THREE:The famous theses of Gorgias were quoted in a former chapter as an illustration of the tactics pursued by Greek Humanism in its controversy with physical science. They must be noticed again in the present connexion, on account of their bearing on the development of scepticism, and as having inaugurated a method of reasoning often employed in subsequent attacks, directed, not against the whole of knowledge, but against particular parts of it. The scepticism of Protagoras rested on the assumption that there is an external reality from the reaction of which with mind all our perceptions proceed. Neither of these two factors can be known apart from the other, and as both are in a constant flux, our knowledge of the resulting compound at one time does not show what it has been or will be at another time. But Gorgias altogether denied the existence of any objective reality; and he attempted to disprove it by an analytical instead of a synthetic argument, laying down a series of disjunctive propositions, and upsetting the different alternatives in succession. Existence must be either something or nothing, or both together; and if something, it must be either finite or infinite, or both, and either one or many, or both. His argument against an infinite existence is altogether futile; but it serves to illustrate the undeveloped state of reflection at that period. The eternity of the world is confounded with its unlimited extension in space: and this hypothesis, again, is met by the transparent quibble that the world, not being in any one place, must be nowhere or not at all. And the alternative that the world has not always existed is refuted by the unproved assumption, which, apparently, no Greek philosopher ever thought of disputing, that nothing can begin without being caused by something else. Still, however contemptible such reasonings may seem,131 it is obvious that in them we have the first crude form of the famous antinomies by which Kant long afterwards sought to prove the impossibility of a world existing in space and time apart from a percipient subject, and which have since been used to establish in a more general way the unknowability of existence as such. It will also be observed that the sceptical arguments respectively derived from the relativity of thought and from the contradictions inherent in its ultimate products are run together by modern agnostics. But no reason that we can remember has ever been given to show that an idea is necessarily subjective because it is self-contradictory.We have seen how Greek thought had arrived at a perfectly just conception of the process by which all physical transformations are effected. The whole extended universe is an aggregate of bodies, while each single body is formed by a combination of everlasting elements, and is destroyed by their separation. But if Empedocles was right, if these primary substances were no other than the fire, air, water, and earth of everyday experience, what became of the Heracleitean law, confirmed by common observation, that, so far from remaining unaltered, they were continually passing into one another? To this question the atomic theory gave an answer so conclusive, that, although ignored or contemned by later schools, it was revived with the great revival of science in the sixteenth century, was successfully employed in the explanation of every order of phenomena, and still remains the basis of all physical enquiry. The undulatory theory of light, the law of universal gravitation, and the laws of chemical combination can only be expressed in terms implying the existence of atoms; the laws of gaseous diffusion, and of thermodynamics generally, can only be understood with their help; and the latest develop34ments of chemistry have tended still further to establish their reality, as well as to elucidate their remarkable properties. In the absence of sufficient information, it is difficult to determine by what steps this admirable hypothesis was evolved. Yet, even without external evidence, we may fairly conjecture that, sooner or later, some philosopher, possessed of a high generalising faculty, would infer that if bodies are continually throwing off a flux of infinitesimal particles from their surfaces, they must be similarly subdivided all through; and that if the organs of sense are honeycombed with imperceptible pores, such may also be the universal constitution of matter.26 Now, according to Aristotle, Leucippus, the founder of atomism, did actually use the second of these arguments, and employed it in particular to prove the existence of indivisible solids.27 Other considerations equally obvious suggested themselves from another quarter. If all change was expressible in terms of matter and motion, then gradual change implied interstitial motion, which again involved the necessity of fine pores to serve as channels for the incoming and outgoing molecular streams. Nor, as was supposed, could motion of any kind be conceived without a vacuum, the second great postulate of the atomic theory. Here its advocates directly joined issue with Parmenides. The chief of the Eleatic school had, as we have seen, presented being under the form of a homogeneous sphere, absolutely continuous but limited in extent. Space dissociated from matter was to him, as afterwards to Aristotle, non-existent and impossible. It was, he exclaimed, inconceivable, nonsensical. Unhappily inconceivability is about the worst negative criterion of truth ever yet invented. His challenge was now35 taken up by the Atomists, who boldly affirmed that if non-being meant empty space, it was just as conceivable and just as necessary as being. A further stimulus may have been received from the Pythagorean school, whose doctrines had, just at this time, been systematised and committed to writing by Philolaus, its most eminent disciple. The hard saying that all things were made out of number might be explained and confirmed if the integers were interpreted as material atoms.
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Lorem ipsum dolor sit amet, consectetur adipisicing elit. Aliquam aut tenetur, amet earum quia eligendi obcaecati. Repudiandae id illum, vero iste enim reprehenderit quaerat, harum pariatur ipsa nulla tempora ex ratione illo assumenda libero ea, delectus vitae, expedita optio porro.
Lorem ipsum dolor sit amet, consectetur adipisicing elit. Aliquam aut tenetur, amet earum quia eligendi obcaecati. Repudiandae id illum, vero iste enim reprehenderit quaerat, harum pariatur ipsa nulla tempora ex ratione illo assumenda libero ea, delectus vitae, expedita optio porro.
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ONE:Seventh.There is no waste of power by slipping belts or other frictional contrivances to graduate motion; and finally, there is no machinery to be kept in motion when the hammer is not at work.
