Combining Philosophers

Ideas for Thrasymachus, Aristotle and Lynn Holt

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21 ideas

4. Formal Logic / A. Syllogistic Logic / 1. Aristotelian Logic
Aristotle's later logic had to treat 'Socrates' as 'everything that is Socrates' [Potter on Aristotle]
     Full Idea: When Aristotle moved from basic name+verb (in 'De Interpretatione') to noun+noun logic...names had to be treated as special cases, so that 'Socrates' is treated as short for 'everything that is Socrates'.
     From: comment on Aristotle (On Interpretation [c.330 BCE]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 02 'Supp'
     A reaction: Just the sort of rewriting that Russell introduced for definite descriptions. 'Twas ever the logicians' fate to shoehorn ordinary speech into awkward containers.
Square of Opposition: not both true, or not both false; one-way implication; opposite truth-values [Aristotle]
     Full Idea: Square of Opposition: horizontals - 'contraries' can't both be true, and 'subcontraries' can't both be false; verticals - 'subalternatives' have downwards-only implication; diagonals - 'contradictories' have opposite truth values.
     From: Aristotle (On Interpretation [c.330 BCE], Ch.12-13)
     A reaction: This is still used in modern discussion (e.g. by Stalnaker against Kripke), and there is a modal version of it (Fitting and Mendelsohn p.7). Corners read: 'All F are G', 'No F are G', 'Some F are G' and 'Some F are not G'.
Aristotle was the first to use schematic letters in logic [Aristotle, by Potter]
     Full Idea: It was Aristotle who initiated the use of the letter of the (Greek) alphabet 'schematically', to stand for an unspecified piece of language of some appropriate grammatical type.
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 02 'Aris'
     A reaction: Did he invent it from scratch, or borrow it from the mathematicians? Euclid labels diagrams with letters.
Aristotelian syllogisms are three-part, subject-predicate, existentially committed, with laws of thought [Aristotle, by Hanna]
     Full Idea: Aristotle's logic is based on the triadic syllogism, the distinction between subject and one-place predicates, that universal claims have existential commitment, and bivalence, excluded middle and noncontradiction.
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by Robert Hanna - Rationality and Logic 2.2
Aristotelian sentences are made up by one of four 'formative' connectors [Aristotle, by Engelbretsen]
     Full Idea: For Aristotle there are four formatives for sentences: 'belongs to some', 'belongs to every', 'belongs to no', and 'does not belong to every'. These are 'copulae'. Aristotle would have written 'wise belongs to some man'.
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by George Engelbretsen - Trees, Terms and Truth 3
     A reaction: A rather set-theoretic reading. This invites a Quinean scepticism about whether wisdom is some entity which can 'belong' to a person. It makes trope theory sound attractive, offering a unique wisdom that is integrated into that particular person.
Aristotelian identified 256 possible syllogisms, saying that 19 are valid [Aristotle, by Devlin]
     Full Idea: Aristotle identified four 'figures' of argument, based on combinations of Subject (S) and Predicate (P) and Middle term (M). The addition of 'all' and 'some', and 'has' and 'has not' got the property, resulted in 256 possible syllogisms, 19 of them valid.
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by Keith Devlin - Goodbye Descartes Ch.2
     A reaction: [Compressed version of Devlin] What Aristotle did was astonishing, and must be one of the key ideas of western civilization, even though a lot of his assumptions have been revised or rejected.
Aristotle replaced Plato's noun-verb form with unions of pairs of terms by one of four 'copulae' [Aristotle, by Engelbretsen/Sayward]
     Full Idea: Aristotle replaced the Platonic noun-verb account of logical syntax with a 'copular' account. A sentence is a pair of terms bound together logically (not necessarily grammatically) by one of four 'logical copulae' (every, none, some, not some).
     From: report of Aristotle (Prior Analytics [c.328 BCE]) by Engelbretsen,G/Sayward,C - Philosophical Logic: Intro to Advanced Topics 8
     A reaction: So the four copulas are are-all, are-never, are-sometimes, and are-sometime-not. Consider 'men' and 'mortal'. Alternatively, Idea 18909.
Aristotle listed nineteen valid syllogisms (though a few of them were wrong) [Aristotle, by Devlin]
     Full Idea: Aristotle listed a total of nineteen syllogisms involved in logical reasoning, though some of the ones on his list were subsequently shown to be invalid.
     From: report of Aristotle (Prior Analytics [c.328 BCE], Ch.1) by Keith Devlin - Goodbye Descartes
     A reaction: It is quite upsetting to think that the founding genius got some of it wrong, but that just shows how subtle and complex the analysis of rational thought can be.
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
Aristotle's said some Fs are G or some Fs are not G, forgetting that there might be no Fs [Bostock on Aristotle]
     Full Idea: Aristotle's system accepted as correct some laws which nowadays we reject, for example |= (Some Fs are G) or (some Fs are not G). He failed to take into account the possibility of there being no Fs at all.
     From: comment on Aristotle (Prior Analytics [c.328 BCE]) by David Bostock - Intermediate Logic 8.4
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
