Combination.
186. Having fully considered bodies and their relationships, we proceed to consider their combination. In ordinary experience we meet with three kinds of combination; juxtaposition (παράθεσις), as in a mixture of various kinds of grain; mixture (μῖξις), when solid bodies are interfused, as fire and heat, or fusion (κρᾶσις), when fluids are interfused, as wine poured into the sea; chemical mixture (σύγχυσις), when each of the two bodies fused disappears[78]. Of these the second in its most completed form (κρᾶσις δι’ ὅλων, universa fusio) is of high importance. For in this way we find that soul is fused with body[79], quality with substance[80], light with air[81], God with the universe[82]. Aristotle admits that there is this mixture between substance and qualities; but as both of these are to the Stoics bodies, and so too are the members of the other pairs quoted, the Stoic doctrine must be summed up in the paradox ‘body moves through body[83].’ This also follows from the Stoic doctrine that there is no void in the universe. Correspondingly the sum total of body in its various aspects and mixtures completes the whole (ὅλον), which is identical with the ‘world-order’ or ‘universe’ (κόσμος)[84]. It seems likely that this important conception had been reached in very early times by the Chaldaean astronomers; it was definitely propounded by Pythagoras[85], had been taken up by Socrates[86] and the Sophists[87], and was in Stoic times generally accepted both in popular philosophy and in scientific investigation.
Quiddities.
187. Up to this point the Stoic system has been guided by a determined monism. Body is; that which is not body is not. Yet in the end the Stoics feel compelled to speak of certain things which are not body (ἀσώματα, incorporalia). In the first instance there is the void beyond the universe[88]. It is possible to dispute as to whether void may more correctly be said to exist or not to exist; but at least it is a part of nature[89], and we need some term like ‘the all’ (τὸ πᾶν) to include both the universe and the void beyond[90]. Next we have to deal with statements (λεκτά), and mental conceptions of every kind, which stand as a class in contrast with the real objects to which they may or may not respectively correspond[91]. Lastly, the Stoics included space and time, which they had previously explained as functions of body, in the list of things not bodily[92]. Having thus reached the two main classes of ‘bodies,’ and ‘things not bodily,’ the monistic principle can only be saved by creating a supreme class to include both. Let this then be called the existent (τὸ ὄν, quod est)[93], or, if it be objected that things incorporeal do not exist[94], we may use the name ‘quiddities’ (τινά, quid)[95]. In this way the monistic theory, though a little damaged in vitality, is again set on its feet so far as the ingenious use of words can help.
Statements.
188. The language of the Stoics with regard to the phenomena of speech and thought is not always easy to follow, and perhaps not altogether consistent. On the one hand, attaching high importance to the reasoning power, they desire to include its operations in that which is real and bodily. Thus the ‘mind-pictures’ and indeed all mental conceptions are bodily and even ‘animal,’ in the sense that they are operations of body[96]; and truthfulness, ignorance, science and art are all bodies in the sense that they are dispositions of the soul, which is bodily[97]. But ‘phrases’ (λεκτά) are definitely incorporeal, and with them appear to be ranked all mental conceptions and general ideas; about these there is a question, not merely whether they exist or not, but whether they may even be classed in the most general class of all as ‘quiddities[98].’ Nor can we call general conceptions true or false[99]; though of some of them, as of Centaurs, giants, and the like, we may say that they are formed by false mental processes[100]. Finally statements are either true or false, but are not to be called existent. The whole discussion therefore ends with the broad distinction between the object, which may be real or ‘existent,’ and the predication which may be ‘true’; and the attempt to unite these two conceptions is not persisted in[101].
Force and matter.
189. Although the Stoics aim consistently at the monistic standard, they make frequent use of dualistic statements, some of which we have already noticed. The Latin writers often contrast soul and body from the standpoint of ethics[102]; and we meet in all the Stoic writers, and often in unguarded language, the favourite Aristotelian dualism of force and matter, or (what comes to the same thing) the active and passive principles. ‘Zeno’ (we are told) ‘laid down that there are two principles in the universe, the active and the passive. The passive is matter, or essence without quality; the active is the Logos or deity within it[103].’ So also Cleanthes and Chrysippus taught[104]; and in the Roman period Seneca regarded this as a well-understood dogma of the whole school[105]. But even if direct evidence were lacking, the whole bearing of the philosophy would shew that this dualism is also surmounted by an ultimate monism. God and matter are alike body; they cannot exist the one apart from the other[106]. Of this Cicero, speaking for the Stoics, gives a proof; matter could never have held together, without some force to bind it; nor force without matter[107]. We must not therefore be led by the term ‘principles’ (ἀρχαί, principia) to think of force and matter in any other way than as two aspects of primary body, separable as mental conceptions, inseparable as physical realities. The interpretation is essentially the same, whether the Stoics speak of God and the universe, matter and cause, body and tension, or substance and quality, and has been already discussed with some fulness under these separate headings.
The elements.
190. The position of the four ‘elements’ (στοιχεῖα, elementa) is similar; these are in the Stoic philosophy subdivisions of the two principles just discussed. For fire and air are of the nature of cause and movement; water and earth of receptivity and passivity[108]. Body is therefore made up of the four elements mixed[109], or perhaps rather of the elementary qualities of heat and cold, dry and wet, which they represent[110]. The doctrine of primary or elemental qualities had been taught before, first by Anaximenes, then by Hippocrates the physician, and by Aristotle[111]; the list of the four elements is traced back to Empedocles. For Aristotle’s ‘fifth element’ Zeno found no use[112].