It is well known that Spinoza draws a sharp line of demarcation between the two attributes of Extension and Thought, which, with him, correspond to what are usually called body and mind. Neither attribute can act on the other. Mind receives no impressions from body, nor does body receive any impulses from mind. This proposition follows by rigorous logical necessity from the Platonic principle that mind is independent of body, combined with the Stoic principle that nothing but body can act on body, generalised into the wider principle that interaction implies homogeneity of nature. According to some critics, Spinozas teaching on this point constitutes a fatal flaw in his philosophy. How, it is asked, can we know that there is any such thing as body (or extension) if body cannot be perceived,for perceived it certainly cannot be without acting on our minds? The idea of infinite substance suggests a way out of the408 difficulty. I find in myself, Spinoza might say, the idea of extension. In fact, my mind is nothing but the idea of extension, or the idea of that idea, and so on through as many self-reflections as you please. At the same time, mind, or thought, is not itself extended. Descartes and the Platonists before him have proved thus much. Consequently I can conceive extension as existing independently of myself, and, more generally, of all thought. But how can I be sure that it actually does so exist? In this wise. An examination of thought leads me to the notion of something in which it residesa substance whose attribute it is. But having once conceived such a substance, I cannot limit it to a single attribute, nor to two, nor to any finite number. Limitation implies a boundary, and there can be no boundary assigned to existence, for existence by its very definition includes everything that is. Accordingly, whatever can be conceived, in other words whatever can be thought without involving a contradiction,an important reservation which I beg you to observe,must necessarily exist. Now extension involves no contradiction, therefore it exists,exists, that is to say, as an attribute of the infinite substance. And, by parity of reasoning, there must be an idea of extension; for this also can exist without involving a contradiction, as the simplest introspection suffices to show. You ask me why then I do not believe in gorgons and chimaeras. I answer that since, in point of fact, they do not exist, I presume that their notion involves a contradiction, although my knowledge of natural law is not sufficiently extended to show me where the contradiction lies. But perhaps science will some day be able to point out in every instance of a non-existing thing, where the contradiction lies, no less surely than it can now be pointed out in the case of impossible geometrical figures. In short, while other people travel straight from their sensations to an external world, Spinoza travels round to it by the idea of an infinite substance.564Landor himself sat in his tent, upon his mess-chest, and by the light of a candle wrote a despatch which[Pg 8] was to go by courier the next morning. Gila valley mosquitoes were singing around his head, a knot of chattering squaws and naked children were peering into his tent, the air was oven-hot, coyotes were filling the night with their weird bark, and a papoose was bawling somewhere close by. Yet he would have been sufficiently content could he have been let alonethe one plea of the body military from all time. It was not to be. The declared and standing foes of that body pushed their way through the squaws and children. He knew them already. They were Stone of the Tucson press, sent down to investigate and report, and Barnwell, an Agency high official, who would gladly assist the misrepresentations, so far as in his power lay.And things were coming to an end, anyway. He could see it in the looks of the Apaches, and hear it in their whispers. They consented to come in, and even to put themselves at the discretion of the government, but there was a lack of the true ring in their promises. So when, on the third morning, before it was yet daylight, two chiefs came hurrying into camp and awoke the general with bad news, he was not greatly surprised. He had warned Crook of the possibility, for that matter.The greatest of Roman orators and writers was also the first Roman that held opinions of his own in philosophy. How much original thought occurs in his voluminous contributions to the literature of the subject is more than we can determine, the Greek authorities on which he drew being known almost exclusively through the references to them contained in his disquisitions. But, judging from the evidence before us, carefully sifted as it has been by German scholars, we should feel disposed to assign him a foremost rank among the thinkers of an age certainly not distinguished either for fertility or for depth of thought. It seems clear that he gave a new basis to the eclectic tendencies of his contemporaries, and that this basis was subsequently accepted by other philosophers whose speculative capacity has never been questioned. Cicero describes himself as an adherent of the New Academy, and expressly claims to have reasserted its principles after they had fallen into neglect among the Greeks, more particularly as against his own old master Antiochus, whose Stoicising theory of cognition he agrees with Philo in repudiating.269 Like Philo also, he bases certainty on the twofold ground of a moral necessity for acting on our beliefs,270 and the existence of moral intuitions, or natural tendencies to believe in the mind itself;271 or, perhaps, more properly speaking, on the single ground of a moral sense. This, as already stated, was unquestionably a reproduction of the Platonic ideas under their subjective aspect. But in his general views about the nature and limits171 of human knowledge, Cicero leaves the Academy behind him, and goes back to Socrates. Perhaps no two men of great genius could be more unlike than these two,for us the most living figures in ancient history if not in all history,the Roman being as much a type of time-servingness and vacillation as the Athenian was of consistency and resolute independence. Yet, in its mere external results, the philosophy of Socrates is perhaps more faithfully reproduced by Cicero than by any subsequent enquirer; and the differences between them are easily accounted for by the long interval separating their ages from one another. Each set out with the same eager desire to collect knowledge from every quarter; each sought above all things for that kind of knowledge which seemed to be of the greatest practical importance; and each was led to believe that this did not include speculations relating to the physical world; one great motive to the partial scepticism professed by both being the irreconcilable disagreement of those who had attempted an explanation of its mysteries. The deeper ground of mans ignorance in this respect was stated somewhat differently by each; or perhaps we should say that the same reason is expressed in a mythical form by the one and in a scientific form by the other. Socrates held that the nature of things is a secret which the gods have reserved for themselves; while, in Ciceros opinion, the heavens are so remote, the interior of the earth so dark, the mechanism of our own bodies so complicated and subtle, as to be placed beyond the reach of fruitful observation.272 Nor did this deprivation seem any great hardship to either, since, as citizens of great and free states, both were pre-eminently interested in the study of social life; and it is characteristic of their common tendency that both should have been not only great talkers and observers but also great readers of ancient literature.273