An axiom is a principle which must be understood if one is to learn anything [Aristotle]
     Full Idea: An axiom is a principle which must be grasped if anyone is going to learn anything whatever.
     From: Aristotle (Posterior Analytics [c.327 BCE], 72a17)
Axioms are the underlying principles of everything, and who but the philosopher can assess their truth? [Aristotle]
     Full Idea: Axioms are more general, and the principles of all things. If this does not belong to the philosopher, who else will have the job of considering truth and falsity in their case?
     From: Aristotle (Metaphysics [c.324 BCE], 0997a09)
The axioms of mathematics are part of philosophy [Aristotle]
     Full Idea: A single science, that of the philosopher, also covers the axioms of mathematics.
     From: Aristotle (Metaphysics [c.324 BCE], 1005a15)
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
Modal Square 1: □P and ¬◊¬P are 'contraries' of □¬P and ¬◊P [Aristotle, by Fitting/Mendelsohn]
     Full Idea: Modal Square of Opposition 1: 'It is necessary that P' and 'It is not possible that not P' are the contraries (not both true) of 'It is necessary that not P' and 'It is not possible that P'.
     From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12a) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4
Modal Square 2: ¬□¬P and ◊P are 'subcontraries' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn]
     Full Idea: Modal Square of Opposition 2: 'It is not necessary that not P' and 'It is possible that P' are the subcontraries (not both false) of 'It is not necessary that P' and 'It is possible that not P'.
     From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12b) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4
Modal Square 3: □P and ¬◊¬P are 'contradictories' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn]
     Full Idea: Modal Square of Opposition 3: 'It is necessary that P' and 'It is not possible that not P' are the contradictories (different truth values) of 'It is not necessary that P' and 'It is possible that not P'.
     From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12c) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4
Modal Square 4: □¬P and ¬◊P are 'contradictories' of ¬□¬P and ◊P [Aristotle, by Fitting/Mendelsohn]
     Full Idea: Modal Square of Opposition 4: 'It is necessary that not P' and 'It is not possible that P' are the contradictories (different truth values) of 'It is not necessary that not P' and 'It is possible that P'.
     From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12d) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4
Modal Square 5: □P and ¬◊¬P are 'subalternatives' of ¬□¬P and ◊P [Aristotle, by Fitting/Mendelsohn]
     Full Idea: Modal Square of Opposition 5: 'It is necessary that P' and 'It is not possible that not P' are the subalternatives (first implies second) of 'It is not necessary that not P' and 'It is possible that P'.
     From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12e) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4
Modal Square 6: □¬P and ¬◊P are 'subalternatives' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn]
     Full Idea: Modal Square of Opposition 6: 'It is necessary that not P' and 'It is not possible that P' are the subalternatives (first implies second) of 'It is not necessary that P' and 'It is possible that not P'.
     From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12f) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
There are three different deductions for actual terms, necessary terms and possible terms [Aristotle]
     Full Idea: Since to belong, to belong of necessity, and to be possible to belong are different, ..there will be different deductions for each; one deduction will be from necessary terms, one from terms which belong, and one from possible terms.
     From: Aristotle (Prior Analytics [c.328 BCE], 29b29-35)
     A reaction: Fitting and Mendelsohn cite this as the earliest thoughts on modal logic. but Kneale and Kneale say that Aristotle got into a muddle, and so was unable to create a workable system.
4. Formal Logic / G. Formal Mereology / 1. Mereology
Are a part and whole one or many? Either way, what is the cause? [Aristotle]
     Full Idea: There is a difficulty about part and whole, ...whether the part and the whole are one or more than one, and in what way they can be one or many, and, if they are more than one, in what way they are more than one.
     From: Aristotle (Physics [c.337 BCE], 185b11), quoted by Kathrin Koslicki - The Structure of Objects 6.3
     A reaction: He only states the problem here, but doesn't pursue it. I take the real question of mereology to be what makes a many into a one. I don't see a problem with a many being simultaneously a one.
Aristotle relativises the notion of wholeness to different measures [Aristotle, by Koslicki]
     Full Idea: Aristotle proposes to relativise unity and plurality, so that a single object can be both one (indivisible) and many (divisible) simultaneously, without contradiction, relative to different measures. Wholeness has degrees, with the strength of the unity.
     From: report of Aristotle (works [c.330 BCE]) by Kathrin Koslicki - The Structure of Objects 7.2.12
     A reaction: [see Koslicki's account of Aristotle for details] As always, the Aristotelian approach looks by far the most promising. Simplistic mechanical accounts of how parts make wholes aren't going to work. We must include the conventional and conceptual bit.