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In the preceding chapter I enumerated and discussed what Aristotle calls the Categories. We shall now proceed to the work which stands second in the aggregate called the Organon the treatise De Interpretatione.

We have already seen that the Aristotelian Ontology distinguishes one group of varieties of Ens (or different meanings of the term Ens) as corresponding to the diversity of the ten Categories; while recognizing also another variety of Ens as Truth, with its antithesis Non-Ens as Falsehood.1 The former group was dealt with in the preceding chapter; the latter will form the subject of the present chapter. In both, indeed, Ontology is looked at as implicated with Logic; that is, Ens is considered as distributed under significant names, fit to be coupled in propositions. This is the common basis both of the Categorić and of the treatise De Interpretatione. The whole classification of the Categories rests on the assumption of the proposition with its constituent parts, and on the different relation borne by each of the nine genera of predicates towards their common Subject. But in the Categorić no account was taken of the distinction between truth and falsehood, in the application of these predicates to the Subject. If we say of Sokrates, that he is fair, pug-nosed, brave, wise, &c., we shall predicate truly; if we say that he is black, high-nosed, cowardly, stupid, &c., we shall predicate falsely; but in each case our predicates will belong to the same Category that of Quale. Whether we describe him as he now is, standing, talking, in the market-place at Athens; or whether we describe him as he is not, sitting down, singing, in Egypt in both speeches, our predicates rank under the same Categories, Jacere, Agere, Ubi. No account is taken in the Categorić of the distinction between true and false application of predicates; we are only informed under what number of general heads all our predicates must be included, whether our propositions be true or false in each particular case.

1 See above in the preceding chapter, p. 60.

But this distinction between true and false, which remained unnoticed in the Categorić, comes into the foreground in the treatise De Interpretatione. The Proposition, or enunciative speech,2 is distinguished from other varieties of speech (interrogative, precative, imperative) by its communicating what is true or what is false. It is defined to be a complex significant speech, composed of two terms at least, each in itself significant, yet neither of them, separately taken, communicating truth or falsehood. The terms constituting the Proposition are declared to be a Noun in the nominative case, as Subject, and a Verb, as Predicate; this latter essentially connoting time, in order that the synthesis of the two may become the enunciation of a fact or quasi-fact, susceptible of being believed or disbelieved. All this mode of analysing a proposition, different from the analysis thereof given or implied in the Categorić, is conducted with a view to bring out prominently its function of imparting true or false information. The treatise called the Categorić is a theory of significant names subjicible and predicable, fit to serve as elements of propositions, but not yet looked at as put together into actual propositions; while in the treatise De Interpretatione they are assumed to be put together, and a theory is given of Propositions thus completed.

2 Aristot. De Interpret. p. 17, a. 1: λόγος ἀποφαντικός.

Words spoken are marks significant of mental impressions associated with them both by speaker and hearer; words written are symbols of those thus uttered. Both speech and writing differ in different nations, having no natural connection with the things signified. But these last, the affections or modifications of the mind, and the facts or objects of which they are representations or likenesses, are the same to all. Words are marks primarily and directly of the first, secondarily and indirectly of the second.3 Aristotle thus recognizes these two aspects first, the subjective, next the objective, as belonging, both of them conjointly, to significant language, yet as logically distinguishable; the former looking to the proximate correlatum, the latter to the ultimate.

3 Ibid. p. 16, a. 3, seq. ὣν μέντοι ταῦτα σημεῖα πρώτως, ταὐτὰ πᾶσι παθήματα τῆς ψυχῆς, καὶ ὧν ταῦτα ὁμοιώματα, πράγματα ἤδη ταὐτά.

For this doctrine, that the mental affections of mankind, and the things or facts which they represent, are the same everywhere, though the marks whereby they are signified differ, Aristotle refers us to his treatise De Animâ, to which he says that it properly belongs.4 He thus recognizes the legitimate dependence of Logic on Psychology or Mental Philosophy.

