or produces concepts that are intentional beings existing in the intellect in a universal mode. These are expressed by definitions, which make explicit the different aspects of quiddity through intelligible marks. Thus the concept, or at least the concept called a direct universal by the Scholastics, expresses in the mind a nature absolutely considered, the quiddity or nature of the thing apprehended, with an intention of universality (intentio universalitatis). Since the universal is whatever can be a predicate of many,24 the quidditative concept, in principle, can be a predicate of different singular things.

Aquinas states that what is predicated of individuals is the essence absolutely considered.25 But since the content of a concept (direct universal) is merely an intelligible determination, an essence absolutely considered, how can it be related to singular things? Being neither single nor multiple, neither singular nor universal, how can the essence absolutely considered, conceptually expressed in a univocal way, be attributed to numerically distinct beings? The statements Peter is a man and John is a man are true in principle. But it is not the singular essence of Peter that is attributed to Peter, since if this was the case, it could not be attributed to John. It is the essence absolutely considered that is in a univocal way attributed to Peter and John and that, thanks to this attribution, is considered to be instantiated in Peter and John. But how can it be attributed to numerically distinct beings without being considered universal, given that the universal is defined as that which can be said of many? But if it is universal, how can it 'exist' individualized in different singular individuals?26

Indeed, in a simple affirmative predication, what is attributed to the thing mentioned by the subject (the essence absolutely considered) must be distinguished from the conditions that enable the attribution (the fact that the essence absolutely considered has a universal mode of existence in the intellect).27 By existing in the intellect in a universal mode, the essence absolutely considered can be attributed to many numerically different individuals. The predicate 'man' in the predications Peter is a man and John is a man has a univocal meaning, since what is being attributed to numerically different beings (Peter and John) is the essence absolutely considered, which by abstracting the individual characteristics of Peter and John can possess the same relation of uniform likeness with Peter and John as individuals who, in reality, have a numerically distinct essence. Taken in itself, independent of its occurrence in the predication, the concept man does not signify the individual essence of either John or Peter. Its meaning is independent of the mode through which its content exists in the individual or in the mind. Not only universality – which enables the essence to be predicable to many individuals –, but also the singular existence in any particular individual are accidental to the essence as absolutely considered.

But how can the essence absolutely considered, which does not signify any individual essence, be the likeness of the essence of a singular being? How can a universal concept, which expresses an essence absolutely considered, represent a singular thing?

These questions have a direct bearing on Aquinas's linguistic analysis of predicative statements. For both epistemological and ontological reasons, Aquinas argues that we can only understand singular things, composed of matter and form, through concepts. Singular material things are not directly intelligible by the intellect because matter, which is their principle of individuation, is only potentially intelligible. The intellect only knows singular things indirectly through reflexion.28 It is necessary to abstract (without precision), – that is, to leave out – the individualizing conditions of singular material things for them to become intelligible in act. Because of this, the human intellect forms concepts, which express natures absolutely considered. Now, as I have already pointed out, in a predicative sentence the logical subject has the function of mentioning things. The expressions that perform the function of a logical subject in a predicative sentence are general terms, which signify concepts, since if they did not signify concepts, singular things in principle would not be understood and could not therefore be mentioned. A question arises, then: How can general terms, which signify universal concepts, mention singular things if concepts express essences absolutely considered, and hence quiddities without any relation to singular things? How can general terms signifying concepts mention singular things?

Aquinas's semantics classifies29 the simple predicative sentences (single and simple,30 in his terminology) in terms of their quality (affirmative/negative sentences) and their quantity (universal/particular/singular/indefinite sentences). A predicative sentence is universal when its subject concept is taken universally. Note that the concept is always universal. Quantifying it means taking the universal (concept) universally, particularly or singularly. A predicative sentence is particular (singular) when its subject concept is taken particularly (singularly). A predicative sentence is indefinite when its subject concept is not preceded by the syncategorematic terms 'all,' 'some', or 'this.' Then, the indefinite sentence is assimilated with a particular sentence. Hence, quantifying a sentence means quantifying the subject concept31 of the predicative sentence. But what is the logical subject of these quantified sentences if their subject concept is always a universal that can be taken universally, particularly or singularly?

From the Thomistic point of view, it can be claimed that logical subjects (those dealt with by simple predicative sentences)32 are always singular individuals, considered either as singular or as whatever is common in various singular individuals. Indeed, in his commentary to Aristotle's De interpretatione, Aquinas explains that one can consider in a singular thing what it is proper to it (what, therefore, belongs only to this singular thing) and also what is common to various other singular things. One can attribute to Socrates what belongs only to Socrates, just as one can also attribute to Socrates what is common to Socrates, to Plato and to other individuals.

