Logic, we have seen, studies our thought about things; and that cannot be studied without some consideration of the nature of things; but further, it cannot be carried on, nor yet studied, without the use of signs——generally written or spoken words, which make what we call language. The relations of thought to things on the one hand and words on the other are difficult and intricate; but we cannot without some regard to them profitably attack the subject of this chapter. The true unit of thought, the simplest complete act of thought, or piece of thinking, is the Judgment, or Proposition: between which where a distinction is intended, it is that the proposition is the expression in words of a judgment. The close connection of language with thought appears already here; for the utterance of the words, unless we were at the same time meaning with them, or judging, would not really be making a proposition; else the man who repeated the words of an unknown tongue would be ‘propounding.’ We may indeed understand a proposition without judging it, but only by imaginatively putting ourselves in the situation of a man who is actually expressing his judgment by it. We may perceive without judging, though our present perception may be possible only through past judgments; and here as elsewhere the history of how the individual mind has come to be able to do what it now does is elusive; but that belongs rather to Psychology. I may pass a man in the street, and only afterwards say to myself ‘That must have been so-and-so’; I may be walking along a railway line in the dark, and hear a sound, and then hear it again, and for the first time think ‘That is the noise of a train approaching.’ I perceived the man, or heard the sound, the first time; I judged about them after; and when I judged (we shall return to this) I distinguished in the ‘subject’ I judged about a character which I ‘predicated’ of it. In judging then I always distinguish a particular element, the predicate, in the being of a subject which I could not think of unless I recognized in it some other than the predicated character. Hence a definition is not properly a judgment, as Aristotle saw (v. Met, Θ. x. 1051b17 sq.). For when I define anything——e.g., a triangle, and say that it is a three-sided rectilinear figure——I have not before me a subject already distinguished by some other character than what I predicate. Even here however I distinguish elements in an unity which they constitute; and hence the definition can be expressed in a proposition. For I give a name to this unity as an unity, and also to the elements distinguished in it. There are some objects of thought which have names, and by the help of instances we come to know them, but because they are simple, or because they are unique in nature, what they are cannot be expressed in a proposition——e.g., difference——though judgments may be so expressed which tell us various things about them: e.g., ‘difference is a relation’ or ‘attracts attention. I must think, severally yet together, of both; and if I want to call attention to them separately, I must indicate them by different signs; but in order to make the judgment, though I need a sign, I do not need to indicate them by different signs. The child that learns to say ‘Pussy’ when it sees the cat means by the single word what we should express by the proposition ‘There is the cat’ or ‘I love the cat,’ or whatever it may be; and Mr. Alfred Jingle expressed his judgments with less than the full complement of words. Whether any thinking can be carried on without some sort of sensible signs (something that suggests the presence or existence of a fact, condition, or quality) is disputed; certainly, it cannot be carried far. I do not imply that some signs are not sensible, but merely wish to call attention to the fact that all are so. The signs need not be written or spoken words; they may be gestures, or sensations of touch, by means of which Helen Keller was taught to think. In algebra, though they can be written, they are not words; in geometry, the figure (a geometric form consisting of any combination of points, lines, or planes) serves to a great extent, and one may think out a demonstration by help of drawing the lines of the construction with less use mentally of words than would be necessary to communicate it. Perhaps, with the figure before one, attending successively to its parts, one may dispense for a time with other signs altogether——other signs, because the figure itself is, as Plato noticed, a sort of sign: our demonstration is not true of it, since it is imperfectly drawn, but it helps us to think of the figure whereof it is true. And perhaps when we are perceiving a thing we can make judgments to ourselves about it, without help of any sign, because it is itself sensible; and when we are not perceiving it, some ‘mental image’ may serve instead of language. For the imagery which accompanies thinking is not the object of thinking; I may as a psychologist make it the object of my thinking, and say that it is vivid, or evanescent, or what not; but that is not the thinking in connection with which it first arises. Its service to thought seems to be comparable with that of words, so that it has been called the ‘inner speech-form’; though it is not articulated as language is. These considerations seem to point to the conclusion that language is necessary to thought because so much that we think of in things is not itself sensible, and we cannot fix our attention on what is not sensible, without the help of something that is; but there need be no correspondence in detail between the sensible sign, and the structure of our thought and of its object. This has not always been realized; and because a child first learns separate words, and then learns to combine them in sentences, and then to combine sentences in continuous discourse, it has sometimes been