=161.= So far we find in the Stoic system the general framework of the grammar of the period, much of it adapted with modifications from Aristotle. In some other details points of real grammatical or philosophical interest are raised. Such is the controversy between ‘anomaly,’ the recognition of the individuality of each word in its flexion, and ‘analogy,’ in which the validity of the rules of declension and conjugation is insisted upon. Two Stoic masters, Chrysippus and Crates of Mallos, took up the cause of ‘anomaly[104].’ Further the Stoics held that all correct language exists by nature (φύσει), and not by convention (θέσει), as Aristotle had maintained; the elements of language being imitations of natural sounds[105]. Further, they held that the natural relation between ‘things’ (σημαινόμενα, _significata_) and the words that express them (σημαίνοντα, _significantia_) can frequently be determined by etymology; for instance φωνή ‘voice’ is φῶς νοῦ ‘the mind’s lamp,’ αἰών ‘age’ is ἀεὶ ὄν ‘enduring for ever[106].’ Like Heraclitus and Aristotle, the Stoics distinguished between ‘thought’ (λόγος ἐνδιάθετος, _ratio_) and ‘speech’ (λόγος προφορικός, _oratio_), which the Greek word λόγος tends to confuse[107]; thought is immaterial, but speech, as consisting of air in motion, is body[108]. Young children and animals do not possess real speech, but only ‘a sort of speech[109].’ [Sidenote: Propositions and Syllogisms.] =162.= Words in combination form statements, questions, wishes, syllogisms, and so forth[110]; there is therefore no clear line drawn between what we call syntax and logic respectively. Whenever we have a complete combination of words expressing that which must either be false or true, as ‘Hannibal was a Carthaginian,’ ‘Scipio destroyed Numantia,’ we call it a ‘statement’ or ‘proposition’ (ἀξίωμα)[111]; for phrases of all kinds we have the more general term ‘phrase’ (λεκτόν, _id quod dicitur_)[112]. Of special interest is the conditional sentence (συνημμένον), which has two parts, the conditional clause (ἡγούμενον) and the contingent clause (λῆγον). The conditional or leading clause always contains a sign (σημεῖον), by means of which we reach proof: thus in saying ‘if it is day, it is light’ we mean that ‘day’ is a sign of light. Proof is ‘speech on every subject gathering what is less clear from that which is more clear[113].’ Its most important form is the syllogism, of which Chrysippus recognises five forms: (i) if A, then B; but A, therefore B. (ii) if A, then B; but not B, therefore not A. (iii) not A and B together; but A, therefore not B. (iv) either A or B; but A, therefore not B. (v) either A or B; but not A, therefore B[114]. All these matters admit of endless qualifications, subdivisions, and developments, and were therefore serviceable to those Stoics who were before all things makers of books[115]. Examples of Stoic syllogisms have been given above[116]. [Sidenote: Fallacies.]