Commenting on Aristotle, Aquinas explains the meaning of quantifiers in the following way. One can predicate something of the universal in two ways: a) as possessing a separate existence from singular things (an existence in the mind, for example) or b) as being in singular things. This would explain the difference between the following types of statement: man is a species and man is mortal. Case 'a' was analyzed exhaustively by the medieval theory of supposition, which differentiated various types of supposition. Among other things, this allowed statements of the kind man has three letters to be distinguished from statements of the kind man is a species. But, for Aquinas, quantification applies only to case 'b.' As I have already mentioned, the universal (concept) can be taken universally, particularly or singularly. What does it mean, for example, to take the universal universally? Aquinas explains:

Quandoque enim attribuitur aliquid uniuersali ratione ipsius nature uniuersalis, et ideo hoc dicitur predicari de eo uniuersaliter, quia scilicet conuenit ei secundum totam multitudinem in qua inuenitur; et ad hoc designandum in affirmatiuis predicationibus adinuenta est hec dictio 'omnis' que designat quod predicatum attribuatur uniuersali subiecto quantum ad totum id quod sub eo continetur; [..] 33

The universal concept (obtained by abstraction without precision), which is a subject of a predicative sentence, may signify a unique thing. In this case, the universal concept is taken singularly. Hence sentences of the form: This man (Socrates say) is X. But the universal concept may also signify what is common to all or some singular things. Hence sentences of the form: Every man (that is, Socrates and Plato and Aristotle and...) is X and Some man (Socrates or Plato or...) is X. In these cases, the universal concept is taken universally or particularly to signify a property common to different individuals. From this it follows that the logical subject is not the common property expressed by the concept, but that it is the individuals who hold in common the property signified by the concept.

Explaining the function of quantifiers in this way presumes that universal concepts (obtained by abstraction without precision) taken universally, particularly or singularly have a relation to singular things. Thus, the universal concept would signify singular things under a common property. How to explain this thesis, given that concepts have as their content essences absolutely considered?

The first operation of the intellect involves a relation with the sensible due to the fact that quiddity has been abstracted from the phantasm. But it also involves another relation with the sensible as a result of the operation that Aquinas calls a 'turn toward phantasm'.34 The explanation of the need for this operation is complex, since it involves both epistemological and ontological considerations. As I mentioned earlier, it is a Thomistic thesis that the intellect directly apprehends only the universal, and only indirectly apprehends the singular, since the latter can be grasped solely by the senses.35 Thus, if the proper object, of human knowledge was only the quiddity expressed conceptually, only the forms independent of matter, represented by abstract intelligible determinations, could be known by the human intellect. But according to the hylemorphic thesis, it pertains to the nature of these forms to exist in an individual composed of matter and form. It pertains to the nature of the stone to exist in this stone.36 Therefore, if the human intellect has the power to know, the proper object of its knowledge cannot be the quiddity that is expressed conceptually, but must be the quiddity in material things.37 For Aquinas, the abstract quiddity is always undetermined; what is determined is always the concrete singular thing.38 And this can only be represented or known by the turn towards phantasm.

It is, therefore, necessary 'to concretize' the quiddity or to produce – in Maréchal's expression – a concretive synthesis, that is, to correlate the abstract quiddity with the phantasm that, taken in itself, comprises a subjective representation of a singular content. This concretive synthesis renders intelligible the phantasm and shows how the universal concept can be considered an intelligible likeness of singular objects.

However, the concretive synthesis is still an operation pertaining to the first operation of the intellect. It is not a judicative synthesis of the predicate and the subject, but merely a condition enabling a predication to be made. Indeed, simple affirmative predicative sentences take the form S is P, where 'S' stands for a general term, quantified or otherwise. The subjects of predicative sentences are always general terms signifying universal concepts. The concept-phantasm relation is a condition for a concept to be able to mention or represent singular objects in a judgment by composition and thus be able to perform the function of a subject of a predicative sentence.

Thus the concretive synthesis helps to explain that sensible representations of singular objects are contained under a common property expressed conceptually. This makes a whole series of Thomistic definitions or theses plausible: the definition of the universal as what can be said of many; the thesis that the logical subject of simple predicative sentences with general quantified terms is singular things, and so forth.


3. Predication, composition and division

The first operation of the intellect concerns the conceptual representation; the second operation, the knowledge of objects. This second operation of the intellect is usually called the intellectual act of judgment by interpreters of Aquinas. However, as highlighted earlier, in a certain way the senses also judge.39 Indeed, Aquinas calls this second operation composition and division. Hence it is useful to distinguish judgment, which can be an act of the senses or of the intellect, from the properly intellectual act of judging by composition and division that characterizes the second operation. The human intellect knows by judgment that composes and divides.40

The composition involved in the second operation of the intellect is not, though, a mere union of concepts like the operation uniting two distinct concepts – for example, the operation expressed by the complex concept a fair man.