supposed that thought begins with isolated apprehensions of what it afterwards makes subjects and predicates in judgment, and then builds up judgments into reasoning. Such a view is an illusion produced by language, particularly through the consciousness of the separateness of words which modern writing and reading produces. It is indeed supposed by many that in early language words had not a separate existence, but only existed as it were confluently with one another in sentences. I have seen a letter written by an Alpine guide in admirable French, but wildly at fault in its division of words. Anyhow, there are no ‘ideas’ which we put together in thinking as we do words in speech and writing. No word in philosophy has been responsible for more confusion than the word idea. In Plato, it meant what is called in Logic an universal, the common nature which thought recognizes in different particular things. Nowadays, it sometimes means an opinion (as when I say that my ideas on a subject have changed), sometimes ‘mental images,’ sometimes it is merely an element in a periphrasis: to ‘have an idea of’ is simply to conceive or think of; then we are apt to suppose that we think of things by means of ideas of them, which is no more an explanation of thinking than if I say that I think of things by means of thinking of them. Though the signs by help of which we think are thus various, words are incomparably the most important; and they are almost always the only ones by help of which we express logical doctrine. Words are signs sometimes of things thought of, sometimes of operations of thinking, sometimes of both together. Most writers make some use of symbols which are not words to represent objects of thought (e.g., Arabic numerals); and in Symbolic Logic they are extensively used to represent both objects and operations of thought. The subject-word in a proposition is a sign of something thought of, for which it is said to stand, and the proposition is not about it but about what it stands for: except when we say something about the word itself; an instance of the former is ‘Barkis is willin’,’ of the latter ‘Barkis is a proper name.’ Words like if, because, therefore are signs of the acts of supposition or inference, and is is the sign of the act of judgment, though also implying that something exists. Other verbs, and also adjectives, are signs at once of some object of thought predicated, and of the act of predication; and the same verb may be a sign of the subject of predication as well. Thus in the proposition ‘Dogs bark,’ ‘dogs’ stands for the things about which the statement is made, ‘bark’ both is the sign of (or expresses) what is predicated about them, and also of its being predicated; if I wish to disentangle, as it were, the sign of what is predicated from the sign of predication, I must say ‘Dogs are barking animals,’ or something of that sort. The word Perii expresses both the subject about which the statement is made, viz., the speaker (though it does not stand for it), what is predicated of it, and the act of predication; and if subject and predicate are to be disentangled, one must say ‘I am undone.’ Even here the disentanglement is not complete, because ‘undone’ does not so stand for what is predicated of me that I could make it the subject in another proposition about that; for this purpose, I should have to say ‘I am a man undone’; I could then go on and say ‘A man undone has no energy,’ or whatever it may be. Neither the words ‘a man undone’ nor (in the previous example) ‘barking animals’ stand for the character attributed; that is ‘being undone’ or ‘the habit of barking’; and if we use words that stand for it, and not for the things characterized by it, it cannot be attributed by the verb to be, but by some verb like have——e.g., ‘Dogs have the habit of barking.’ Cf. infra, pp. 37-38. 157. Words are often made signs of these diverse things at once by means of inflection. To substitute for a proposition expressing subject or predicate or both by the same word or words that express also the act of predication another in which distinct words express each of the three is called putting it into logical form. Where (as often in Logic) we wish to make subject and predicate separately subjects of logical discussion, this transformation is necessary, though it often does violence to the idiom of language. Even in a comparatively uninflectional language like English, in a suitable context, a single word may be a proposition: for example, in a telegram, the word ‘coming.’ There is no reason why Logic should ‘put into logical form’ the examples in which it studies thinking, where this is not wished. Now the subject and predicate (Gk. ὑποκείμενον and κατηγορούμενον), but not the act of predication, are called the terms in a judgment; and thus every judgment contains two terms, and they may be called elements in the judgment or the proposition, and it may be said to be resolved into them. This again illustrates how language and thought are bound up together. A proposition is a sentence, but not merely a sentence: it is a sentence expressing or meaning a judgment. Otherwise, we could not speak of resolving it into its terms; for the subject and predicate words, at which we thus arrive, need not have been in the unresolved proposition; and a mere sentence could not be resolved into words that were not in it. Ὄρον καλῶ εἰς ὅν διαλύεται ἡ πρότασις (‘I call that a term into which the proposition is resolved’), Ar. Anal. Pri. a. i. 24b 16. ‘Term’ is terminus, a translation of the Greek ὅρος. It is not quite easy to see why the parts into which the judgment can be broken up were called ὅροι. The statement that ‘a term is so called because it forms one end of a proposition’ (Jevons) is clearly wrong; for that is an accident of language; even in English ‘hungry I was, and ye fed me’ would not be impossible, instead of ‘I was hungry.’ It may be that Aristotle, like the manuscripts of the Organon, symbolized the proposition in the form ‘A-B’ (where we should write ‘B is A’), and that the use of the word comes from the position of the symbols. Bonitz (Index Arist., s.v. ὅρος, 530a 21) thinks it a metaphor from mathematics, where if the ratio of two quantities was considered, these were called ὅροι, being represented by lines, which are the boundaries of a plane; in the judgment, there is a relation of subject and predicate, which might therefore be called ὅροι too. The word is, however, also used like όριο μός, to mean definition; and it may be that subject and predicate were called ὅροι as the determinate objects of our thought in a particular judgment, or as together comprising what is propounded, and limiting the judgment in which they occur to its own field. It is easy then to see that a term is not the same as a word. In a judgment, there are always two terms, but a single word may express both; Caesar’s famous message of three words ‘Veni, vidi, vici’ contains as many distinct propositions, each of which may be resolved into the same subject-term ‘I’ and a predicate-term which is different. Contrariwise, many words may make one term; and this is the most common case. Subject and predicate may each be expressed by a single word, e.g., ‘Tastes differ,’ ‘Regret is foolish’; but in ‘Dead men tell no tales,’ ‘The kingdom of heaven is within you,’ each term consists of several words. Again some words cannot normally be the terms of a proposition at all. They do not indicate by themselves any object of thought, but are either used, like an article, in conjunction with some descriptive word, to designate an object, or, like an adverb, to qualify what another word expresses, or, like a preposition or conjunction, to mark some relation between different parts of a complex object of thought, or (as we have seen) to express an operation of thought. With the articles may be coupled words like some and any; not, and no in ‘no man,’ are also syncategorematic; so is the copula is, as the sign of predication, though not when it means ‘exists’ and is itself the predicate. Such words are called syncategorematic (συνκατηγορηματικά) because only capable of being used along with others in predication; while words which signify what can by itself be a subject or predicate in thought are called categorematic. These, indeed, while capable of being used by themselves as terms, may also enter into a term among the words of which it is composed; thus man is a term in the proposition ‘Man hath found out many inventions,’ but not in the proposition ‘The heart of man is deceitful’: the sea in the proposition ‘The sea shall give up his dead,’ but not in the line ‘She left lonely for ever the kings of the sea.’ In this line the words italicized are syncategorematic; but sea is not syncategorematic, because it can stand for a term, though here it does not do so. Terms composed of words of both kinds have been called ‘mixed terms.’ It is true that syncategorematic words, though standing for nothing whereof anything can be asserted, or which can be asserted of anything, can yet as words be made the subject of linguistic or grammatical discussion, as when we say ‘Of is a preposition,’ or ‘is the sign of the genitive case in English.’ When words which stand for no complete object of thought are made objects of our thought themselves as words, it is said to be by a suppositio materialis. The doctrine of suppositio, as of diverse other ‘properties of terms,’ has happily fallen into oblivion; but for the benefit of anyone who wishes to understand the phrase suppositio materialis it may be worthwhile to add a note on it. All parts of speech were said to have signification; then, as sounds having signification, they acquired properties which did not belong to them as mere sounds. These properties were not the same for every part of speech. Suppositio belonged to substantives denoting substances, copulatio to verbs and adjectives. Substantiality and adjectivality were characters of the things signified; the adjective coupled some adjectival with some substantival thing, the substantive ‘put’ the latter ‘under’ the former (v. Prantl, Geschichte der Logik im Abendlande, vol. II. Abschn. xv. Anm. 67; vol. III. xvii. 59). So far, the sense of suppositio seems to be active; it is defined as acceptio termini substantive pro aliquo; suppositio puts the substantive, instead of what it stands for, under what is adjectival; it takes the substantive term for or as representative of something, and predicates about it. But since we do thus supponere the substantival term, suppositio was said to belong to it, in the sense that not the act of ‘supposition’ belongs to it, but being the subject of that act; and then it was itself said supponere pro aliquo, i.e., to stand for, or be put for (not to put for), something (ct. Prantl, vol. III. xvii. 61, 201: Sanderson’s Compendium Logicae Artis, Lib. Iive. 2). The same term had different kinds of ‘supposition’ according to what it ‘stood for’; e.g., in ‘Homo est animal,’ homo stands for all men, and this is the suppositio naturalis of a common term; in ‘Homo currit,’ it stands for some individual, and this is suppositio personalis. Now as a sound having signification, the term was distinguished into the sound as matter, and the signification as form; and when a predication was true of a term as a sound or in respect of its matter, as in ‘Homo est disyllabum,’ it was said to be by suppositio materialis: when in respect of what it signified, by suppositio formalis. There can be suppositio materialis of any part of speech, but formalis only of substantives; for only a substantive, or substantival phrase (haec enim significat rem ut subsistentem et ordinabilem sub alio, v. Prantl, vol. III. xvii. 60) can have suppositio formalis. Cf. p. 157, infra.