A new logic / by Charles Mercier.

  • Mercier, Charles Arthur, 1852-1919.
Date:
1912
Catalogue details

Licence: In copyright

Credit: A new logic / by Charles Mercier. Source: Wellcome Collection.

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    in any way we please, so long as we preserve the consistency of the product with the original. Hence this field of Logic is sometimes called the Logic of Consistency. There is yet a third method by which new propositions are constructed by the art of reasoning. Two relations may be compared, and may be discerned to be like or unlike ; and this likeness or unlikeness may be stated in a proposition. It is evident that this method of forming propositions is, like the last, independent of any appeal to experience, and so differs from the first mode of reasoning. It differs also from the second mode, for it makes no alteration in the propositions it compares, nor does it pay any regard to their consistency or inconsistency. It looks to nothing but the likeness or unlikeness of the relations they express. The first of these three modes of reasoning is Empirical Reasoning, so called because an appeal to experience is an integral and indispensable part of the process. It is the Logic of Discovery; of Truth; of Fact; of Matter. It is coterminous with Induction, as Induction ought to be understood ; but the view that is here taken of the mode of discovering truth by Inductive reasoning, is not the same as the prevalent doctrine of Induction, though it is called by the same name. The true process of Induc- tion seems to me very different from that which is usually so called, as is explained in the second Book, which is devoted to this mode of Reasoning. The second mode of reasoning includes the Immediate and Mediate Deduction, or Inference, of Traditional Logic, and it includes a great deal more. The inferences deduced in the text books from simple and compound propositions, are but a small fraction of those that can be deduced by proper methods, which are set forth in the third Book. The Logic expounded in that book is the Logic of Inference; of Consistency; of Proof and Disproof ; of Form. Useless in the discovery of Fact ; ignoring the truth or falsity of the matter of which it treats; its value is in testing Consistency ; in argument; in explicating ; convincing ; refuting. This is the field of Traditional Logic. The third mode of reasoning is the Logic of Analogy. As con- cerned with qualitative relations, it aids neither Discovery nor Proof. It is concerned neither with Fact nor with Consistency. Its sole value is in explaining, expounding and enforcing statements.