Composing and dividing mean synthesizing concepts through predication. Aquinas provides a precise explanation of the meaning of a conceptual composition by predication: "[...] nam in omni propositione aliquam formam significatam per praedicatum, vel applicat alicui rei significatae per subiectum, vel removeat ab ea."41 In an affirmative predicative sentence, the subject concept expresses a property that can include diverse things (objects) that hold this property in common. The predicate concept expresses a property that applies to things mentioned by the subject concept. Thanks to the subject concept, the predicate concept (which signifies a form42) is related to the things mentioned by the subject of the predicative sentence. Hence the predicative sentence evidently cannot be analyzed as if it were a relation between two things signified by the subject concept and the predicate concept. Instead, it is analyzed by Aquinas in a manner analogous to the relation between form and matter: the predicate signifies a form that determines intelligibly the thing signified by the subject, which thereby performs the function of matter in the hylemorphic composition, "[…] praedicata tenentur formaliter, et subiecta materialiter." 43

Predicative composition or division is characterized by the distinction between two functions, both performed by concepts: the subject concept mentions things (a determined thing, or some things, or all the things that share a property) while the predicate merely classifies or determines things intelligibly through the mediation of the subject concept. This explains the thesis of the Thomist logician Vincent Ferrer,44 who claimed that predicates do not suppose since they do not mention things directly. Only the subject concept in the predication can 'suppose'; predicates merely classify, through properties, the things mentioned by the subject concept.

What is the linguistic operation that signifies the operation of composition and division?

In his commentary to the Peryermeneias,45 Thomas Aquinas distinguishes what he calls perfect sentences (such as interrogative and imperative sentences), defined as sentences without a truth value, from perfect sentences with a truth value, which he calls statements. Hence, statements are sentences which have perfect sentences as their genus. What Aquinas calls perfect sentences are what we call predicative sentences. These are characterized by the application of a property to – or the exclusion of a property from – the thing signified by the subject. This determines what is being attributed to what is being mentioned. Hence, for example, in satisfying the conditions of a predication, an interrogative sentence is a predicative sentence, but not a statement, since questions are neither true nor false.

One consequence of this distinction is that although the predicate in predicative sentences is united with the subject by the copula, such sentences do not involve a description of the real, since they do not say or affirm that something is or is not the case. However, the synthesis of the predicate with the subject in the predication is realized through the verb to be. What is the meaning of this verb in predicative sentences? As well as its synthetic function, does it also have an existential function? Does it signify or consignify (to use Aquinas's expression) that something is the case? If so, do the predicative sentences have, in themselves, an apophantic function? Consequently, should they be assimilated with statements?

Along with the distinction between those perfect sentences with a truth value and those without, Aquinas introduces another distinction that applies to predicative sentences and, consequently, to statements. This concerns the difference between predicative sentences formed by two elements (noun/verb) or by three elements (a tertium adiacens sentence composed of a noun and complex predicate). This distinction elucidates the function played by the verb to be and differentiates the attributive function from the existential function of statements.

A tertium adiacens sentence is composed of a subject term and a predicate formed by two words: the verb to be and another expression (a noun term that denotes a concept). The form of this statement is S is P, where is P is a complex expression, formed by two terms, one of them being a noun.

[...] 'est' predicatur ut adiacens principali predicato, et dicitur esse tercium non quia sit tercium predicatum, set quia est tercia dictio posita in enunciatione, que simul cum nomine predicato facit unum predicatum, ut sic enunciatio diuidatur in duas partes , non in tres46.

Thus, the verb to be, when it executes the function of the copula, has the meaning of the verb inesse: the form signified by the predicate is (or is not) in the thing signified by the subject.47

A sentence can also be formed by two terms: a subject term and a simple term, which must be a verb, since there are no predicative sentences without verbs.48 If the verb of the sentence formed by two terms is the verb to be, the predicative sentence signifies that whatever is signified by the subject term actually exists. Note that this 'existential' predication can be used in a question or a prayer and can, therefore, be used without an apophantic function.

When applied to statements, the distinction between a tertium adiacens sentence and that formed by a name and a simple predicate (constituted by a single word) allows the existential function to be differentiated linguistically from the attributive function. A statement of the form S is is an existential statement and signifies that the object mentioned by the subject exists: "[...] ut cum dicitur 'Sortes est', per quod nichil aliud intendimus significare quam quod Sortes sit in rerum natura; [...]"49 But in a tertium adiacens statement (taking the form S is P), the effective existence of whatever is expressed by the subject term is not directly affirmed; instead, it states that the thing indicated by the subject satisfies the property signified by the predicate. Thus, in a tertium adiacens statement, the existence of the thing mentioned is not affirmed, though it may be supposed. Obviously, supposing the existence of a thing is not the same as affirming its existence.

