Logic Notebook 1865-7

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LOGIC

(1886) 1865-7

Last edit almost 2 years ago by jeffdown1
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Miscellaneous Observations

12 Nov. 1865

What is a real definition? A definition of a word whose essence lies in its denotation.

12 Nov. 1865

There are three forms of question

1 Are quadrupeds animals?

2 Are there quadruped animals?

3 Are quadruped animals either quadruped or animal?

The affirmative answers will be

To 1. Universal Affirmative. Yes. Quadrupeds are animals.

To 2. Particular Affirmative. Yes. Quadruped animals exist.

To 3. Universal Negative. Yes. There is no animal quadruped.

Nov. 14

There is no difference logically between hypotheticals & ... The subject is a sign of the predicate, the antecedent of the consequent, and this is the only point that concerns logic.

Last edit about 1 year ago by cumont8
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reduced to great simplicity, thus [drawing] If we have four simple relations abcd & join them thus a b c d to make nine judgements of a simple ab bc cd abc bcd character the others remain ac ad bd abd acd

Nov 14. Deduction may be reduced to the inference of A (informative) Induction to the inference of E (connotative) Hypothesis to the inference of T (denotative) and thus the whole of logic is developable from the disfunction of substantial form, matter, and accident.

Nov. 14 The doctrine of immortality which makes man last forever is not so enabling as [that, crossed out] [its, crossed out] contrary which must make man's interest out run himself, in time as well as space. Do you say that man lives in all time? I will match all four arguments by others to show that he lives in all space.

Last edit over 1 year ago by Alliteration
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Nov 15

A fallacy is a miracle. I cannot admit its existence as a violation of logical law. A fallacy is a reasoning from mistaken data. That is 1st from insuffient data or from a fallacious inference or 2nd from using as data something different from what appears to be used. Thus for example if I say for fun: It either rains or it doesn't rain It doesn't rain It rains This conclusion is not reached directly from the premises [not clear] here but from certain emotional premises relating to fun

Nov 15

The common sense doctrine is to be held as far as this goes, that there are no fallacies.

Last edit about 1 year ago by afoutouh
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Scepticism may doubt every thing in particular much it must not lay down any rule of doubt for therein it ceases to be scpticism. Dec 13 It is necessary to reduce all our actions to logical processes so that to do anything is but to take another step in the chain of inference. Thus only can we effect that complete reciprocity between thought & its object which in Rant's Copernican step to announce. Dec 13 The Scotch philosophers need to tell us that there is no present plan in favor of the results of Common Sense.

Last edit about 1 year ago by edwardjohn
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