4 Aristot. De Interpret. p. 16, a. 8: περὶ μὲν οὖν ταύτων εἴρηται ἐν τοῖς περὶ ψυχῆςˇ ἄλλης γὰρ πραγματείας. It was upon this reference, mainly, that Andronikus the Rhodian rested his opinion, that the treatise De Interpretatione was not the work of Aristotle. Andronikus contended that there was nothing in the De Animâ to justify the reference. But Ammonius in his Scholia (p. 97, Brand.) makes a sufficient reply to the objection of Andronikus. The third book De Animâ (pp. 430, 431) lays down the doctrine here alluded to. Compare Torstricks Commentary, p. 210.

That which is signified by words (either single or in combination) is some variety of these mental affections or of the facts which they represent. But the signification of a single Term is distinguished, in an important point, from the signification of that conjunction of terms which we call a Proposition. A noun, or a verb, belonging to the aggregate called a language, is associated with one and the same phantasm5 or notion, without any conscious act of conjunction or disjunction, in the minds of speakers and hearers: when pronounced, it arrests for a certain time the flow of associated ideas, and determines the mind to dwell upon that particular group which is called its meaning.6 But neither the noun nor the verb, singly taken, does more than this; neither one of them affirms, or denies, or communicates any information true or false. For this last purpose, we must conjoin the two together in a certain way, and make a Proposition. The signification of the Proposition is thus specifically distinct from that of either of its two component elements. It communicates what purports to be matter of fact, which may be either true or false; in other words, it implies in the speaker, and raises in the hearer, the state of belief or disbelief, which does not attach either to the noun or to the verb separately. Herein the Proposition is discriminated from other significant arrangements of words (precative, interrogative, which convey no truth or falsehood), as well as from its own component parts. Each of these parts, noun and verb, has a significance of its own; but these are the ultimate elements of speech, for the parts of the noun or of the verb have no significance at all. The Verb is distinguished from the Noun by connoting time, and also by always serving as predicate to some noun as subject.7

5 Ibid. p. 16, a. 13: τὰ μὲν οὖν ὀνόματα αὐτὰ καὶ τὰ ῥήματα ἔοικε τῷ ἄνευ διαιρέσεως καὶ συνθέσεως νοήματι, οἷον τὸ ἄνθρωπος καὶ τὸ λευκόν, ὅταν μὴ προστέθῃ τιˇ οὔτε γὰρ ψεῦδος οὔτε ἀληθές πω.

6 Ibid. p. 16, b. 19: αὐτὰ μὲν καθ ἑαυτὰ λεγόμενα τὰ ῥήματα ὀνόματά ἐστι καὶ σημαίνει τι (ἵστησι γὰρ ὁ λέγων τὴν διάνοιαν, καὶ ὁ ἀκούσας ἠρέμησεν) ἀλλ εἰ ἐστὶν ἢ μή, οὔπω σημαίνει, &c.

Compare Analyt. Poster. II. xix. pp. 99, 100, where the same doctrine occurs: the movement of association is stopped, and the mind is determined to dwell upon a certain idea; one among an aggregate of runaways being arrested in flight, another halts also, and so the rest in succession, until at length the Universal, or the sum total, is detained, or stands still as an object of attention. Also Aristot. Problem. p. 956, b. 39.