[...] quandoque uero non predicatur per se, quasi principale predicatum, set quasi coniunctum principali predicato ad connectendum ipsum subiecto, sicut cum dicitur "Sortes est albus":  non enim est intentio loquentis ut asserat Sortem esse in rerum natura, set ut attribuat ei albedinem mediante hoc verbo est; [...].50

Hence Aquinas seems to reject the analysis of the predicative statement of the form S is P as meaning S exists as P,51 insofar as existence is not posited in the tertium adiacens statement but merely supposed.


4. Statements and judgment by composition and division

Thomas Aquinas affirms that, among the predicative sentences, only statements have a truth value. From this it follows that only complex terms of the second operation of the intellect, that is, judgments by composition and division, can have a truth value. Non-complex terms – concepts, in other words – are neither true nor false. However, some of Aquinas's texts contradict this thesis where they state that the cognoscitive faculties cannot be wrong and are always true in relation to their proper objects. There is, therefore, truth in the operations of the senses and in the first operation of the intellect.52 Now, as the proper object of the intellective faculty is the quiddity of material things, it is only accidentally that the intellect is mistaken in the definitions that make explicit the characteristics of quiddities.

There would seem to be an inconsistency in Thomas Aquinas's claims that, on one hand, only the complex terms produced by composition or division are true or false, while, on the other hand, the senses and the intellect are true in relation to their proper objects. Therefore, what results from the operations that precede the intellectual act of judgment by composition and division would be true. How, then, to reconcile the Thomistic claims that truth is only applicable to judgments by composition and division, and that, on the other hand, the term of some prejudicative operations can be considered true?

Answering this question takes us to Aquinas's analysis of the notion of truth.

Thomas Aquinas analyzes truth under three aspects:53 1) the foundation of truth (being [ens]), which is what makes a statement true, 2) the formal definition of truth, which is the intellect's agreement with the thing, and 3) the consequence of truth, which is knowledge.

The first two aspects are not problematic when formulated in a realist context. But what is the precise meaning of the third aspect of the analysis of truth: "[...] sic ergo entitas rei praecedit rationem veritatis sed cognitio est quidam veritatis effectus."?54

Aquinas seems to have been led to formulate this thesis on account of the following arguments: the sensible species55 and, in particular, the sensible species of the imagination or phantasm, 56 are intentional likenesses of the sensed things. Quidditive concepts are also likenesses of properties of things. Sensible faculties, for their part, can only be false accidentally with regard to their proper objects.57 This also applies to concepts insofar as the quiddity of material things is the proper object of the human intellect and concepts signify quiddities.58 But, Aquinas argues, while the proper objects of the senses and quiddities, expressed by concepts, can be considered true, the faculties that apprehend these objects do not know or state the truth.59 Only the intellect in the judgment by composition and division can know its agreement with the thing known, that is, only in judgment is truth known.60 Why?

The acts of the cognoscitive faculties involve reflexion,61 which is awareness (cognitio) of the execution of an act,62 that is, awareness of the act executed. As an act of the intellect, the act of judging involves reflexion. But the reflexion involved in this act is not just the awareness that accompanies the execution of an act, but the awareness of the relation (proportio) of the attribution of the intentional form signified by the predicate with the thing signified by the subject; it comprises, therefore, awareness of the relation of the intentional act (judgment) with the thing. In this case, awareness is not something superimposed on the act, nor something that only accompanies the execution of the act, but something that constitutes the act itself, since without reflection there would be no signification of the real; in other words, there would be no relation of the representational act with the thing itself intended. Thus, the act of judging depends on an awareness of the act because it is constituted by it. But why?

The principle of the act of judging is the intellect. Hence, awareness of the act of judging involves awareness of this principle, that is, awareness of the presence of the intellect in the act of judging.63 But awareness of the presence of this principle involves awareness of the function of the intellect. Aquinas expresses the awareness of this 'function' as awareness of the 'nature' of the intellect. However, this does not comprise the quidditative awareness of the essence of the intellect insofar as the intellect is an immaterial faculty, independent of the body, which has the human soul as its subject. Were this otherwise, only metaphysical philosophers would be able to predicate. In this case, we are dealing with the awareness that the intellect's nature is that of intending things or "that of agreeing with things:" […] intellectus, in cuius natura est ut rebus conformetur."64 Hence, the intellect is a faculty characterized by an immanent dynamism, one of intending things.65

According to the text of De veritate, therefore, the attribution of a property, expressed by the predicate, to a thing, mentioned by the subject,66 involves the awareness (cognitio) of the relation (proportio) of the act to the thing. The awareness of this relation is conditioned by the awareness that the function of the intellect – which is the principle of the act of attribution – is that of agreeing with things.67

Having an intelligible species, as happens, for example, when one apprehends a quiddity, may involve awareness insofar as the act of forming a quidditative concept is an intellectual act. However, the awareness of this act does not involve awareness of the relation of attribution between the form and the thing, since it is this relation that characterizes the act of judging and distinguishes it from the act of forming concepts.

