ONE:A machine may be mechanically correct, arranged with symmetry, true proportions, and proper movements; but if such a machine has not commercial value, and is not applicable to a useful purpose, it is as much a failure as though it were mechanically inoperative. In fact, this consideration of cost and commercial value must be continually present; and a mechanical education that has not furnished a true understanding of the relations between commercial cost and mechanical excellence will fall short of achieving the objects for which such an education is undertaken. By reasoning from such premises as have been laid down, an apprentice may form true standards by which to judge of plans and processes that he is brought in contact with, and the objects for which they are conducted.
TWO:
ONE:Before parting with the Poetics we must add that it contains one excellent piece of advice to dramatists, which is, to imagine themselves present at the scenes which they are supposing to happen, and also at the representation of their own play. This, however, is an exception which proves the rule, for Aristotles exclusively theoretic standpoint here, as will sometimes happen, coincides with the truly practical standpoint.Leona quivered but said nothing. It was only by a motion of her hand that she signalled Lawrence to proceed.
TWO:Whether there exist any realities beyond what are revealed to us by this evidence, and what sensible evidence itself may be worth, were problems already actively canvassed in Aristotles time. His Metaphysics at once takes us into the thick of the debate. The first question of that age was, What are the causes and principles of things? On one side stood the materialiststhe old Ionian physicists and their living representatives. They said that all things came from water or air or fire, or from a mixture of the four elements, or from the interaction of opposites, such as wet and dry, hot and cold.332 Aristotle, following in the track of his master, Plato, blames them for ignoring the incorporeal substances, by which he does not mean what would now be understoodfeelings or states of consciousness, or even the spiritual substratum of consciousnessbut rather the general qualities or assemblages of qualities which remain constant amid the fluctuations of sensible phenomena; considered, let us observe, not as subjective thoughts, but as objective realities. Another deficiency in the older physical theories is that they either ignore the efficient cause of motion altogether (like Thales), or assign causes not adequate to the purpose (like Empedocles); or when they hit on the true cause do not make the right use of it (like Anaxagoras). Lastly, they have omitted to study the final cause of a thingthe good for which it exists.What influence Scepticism exercised on the subsequent course of Greek thought is difficult to determine. If we are to believe Diogenes Laertius, who flourished in the second quarter of the third century A.D., every school except Epicureanism had at that time sunk into utter neglect;304 and it is natural to connect this catastrophe with the activity of the Sceptics, and especially of Sextus Empiricus, whose critical compilation had appeared not long before. Such a conclusion would be supported by the circumstance that Lucian, writing more than fifty years earlier, directs his attacks on contemporary philosophy chiefly from the Sceptical standpoint; his Hermotimus in particular being a popularised version of the chief difficulties raised from that quarter. Still it remains to be shown why the criticism of the Greek Humanists, of Pyrrho, and of the New Academy should have produced so much more powerful an effect under their revived form than when they were first promulgated; and it may be asked whether the decline of philosophy should not rather be attributed to the general barbarisation of the Roman empire at that period.
