FORE:II.In the theory of reasoning the simple proposition is taken as a starting-point; but instead of deducing the syllogism379 from the synthesis of two premises, Aristotle reaches the premises through the conclusion. He tells us, indeed, that reasoning is a way of discovering from what we know, something that we did not know before. With him, however, it is really a process not of discovery but of proof. He starts with the conclusion, analyses it into predicate and subject or major and minor, and then, by a further analysis, introduces a middle term connecting the two. Thus, we begin with the proposition, Caius is mortal, and prove it by interpolating the notion humanity between its two extremes. From this point of view the premises are merely a temporary scaffolding for bringing the major and minor into connexion with the middle term; and this is also the reason why Aristotle recognises three syllogistic figures only, instead of the four admitted by later logicians. For, the middle may either be contained in one extreme and contain the other, which gives us the first figure; or it may contain both, which gives the second figure; or be contained in both, which gives the third; and this is an exhaustive enumeration of the possible combinations.274
FORE:A book containing the pattern record should be kept, in which these catalogue numbers are set down, with a short description to identify the different parts to which the numbers belong, so that all the various details of any machine can at any time be referred to. Besides this description, there should be opposite the catalogue of pattern numbers, ruled spaces, in which to enter the weight of castings, the cost of the pattern, and also the amount of turned, planed, or bored surface on each piece when it is finished, or the time required in fitting, which is the same thing. In this book the assembled parts of each machine should be set down in a separate list, so that orders for castings can be made from the list without other references. This system is the best one known to the writer, and is in substance a plan now adopted in many of the best engineering establishments. A complete system in all things pertaining to drawings and classifications should be rigidly adhered to; any plan is better than none, and the schooling of the mind to be had in the observance of systematic rules is a matter not to be neglected. New plans for promoting system may at any time arise, but such plans cannot be at any [87] time understood and adopted except by those who have cultivated a taste for order and regularity.