Symbolic logic

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Page 378 - THE PHYSIOLOGY OF MIND ; being the First Part of a Third Edition, Revised, Enlarged, and in great part Rewritten, of "The Physiology and Pathology of Mind.
Page 378 - W. ARCHER BUTLER, late Professor of Moral Philosophy in the University of Dublin. Edited from the Author's MSS., with Notes, by WILLIAM HEPWORTH THOMPSON, MA, Master of Trinity College, and Regius Professor of Greek in the University of Cambridge.
Page 377 - LOGIC. ELEMENTARY LESSONS IN LOGIC; Deductive and Inductive, with copious Questions and Examples, and a Vocabulary of Logical Terms. By W. STANLEY JEVONS, MA, Professor of Political Economy in University College, London. New Edition. Fcap. 8vo. 3*. 6d. " Nothing can be better for a school-book. "-^-GUARDIAN. "A manual alike simple, interesting, and scientific."— ATHHN/UJH.
Page 52 - Tr"1 is defined. Thus it is the office of the inverse symbol to propose a question, not to describe an operation. It is, in its primary meaning, interrogative, not directive. Suppose the given equation to be Then on the above principle of notation we should have...
Page 79 - ... w but are no part of z). It must be admitted that such a diagram is not quite so simple to draw as one might wish it to be; but then consider what the alternative is if one undertakes to deal with five terms and all their combinations; — nothing short of the disagreeable task of writing out, or in some way putting before us, all the 32 combinations involved.
Page 92 - In this respect logical calculations stand in marked contrast with those of mathematics, where economical devices of any kind may subserve a really valuable purpose by enabling us to avoid otherwise inevitable labour. Moreover, in the second place, it does not seem to me that any contrivances at present known or likely to be discovered really deserve the name of logical machines. It is but a very small part of the entire process, which goes to form a piece of reasoning, which they are capable of...
Page 93 - It then becomes a question of judgment which of these is the simplest and best. For instance, in the last example but one, there are a quantity of alternative ways of reading off our conclusion ; and until this is done the problem cannot be said to be solved. I cannot see that any machine can hope to help us except in the third of these steps ; so that it seems very doubtful whether any thing of this sort really deserves the name of a logical engine.
Page 377 - One of the most thoughtful and philosophical treatises on any subject connected with logic and evidence which has been produced in this or any other country for many years.
Page 223 - No one shall be a member both of the general and library committees unless he be also on the financial committee. (3) No member of the library committee shall be on the financial committee.
Page 369 - I have seen no attempt to extend diagrammatic notation to the results of four terms, and it is only quite recently that really adequate figures have been proposed for those of three terms : — for instance both Drobisch and Schroder have used what we may call the three-circle diagram1.

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