Since awareness of the relation is absent, it cannot involve the awareness of the dynamism of the intellect, which is that of agreeing with things. It follows that the act of producing concepts does not involve a complete reflexion.

We have already seen that 'predicative sentences' signify the composition and division presupposed by every intellectual judgment; 'statements' signify judgments by composition and division, which are characterized by their possession of truth value. But if 'to predicate' signifies to compose or divide, and if the notion of judgment by composition and division is not identified with the notion of predication, it is reasonable to ask whether reflexion is a necessary condition for the realization of the predicative act or for the realization of the intellectual act of judgment by composition and division.

The text of De veritate I, 9 discusses the knowledge of truth, that is, knowledge of the agreement of the judgment with the thing. Here Aquinas analyses one of the conditions of the knowledge of truth. His thesis is that only judgment by composition and division (and not mere predication) is capable of 'saying the truth.' But if so, mere predication (or composition and division) cannot satisfy the condition determining that only a judgment by composition and division can be true or false. If this were not the case, any predicative sentence (interrogative, imperative and so on) would also be true or false.

The notion of reflection expounded in De Veritate is further developed in the Commentary on the Metaphysics.68 In this text, Aquinas reiterates that only the second operation of the intellect contains truth or falsity, since only in this operation does the intellect not only possess the likeness of the conceived thing, but also reflects on it, knowing it as a likeness of the thing and attributing this intentional likeness to the thing itself.

This attribution of intentional likeness to the extra-mental thing, which has the complete reflexion as a condition, is effected through the act of affirming or negating. This is what Aquinas writes in his Commentary on the Metaphysics:69 judgments (complex terms in opposition to simple conceptual terms) possess truth or falsity through affirmation and negation. But what is the meaning of the expressions affirmation and negation?

Commenting on a text from Aristotle's De interpretatione70 and a number of its medieval interpretations, Aquinas adopts the analysis proposed by Ammonius and states that "[...] affirmatio est enunciatio alicuius de aliquo, per quod significatur esse, et negatio enunciatio alicuius ab aliquo, quod significat non esse."71

What does this text mean?

Usually, a predication is called affirmative when the copula's function is to compose the predicate with the subject. In order to perform this function, the verb to be is used. Predication is called negative when the copula's function is to divide or separate the predicate from the subject. Obviously this function is performed when the copula is preceded by the operator 'not.' But the affirmation to which Aquinas's text refers is not a predicative affirmation or negation; it is an apophantic affirmation or negation, since its function is not only to compose or separate the predicate from the subject, but, through this composition or division, to posit the composition or separation as real; hence, to affirm (or negate) that something is or is not the case.

Apophantic affirmations and negations are operators that execute their functions through predicative affirmations or negations, transforming the affirmative predication into an affirmative statement or transforming a negative predication into a negative statement. Stating an affirmative predication means considering that the property expressed by the predicate is effectively in the thing mentioned by the subject concept. Stating a negative predication means excluding a property (expressed by the predicate-concept) from something effectively real, or to consider non-existent the thing mentioned by the subject concept. For this reason, affirming or negating a predication signifies being or non-being. But the predication does not by itself signify being or non-being through composition or division; rather, the statement does this through the apophantic affirmation or negation. Thus, affirmation and negation are apophantic and predicative operators, since, on one hand, they transform a predication into a statment, positing the predication as real (objective); on the other hand, they are also predicative operators that express either the union or the separation of the predicate and the subject.

Thus, the predicative affirmation or negation possesses its own way of correlating what is signified by the predicative sentence with reality. For example, an affirmative statement is true if it states that it is what it is; a negative statement is false if it states that it is not what it is; an affirmative statement is false if it states that it is what it is not; and a negative statement is true if it states that it is not what it is not.

Having established the truth conditions of affirmative and negative statements, not only do their apophantic and predicative functions become evident, but also the contradictory opposition between them.

But does the claim that a true negative statement signifies that it is not what it is not compromise Thomas Aquinas's ontology with so-called negative facts? Is what is not, non-being, responsible for making the negative statement true?

The true negative statement does not signify that what was separated by the predication corresponds to non-being, as if non-being were a reality just like being. Rather, it signifies either that the composition of the property (expressed by the predicate) with the thing (mentioned by the subject) is not found in reality, or that the thing itself mentioned by the subject does not exist. For this reason, thanks to negation, one can "say non-being" without implicating an ontology of negative facts.


4. Conclusion

Past and present interpreters of Aquinas have frequently disputed the role played by the notions of essence (or quiddity), being (ens), being (esse) and existence in Thomistic metaphysics. These notions have appeared in my exposition of the Thomistic theory of judgement as analysing the notions of concept, judgment by composition and division, and existential statement. The different functions performed by these notions in the theory of judgment are indications of certain theses of Thomistic metaphysics, which affirm, for example, the real distinction or composition between being and essence in the finite being (ens).

