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Ideas for 'works', 'On the Syllogism IV' and 'fragments/reports'

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5 ideas

5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Epicurus rejected excluded middle, because accepting it for events is fatalistic [Epicurus, by Cicero]
     Full Idea: Epicurus said that not every proposition is either true or false. ...Epicurus was afraid that if he admits that every proposition is true or false he will also have to admit that all events are caused by fate (if they are so from all eternity).
     From: report of Epicurus (fragments/reports [c.289 BCE]) by M. Tullius Cicero - On Fate ('De fato') 10.21
     A reaction: Epicurus proposed his 'swerve' in the movements of atoms to avoid this fatalism. Epicurus is agreeing with Aristotle, who did not accept excluded middle for a future contingent sea-fight.
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
For Aristotle, the subject-predicate structure of Greek reflected a substance-accident structure of reality [Aristotle, by O'Grady]
     Full Idea: Aristotle apparently believed that the subject-predicate structure of Greek reflected the substance-accident nature of reality.
     From: report of Aristotle (works [c.330 BCE]) by Paul O'Grady - Relativism Ch.4
     A reaction: We need not assume that Aristotle is wrong. It is a chicken-and-egg. There is something obvious about subject-predicate language, if one assumes that unified objects are part of nature, and not just conventional.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / e. or
Epicureans say disjunctions can be true whiile the disjuncts are not true [Epicurus, by Cicero]
     Full Idea: Epicureans make the impudent assertion that disjunctions consisting of contrary propositions are true, but that the statements contained in the propositions are neither of them true.
     From: report of Epicurus (fragments/reports [c.289 BCE]) by M. Tullius Cicero - On Fate ('De fato') 16.36
     A reaction: Is that 'it is definitely one or the other, but we haven't a clue which one'? Seems to fit speculations about Goldbach's Conjecture. It doesn't sound terribly impudent to me. Or is it the crazy 'It's definitely one of them, but it's neither of them'?
5. Theory of Logic / E. Structures of Logic / 6. Relations in Logic
De Morgan started the study of relations and their properties [De Morgan, by Walicki]
     Full Idea: De Morgan started the sustained interest in the study of relations and their properties.
     From: report of Augustus De Morgan (On the Syllogism IV [1859]) by Michal Walicki - Introduction to Mathematical Logic History D.1.1
De Morgan found inferences involving relations, which eluded Aristotle's syllogistic [De Morgan, by Hart,WD]
     Full Idea: There was a prejudice against relations (in favour of properties) but De Morgan and others that impeccable inferences turn on relations and elude Aristotle's syllogistic. Thus: All horses are animals. Hence, all heads of horses are heads of animals.
     From: report of Augustus De Morgan (On the Syllogism IV [1859]) by William D. Hart - The Evolution of Logic 4
     A reaction: This is actually an early example of modern analytic philosophy in action. You start with the inferences, and then work back to the ontology and the definition of concepts. But in pinning down such concepts, do we miss their full meaning?