Combining Texts

Ideas for 'works', 'Prior Analytics' and 'The Will to Believe'

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6 ideas

5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
Deduction is when we suppose one thing, and another necessarily follows [Aristotle]
     Full Idea: A deduction is a discourse in which, certain things having been supposed, something different from the things supposed results of necessity because these things are so.
     From: Aristotle (Prior Analytics [c.328 BCE], 24b18)
     A reaction: Notice that it is modal ('suppose', rather than 'know'), that necessity is involved, which is presumably metaphysical necessity, and that there are assumptions about what would be true, and not just what follows from what.
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
Aristotle places terms at opposite ends, joined by a quantified copula [Aristotle, by Sommers]
     Full Idea: Aristotle often preferred to formulate predications by placing the terms at opposite ends of the sentence and joining them by predicating expressions like 'belongs-to-some' or 'belongs-to-every'.
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by Fred Sommers - Intellectual Autobiography 'Conceptions'
     A reaction: This is Sommers's picture of Aristotle, which led Sommers to develop his modern Term Logic.
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 / 7. Predicates in Logic
Aristotle's logic is based on the subject/predicate distinction, which leads him to substances and properties [Aristotle, by Benardete,JA]
     Full Idea: Basic to Aristotle's logic is the grammatical distinction between subject and predicate, which he glosses in terms of the contrast between a substance and its properties.
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by José A. Benardete - Metaphysics: the logical approach Intro
     A reaction: The introduction of quantifiers and 'logical form' can't disguise the fact that we still talk about (and with) objects and predicates, because no one can think of any other way to talk.
5. Theory of Logic / G. Quantification / 1. Quantification
Affirming/denying sentences are universal, particular, or indeterminate [Aristotle]
     Full Idea: Affirming/denying sentences are universal, particular, or indeterminate. Belonging 'to every/to none' is universal; belonging 'to some/not to some/not to every' is particular; belonging or not belonging (without universal/particular) is indeterminate.
     From: Aristotle (Prior Analytics [c.328 BCE], 24a16)
5. Theory of Logic / G. Quantification / 3. Objectual Quantification
Aristotelian logic has two quantifiers of the subject ('all' and 'some') [Aristotle, by Devlin]
     Full Idea: Aristotelian logic has two quantifiers of the subject ('all' and 'some'), and two ways to combine the subject with the predicate ('have', and 'have not'), giving four propositions: all-s-have-p, all-s-have-not-p, some-s-have-p, and some-s-have-not-p.
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by Keith Devlin - Goodbye Descartes Ch.2
     A reaction: Frege seems to have switched from 'some' to 'at-least-one'. Since then other quantifiers have been proposed. See, for example, Ideas 7806 and 6068.