Concepts connected to the phantasms are intentional similitudes of singular things. They universally express quiddities that, taken in themselves, are neither singular nor universal, although they exist in a singular way in material things and in a universal/abstract way in the intellect.72

The formation of concepts is one stage in the production of judgments. Concepts perform the role of subject and predicate in the judgment, enabling "something to be said of something." But the predication is not yet an instantiation of quiddities in a real singular subject. Aquinas writes in De ente et essentia:73 "Omnis autem essentia vel quiditas potest intelligi sine hoc quod aliquid intelligatur de esse suo: possum enim intlligere quid est homo vel fenix et tamen ignorare an esse habeat in rerum natura; ergo patet quod esse est aliud ab essentia vel quiditate." This argument seems to be based on the difference between concept and judgment and demonstrates the logical distinction (which is not yet a real distinction) between essence and being.

All affirmative or negative statements, whether true or false, signify being or non-being, since they correlate quiddity – expressed conceptually – with the real. In the theory of judgment, the notion of being does not yet have its metaphysical meaning of an act of being (actus essendi) or the "actuality of all acts and because of this, perfection of all perfections."74 In judgments, being signifies reality taken in itself, in opposition to the intentional or representative being (ens).

But is the notion of being (esse) in the theory of judgment not identified here with the notion of being (ens), that which is (quod habet esse)? Without analyzing this difficult question, the subject of numerous books and articles, I would simply point out that, from the viewpoint of judgment, what the concept apprehends must be distinguished from what the judgment by composition and division signifies. Everything that is apprehended conceptually by the intellect involves the notion of being (ens).75 Being (esse), in the sense indicated above, is not expressed quidditatively: rather, it is 'apprehended' or signified by judgment,76 whose function is to 'posit' what it signifies or represents as real (possible or actual).

Some statements are existential (such as those of the form S is), affirming or negating that something indeed exists. Other true statements suppose the existence of something without, though, affirming it (such as the affirmative tertium adiacens statements of the form S is P); others statements are true and neither affirm or suppose existence (such as some negative tertium adiacens statements). Affirmative or negative statements signify the notion of being or non-being; existential statements affirm or negate the factual actuality of whatever is mentioned by the subject concept. Hence, producing a statement or signifying being through the production of an affirmative statement is not equivalent to affirming that something exists. From the viewpoint of the theory of judgment, being does not have the same meaning as existence.

The distinctions between being (esse), being (ens), essence and existence involved in the analysis of Thomist judgment are suggestive and their explanation would seem to demand a metaphysical analysis. Pursuing, then, a certain philosophical tradition, the Thomistic theory of judgment can be seen as the ante-room or 'starting point' of metaphysics.



