FORE:5. The obvious means of attaining this independent movement of the valve gear, is by the momentum of some part set in motion by the hammer-drop, or by the force of gravity reacting on this auxiliary agent.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.
THREE:Again, while attacking the belief in human immortality, Epicurus seems to direct his blows against the metaphysical reasonings of Plato,153 as well as against the indistinct forebod77ings of primitive imagination. The consequences of this two-edged polemic are very remarkable. In reading Lucretius, we are surprised at the total absence of criticisms like those brought to bear on Greek mythology with such formidable effect, first by Plato and, long afterwards, by Lucian. There is a much more modern tone about his invectives, and they seem aimed at an enemy familiar to ourselves. One would suppose that the advent of Catholicism had been revealed in a prophetic vision to the poet, and that this, rather than the religion of his own times, was the object of his wrath and dread; or else that some child of the Renaissance was seeking for a freer utterance of his own revolt against all theology, under the disguise of a dead language and of a warfare with long-discredited gods. For this reason, Christians have always regarded him, with perfect justice, as a dangerous enemy; while rationalists of the fiercer type have accepted his splendid denunciations as the appropriate expression of their own most cherished feelings.In business arrangements, technical knowledge and professional experience become capital, and offset money or property, not under any general rule, nor even as a consideration of which the law can define the value or prescribe conditions for. The estimate placed upon technical knowledge when rated as capital in the organisation of business firms, and wherever it becomes [21] necessary to give such knowledge a commercial value, furnishes the best and almost the only source from which an apprentice can form an opinion of the money value of what he is to acquire during his apprenticeship.
THREE:It is never enough to know that any piece of work is commonly constructed in some particular manner, or that a proposition is generally accepted as being correct; a reason should be sought for. Nothing is learned, in the true sense, until the reasons for it are understood, and it is by no means sufficient to know from observation alone that belts are best for high speeds, that gearing is the best means of forming angles in transmitting power, or that gearing consumes more power, and that belts produce less jar and noise; the principles which lie at the bottom must be reached before it can be assumed that the matter is fairly understood.
THREE:Meanwhile, hedonism had been temporarily taken up by Plato, and developed into the earliest known form of utilitarianism. In his Protagoras, he endeavours to show that every virtue has for its object either to secure a greater pleasure by the sacrifice of a lesser pleasure, or to avoid a greater pain by the endurance of a lesser pain; nothing being taken into account but the interests of the individual agent concerned. Plato afterwards discarded the theory sketched in the Protagoras for a higher and more generous, if less distinctly formulated morality; but while ceasing to be a hedonist he remained a utilitarian; that is to say, he insisted on judging actions by their tendency to promote the general welfare, not by the sentiments which they excite in the mind of a conventional spectator.230
