The Principles of Logic: For High Schools and Colleges |
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angles antecedent Assumptions arising attributes cause circle of latitude Classification clusion coextensive comprehensive conceive consequent contained contrary coördinate Definition denotes Denying the antecedent Disjunctive Syllogisms distribute the predicate division earth Enthymeme Euathlus excluded expression extension extensive quantity fact fallacy false finite foreknown Formal fallacies free agent genus Hamilton harmony of thought Hence hypothesis Hypothetical Hypothetical Syllogisms illicit process implies the falsity implies the truth individual infer intersects invalid judgment knowledge Law of Contradictories laws of thought logical major premise major term Mathematical Induction method middle term mind minor term moon motion nature non-P is Q non-S objects observed order to distribute particular premises petitio principii phenomena Prem principle proposition prove quantity Real induction reason relation responsible agent Sophisms space is infinite species subordinate theological conceptions thing tion tive tower triangle true undistributed middle valid moods warrant whole
Popular passages
Page 143 - To make the comprehensibility of a datum of consciousness the criterion of its truth would be, indeed, the climax of absurdity. For the primary data of consciousness as themselves the conditions under which all else is comprehended, are necessarily themselves incomprehensible. We know, and can know only, that they are, not how they can be.
Page 146 - It must be granted that in every syllogism, considered as an argument to prove the conclusion, there is a petitio principii. When we say, All men are mortal, Socrates is a man, therefore Socrates is mortal; it is unanswerably urged by the adversaries of the syllogistic theory, that the proposition, Socrates is mortal...
Page 49 - Let us now take an argument with an undistributed middle : All P is M. All S is M. .-. All S is P. The conclusion does not necessarily follow from the premises, though it may be accidentally true, as seen in the second diagram above. Let now the major premise be a case of coextension, then M will be distributed and the argument valid. All P is M. All S is M.
Page 146 - All men are mortal'; that the general principle, instead of being given as evidence of the particular case, cannot itself be taken for true without exception, until every shadow of doubt which could affect any case comprised with it is dispelled by evidence...
Page 98 - Nothing, it may be observed, is more easy than to misapply a form ; nothing more easy than to use a weaker, when we are entitled to use a stronger proposition. But from the special and factitious absurdity thus emerging, to infer the general and natural absurdity of the prepositional form itself, — this is, certainly, not a logical procedure.
Page 142 - Now let us try positively to comprehend, positively to conceive, the possibility of either of these two mutually exclusive alternatives. Can we represent or realize in thought, extension as absolutely limited ? in other words, can we mentally hedge round the whole of space, conceive it absolutely bounded, that is, so that beyond its boundary, there is no outlying, no surrounding space ? This is impossible.
Page 119 - A miracle is an effect or event contrary to the established constitution or course, of things, or a sensible suspension or controlment of, or deviation from, the known laws of nature...
Page 153 - Thus, that the square of the hypothenuse of a right-angled triangle is equal to the sum of the squares of the other two sides, was an experimental discovery, or why did the discoverer sacrifice a hecatomb when he made out its proof ?
Page 97 - But again (to prove both the obnoxious propositions summarily and at once) — what objection, apart from the arbitrary laws of our present logical system, can be taken to the following syllogism ? All man is some animal. Any man is not (no man is) some animal. Therefore some animal is not some animal.