7 Aristot. De Interpr. p. 16, b. 2, seq.

Aristotle intimates his opinion, distinctly and even repeatedly, upon the main question debated by Plato in the Kratylus. He lays it down that all significant speech is significant by convention only, and not by nature or as a natural instrument.8 He tells us also that, in this treatise, he does not mean to treat of all significant speech, but only of that variety which is known as enunciative. This last, as declaring truth or falsehood, is the only part belonging to Logic as he conceives it; other modes of speech, the precative, imperative, interrogative, &c., belong more naturally to Rhetoric or Poetic.9 Enunciative speech may be either simple or complex; it may be one enunciation, declaring one predicate (either in one word or in several words) of one subject; or it may comprise several such.10 The conjunction of the predicate with the subject constitutes the variety of proposition called Affirmation; the disjunction of the same two is Negation or Denial.11 But such conjunction or disjunction, operated by the cogitative act, between two mental states, takes place under the condition that, wherever conjunction may be enunciated, there also disjunction may be enunciated, and vice versâ. Whatever may be affirmed, it is possible also to deny; whatever may be denied, it is possible also to affirm.12

8 Ibid. p. 16, a. 26; p. 17, a. 2.

9 Ibid. p. 17, a. 6: ὁ δὲ ἀποφαντικὸς τῆς νῦν θεωρίας. See the Scholion of Ammonius, pp. 95, 96, 108, a. 27. In the last passage, Ammonius refers to a passage in one of the lost works of Theophrastus, wherein that philosopher distinguished τὸν ἀποφαντικὸν λόγον from the other varieties of λόγος, by the difference of σχέσις: the ἀποφαντικὸς λόγος was πρὸς τὰ πράγματα, or objective; the others were πρὸς τοὺς ἀκροωμένους, i.e. varying with the different varieties of hearers, or subjective.

10 Ibid. p. 17, a. 25.

11 Ibid. p. 17, a. 25.

12 Ibid. p. 17, a. 30: ἅπαν ἂν ἐνδέχοιτο καὶ ὃ κατέφησέ τις ἀποφῆσαι, καὶ ὃ ἀπέφησέ τις καταφῆσαι.

To every affirmative proposition there is thus opposed a contradictory negative proposition; to every negative a contradictory affirmative. This pair of contradictory opposites may be called an Antiphasis; always assuming that the predicate and subject of the two shall be really the same, without equivocation of terms a proviso necessary to guard against troublesome puzzles started by Sophists.13 And we must also distinguish these propositions opposite as Contradictories, from propositions opposite as Contraries. For this, it has to be observed that there is a distinction among things (πράγματα) as universal or singular, according as they are, in their nature, predicable of a number or not: homo is an example of the first, and Kallias is an example of the second. When, now, we affirm a predicate universally, we must attach the mark of universality to the subject and not to the predicate; we must say, Every man is white, No man is white. We cannot attach the mark of universality to the predicate, and say, Every man is every animal; this would be untrue.14 An affirmation, then, is contradictorily opposed to a negation, when one indicates that the subject is universally taken, and the other, that the subject is taken not universally, e.g. Omnis homo est albus, Non omnis homo est albus; Nullus homo est albus, Est aliquis homo albus. The opposition is contrary, when the affirmation is universal, and the negation is also universal, i.e., when the subject is marked as universally taken in each: for example, Omnis homo est albus, Nullus homo est albus. Of these contrary opposites, both cannot be true, but both may be false. Contradictory opposites, on the other hand, while they cannot both be true, cannot both be false; one must be false and the other true. This holds also where the subject is a singular term, as Sokrates.15 If, however, an universal term appear as subject in the proposition indefinitely, that is, without any mark of universality whatever, e.g., Est albus homo, Non est albus homo, then the affirmative and negative are not necessarily either contrary or contradictory, though they may be so sometimes: there is no opposition, properly speaking, between them; both may alike be true. This last observation (says Aristotle) will seem strange, because many persons suppose that Non est homo albus is equivalent to Nullus homo est albus; but the meaning of the two is not the same, nor does the truth of the latter follow from that of the former,16 since homo in the former may be construed as not universally taken.

13 Ibid. p. 17, a. 33: καὶ ἔστω ἀντίφασις τοῦτο, κατάφασις καὶ ἀπόφασις αἱ ἀντικείμεναι.

It seems (as Ammonius observes, Schol. p. 112, a. 33) that ἀντίφασις in this sense was a technical term, introduced by Aristotle.