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1 On this topic, see in Portuguese the excellent articles of H. VAZ: 'Itinerário da Ontologia Clássica' (VAZ 1968, p. 67-91) and 'Tomás de Aquino: Pensar a Metafísica na Aurora de um Novo Século'  (VAZ 1996, p. 159-207).
2 See 'transcendental Thomism,' whose key work is MARÉCHAL 1949, its most prominent later exponents being K. Rahner, J. de Finance and A. Marc.
3 See 'existential Thomism,' whose key work is the book by GILSON 1948. An English version of this work was published under the title Being and some philosophers. The book's second edition contains an important Appendix with a critique of Gilson's interpretation by L. M. Régis, and a reply by Gilson himself. J. Maritain, L. Geiger, J. Owens and others have also contributed in different ways to this line of interpretation. See too the penetrating critique of 'existential Thomism' by McINERNY 1986, p. 173-228. Wippel, although he cannot be considered an 'existential Thomist,' agrees with many of the theses of this school. See, for instance, his book The metaphysical thought of Thomas Aquinas, p. 21-62.
4 See ANSCOMBE & GEACH 1961. Geach published numerous articles on Aquinas's philosophy. See in particular GEACH 1969, p. 42-64.
5 In this article, I shall not analyze the question of the intellection of the 'first principles' and their function in the constitution of demonstrative science. Indeed, the first principles are the "regulatory and constitutive norms" of the intellectual act. (See, for example, the function of the principle of contradiction in quidditative apprehension and in the judgment of composition and division). But examining this question involves analyzing the problem of the 'enlightenment' of the human intellect by the divine intellect or that of the participation of the human intellect in the divine intellect. The study of these themes transcends the objective of this article insofar as it demands a detailed consideration of the quidditative nature of the human intellect and the intellect in general.
6 GARCEAU 1968, p. 101-152 and 265-278.
7 AQUINAS 1989. (See too the French translation by B. Couillaud & M. Couillaud:  Commentaire du traité de l'interprétation d' Aristote.)
9 De interpretatione, op. cit., 16b 8.
10 Idem, op. cit., 16a 19-20 and 16a 32- 16b 7.
11 See Geach's analysis of the notions of subject and predicate, which are based on Aquinas's commentary to De interpretatione: GEACH 1968, p. 22-44.
12 Peryermenias, op. cit., I, chap. 5, p. 30-31.
13 "[...] inde est quod, cum volumus significare quamcunque formam vel actum actualiter inesse alicui subiecto, significamus illud per hoc verbum 'est,' simpliciter quidem secundum presens tempus, secundum quid autem secundum alia tempora [...]" (Peryermenias, op. cit., I, chap. 5, p. 31).
In this article, the texts in Latin are cited in accordance with the orthography adopted by the edition from which the text was extracted. It should be noted that different editions of Thomas Aquinas's work use different orthographies and conventions for the same Latin words.
14 Geach states that Thomas Aquinas distinguishes two types of 'existential' statements: those of the form "there is a P" where P goes proxy for a general term, and those of the form S exists. On this topic, see GEACH, Three philosophers, p. 88-91. Also see WEIDEMANN 2002, p. 77-95.
15 Summa contra gentiles, II, 54:"[...]  quæ a quibusdam dicitur ex quod est et esse; vel ex quod est et quo est."
16 Peryermenias, op. cit., I, chap. 2, p. 11.
17 Librum boethii de trinitate, q. 6, a. 2.
18 See, for example, the comments on De trinitate (op. cit., q. 5, a. 3), on Peryermenias (op. cit., I, 1, p. 5) and on Metaphysics (in Libros metaphysicorum, 1, VI, chap. 4).
19 De veritate, q. 1, a. 9. (See the French translation, bilingual edition, by BROUWER & PEETERS 2002.)
20 Quiddity expresses the formal definition of essence. See: Summa theologiae (ST) I, 29, a. 3. I use the term to mean simply any intelligible property.
21 The operation of abstraction was analyzed by Aquinas thematically in the texts: Librum boethii de trinitate (op. cit., q. 5, a. 3),  De ente et essentia, chap. 2 and Summa theologiae, I, q. 85, a. 1 and 2.
22 Note that the Thomistic theory of abstraction was modified, at least terminologically, by Cajetano in his Commentary on De ente et essentia and the Summa. Abstraction was classified here as formal abstraction with its three levels (abstraction of sensible matter, intelligible matter and matter) and total abstraction. These distinctions of levels of abstraction (rather than modes of abstraction) do not wholly express Aquinas's conception of abstraction and, in any case, indirectly place in question the function of judgment expounded in the course of this article.
23 De ente, op. cit., chap. 2, p. 91-95. On the notion of a nature absolutely considered, see: a) CAJETANO 1964, p. 155-164; b) EDWARDS 2002, p. 97-115; c) OWENS 1980, p. 52-96; d) TONQUÉDEC 1961, p. 155-163.
24 De interpretatione, op. cit., 17a 39-40; ST, I, 85, a. 2, ad 2; Libros metaphysicorum, 1, VII, chap. 13.
25 De ente, op. cit., chap. 3, p. 92: "Ergo patet quod natura hominis absolute considerata abstrahit a quolibet esse, ita tamen quod non fiat praecisio alicuius eorum. Et haec natura sic considerata est quae praedicatur de individuis omnibus."
26 On this problem, see: De ente, op. cit., p. 91-94 and the book by LIBERA 1996, p. 281-282.
