TWO:Passing from life to mind, we find Empedocles teaching an even more pronounced materialism than Parmenides, inasmuch as it is stated in language of superior precision. Our souls are, according to him, made up of elements like those which constitute the external world, each of these being perceived by a corresponding portion of the same substances within ourselvesfire by fire, water by water, and so on with the rest. It is a mistake to suppose that speculation begins from a subjective standpoint, that men start with a clear consciousness of their own personality, and proceed to construct an objective universe after the same pattern. Doubtless they are too prone to personify the blind forces of Nature, and Empedocles himself has just supplied us with an example of this tendency, but they err still more by reading outward experience into their own souls, by materialising the processes of consciousness, and resolving human personality into a loose confederacy of inorganic units. Even Plato, who did more than anyone else towards distinguishing between mind and body, ended by laying down his psychology on the lines of an astronomical system. Meanwhile, to have separated the perception of an object from the object itself, in ever so slight a degree, was an important gain to thought.33 We must not omit to notice a hypothesis by which Empedocles sought to elucidate the mechanism of sensation, and which was subsequently adopted by the atomic school; indeed, as will presently be shown, we have reason to believe that the whole atomic theory was developed out of it. He held that emanations were being continually thrown off from the surfaces of bodies, and that they penetrated into the organs of sense through fine passages or pores. This may seem a crude guess, but it is at any rate much more scientific than Aristotles explanation. According to the latter, possibilities of feeling are converted into actualities by the presence of an object. In other words, we feel when and because we do; a safe assertion, but hardly an addition to our positive knowledge of the subject.
TWO:Prout gave his information in a low voice. He could trust Hetty, and besides, she might have some valuable information to impart."Now we come to the marvellous evidence against Bruce. There you had stolen my plot, body and boots. Bruce is poor, so was my hero. You find out all about that picture he bought, and Balmayne or somebody--it does not in the least matter who--in the guise of a Dutchman puts Bruce in possession of 200. These notes he places in his pocket.
TWO:The time in which the contraction takes place is as the temperature of the bath and the cross section of the piece; in other words the heat passes off gradually from the surface to the centre.
It was a little before eleven that Balmayne came in. He was very quiet and subdued; he sat and unfolded an evening paper. He shot a sign across to the Countess from a pair of eyes that gleamed like flames.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.CHAPTER XIV
荣誉榜
THREE:The End
THREE:
