THREE:Before entering on the chain of reasoning which led Aristotle to postulate the existence of a personal First Cause, we must explain the difference between his scientific standpoint, and that which is now accepted by all educated minds. To him the eternity not only of Matter, but also of what he called Form,that is to say, the collection of attributes giving definiteness to natural aggregates, more especially those known as organic specieswas an axiomatic certainty. Every type, capable of self-propagation, that could exist at all, had existed, and would continue to exist for ever. For this, no explanation beyond the generative power of Nature was required. But when he had to account for the machinery by which the perpetual alternation of birth and death below, and the changeless revolutions of the celestial spheres above the moon were preserved, difficulties arose. He had reduced every other change to transport through space; and with regard to this his conceptions were entirely mistaken. He believed that moving matter tended to stop unless it was sustained by some external force; and whatever their advantages over him in other respects, we cannot say that the Atomists were in a position to correct him here: for their349 theory, that every particle of matter gravitated downward through infinite space, was quite incompatible with the latest astronomical discoveries. Aristotle triumphantly showed that the tendency of heavy bodies was not to move indefinitely downwards in parallel lines, but to move in converging lines to the centre of the earth, which he, in common with most Greek astronomers, supposed to be also the centre of the universe; and seeing light bodies move up, he credited them with an equal and opposite tendency to the circumference of the universe, which, like Parmenides and Plato, he believed to be of finite extent. Thus each kind of matter has its appropriate place, motion to which ends in rest, while motion away from it, being constrained, cannot last. Accordingly, the constant periodicity of terrestrial phenomena necessitates as constant a transformation of dry and wet, and of hot and cold bodies into one another. This is explained with perfect accuracy by the diurnal and annual revolutions of the sun. Here, however, we are introduced to a new kind of motion, which, instead of being rectilinear and finite, is circular and eternal. To account for it, Aristotle assumes a fifth element entirely different in character from the four terrestrial elements. Unlike them, it is absolutely simple, and has a correspondingly simple mode of motion, which, as our philosopher erroneously supposes, can be no other than circular rotation.Again, the new position occupied by Mind as an intermediary between the world of reality and the world of appearance, tended more and more to obliterate or confuse the demarcations by which they had hitherto been separated. The most general headings under which it was usual to contrast them were, the One and the Many, Being and Nothing, the Same and the Different, Rest and Motion. Parmenides employed the one set of terms to describe his Absolute, and the other to describe the objects of vulgar belief. They also served respectively to designate the wise and the ignorant, the dialectician and the sophist, the knowledge of gods and the opinions of men; besides offering points of contact with the antithetical couples of Pythagoreanism. But Plato gradually found that the nature of Mind could not be understood without taking both points of view into account. Unity and plurality, sameness and difference, equally entered into its composition; although undoubtedly belonging to the sphere of reality, it was self264-moved and the cause of all motion in other things. The dialectic or classificatory method, with its progressive series of differentiations and assimilations, also involved a continual use of categories which were held to be mutually exclusive. And on proceeding to an examination of the summa genera, the highest and most abstract ideas which it had been sought to distinguish by their absolute purity and simplicity from the shifting chaos of sensible phenomena, Plato discovered that even these were reduced to a maze of confusion and contradiction by a sincere application of the cross-examining elenchus. For example, to predicate being of the One was to mix it up with a heterogeneous idea and let in the very plurality which it denied. To distinguish them was to predicate difference of both, and thus open the door to fresh embarrassments.
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THREE:
THREE:Forges, pneumatic machinery for blast, machinery for handling large pieces, and other details connected with forging, are easily understood from examples.
THREE:CHAPTER VII