27 CAJETANO 1964, p. 156.
28 Summa theologiae, I, 86, a. 1.
29 Peryermenias, op. cit., I, chap. 10, p. 51-52.
30 Idem, I, chap. 8.
31 Some medieval logicians accepted that the predicate can also be 'quantified:' for them, the predicate of an affirmative predicative sentence is taken particularly; the predicate of a negative predicative sentence is taken universally.
32 Obviously, this analysis applies to predicative sentences whose general terms signify the direct universal.
33 Peryermenias, op. cit., I, chap. 10, p. 52.
34 Summa theologiae, I, 84, a. 7.
35 Summa theologiae, I, 86, a. 1. Note that the intellect apprehends the universal directly but not immediately, since the universal is obtained by the operation of abstraction.
36 Summa theologiae, I, 84, a. 7, c :"[...] sicut de ratione naturae lapidis est quod sit in hoc lapide, et de ratione naturae equi quod sit in hoc equo, et sic de aliis."
37 Summa theologiae, I, 85, a. 8 ; I, 88, a. 2 and 3.
38 See FOREST 1956, p. 72-97.
39 See, for example,, De veritate, op. cit., I, 9 and Summa theologiae, I, 17, a. 2.
40 Summa theologiae, I, 16, a. 2, c: "[...] sed quando iudicat rem ita se habere sicut est forma quam de re apprehendit, tunc primo cognoscit et dicit verum. Et hoc facit componendo et dividendo: nam in omni propositione aliquam formam significatam per praedicatum, vel applicat alicui rei significatae per subiectum, vel removeat ab ea."
41 Idem.
42 See ANSCOMBE & GEACH, 1961, p. 75-81. According to these authors, what Aquinas calls form can be expressed as a logical predicate... is P or (in the case of a form occupying the subject position of the predication) it may be signified by the expression P of..., demanding, therefore, a complement of a (proper) object name.
43 Summa theologiae, I, 13, a. 12, c. and Peryermenias, op. cit., I, chap. 8, p. 42: "[...] nam predicatum comparatur ad subiectum ut forma ad materiam, [...]".
44 FERRER, 1977, p. 93.
45 Peryermeneias, op. cit., I, chap. 7.
46 Peryermenias, op. cit., II, chap. 2, p. 88.
47 Libros metaphysicorum, l, VI, chap. 4, n. 1223: "Dicitur autem hic affirmatio compositio, quia significat praedicatum inesse subiecto. Negatio vero dicitur hic divisio, quia significat praedicatum a subiecto removeri."
48 Peryermenias, op. cit., I, chap. 8, p. 40-41.
49 Idem, II, chap. 2, p. 88.
50 Ibidem, p. 88.
51 See BÄCK 2000, p. 98-131.
52 Summa theologiae, I, 17, a. 2-3; I, 85, a. 6 and Peryermenias, op. cit., I, chap. 3, p. 16.
53 De veritate, op. cit., I, 1.
54 Idem. See too: Summa theologiae, I, 16, a. 2, c.
55 Summa theologiae, I, 17, a. 2; I, 78, a. 4, ad 2.
56 Summa theologiae, I, 79, a. 4, ad 4.
57 De veritate, op. cit., I, a. 11; Summa theologiae, I, 17, a. 2.
58 Summa theologiae, I, 17, a. 3; I, 85, a. 6.
59 Summa theologiae, I, 16, a. 2, c : "Et ideo bene invenitur quod sensus est verus de aliqua re, vel intellectus cognoscendo quod quid est: sed non quod cognoscat aut dicam verum". Summa theologiae I, a. 3, c; Libros metaphysicorum, l, VI, chap. 4 and Peryermenias, op. cit., I, chap. 3, p. 16-17.
60 Summa theologiae, I, 16, a. 2, c: "Unde  conformitatem istam cognoscere, est cognoscere veritatem."
61 De veritate, op. cit., q. 1, a. 9. See the classic commentary on this article by BOYER 1924, p. 219-224 and the books by DE FINANCE 1946, p. 23-46 and PUTALAZZ 1991, p. 150-202.
62 De veritate, op. cit., I, 9:"Sensus autem [...] cognoscit se sentire."
63 Summa Theologiae, I, 87, a. 1, c.
64 De veritate, I, 9.
65 See PUTALLAZ 1991, p. 195.
66 Summa de Theologiae, I, a. 16, a. 2, c.
67 The reflexion (awareness or cognition) that constitutes the act of judging is called complete reflexion, since there is a complete return of the intellect onto itself.
68 Libros metaphysicorum, l, VI, chap. 4: "Intellectus autem habet apud se similitudinem rei intellectae, secundum quod rationes incomplexorum concipit; non tamen propter hoc ipsam similitudinem diiudicat, sed solum cum componit vel dividit. Cum enim intellectus concipit hoc quod est animal rationale mortale, apud se similitudinem hominis habet; sed non propter hoc cognoscit se hanc similitudinem habere, quia non iudicat hominem esse animal rationale et mortale: et ideo in hac sola secunda operatione intellectus est veritas et falsitas, secundum quam non solum intellectus habet similitudinem rei intellectae, sed etiam super ipsam similitudinem reflectitur, cognoscendo et diiudicando ipsam."
69 Libros metaphysicorum, 1, VI, chap. 4: "Voces enim incomplexae neque verum neque falsum significant; sed voces complexae, per affirmationem aut negationem veritatem aut falsitatem habent. Dicitur autem hic affirmatio compositio, quia significat praedicatum inesse subiecto. Negatio vero dicitur hic divisio, quia significat praedicatum a subiecto removeri."
70 De interpretatione, op. cit., 17ª 23-17ª 25.
71  Peryermenias, op. cit., I, chap. 8, p. 45.
72 Summa theologiae, I, 85, ad 2 : "Ipsa igitur natura cui accidit vel intelligi vel abstrahi, vel intentio universalitatis non est nisi in singularibus; sed hoc ipsum quod est intelligi vel abstrahi, vel intentio universalitatis, est in intellectu."
73 De ente et essentia, Op. cit., p. 102.
74 De potentia, q. 7, a. 2, ad 9 : "[...] quod dico esse est actualitas omnium actuum, et propter hoc est perfectio omnium perfectionum."
75 See, for example, De veritate, op. cit., q. 1, a.1 ; De ente, op. cit., Prologue;  Summa theologiae, I, q. 5, a. 2.
76 De trinitate, op. cit., q. 5, a. 3.