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13913
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The four 'perfect syllogisms' are called Barbara, Celarent, Darii and Ferio [Engelbretsen/Sayward]
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Full Idea:
There are four 'perfect syllogisms': Barbara (every M is P, every S is M, so every S is P); Celarent (no M is P, every S is M, so no S is P); Darii (every M is P, some S is M, so some S is P); Ferio (no M is P, some S is M, so some S is not P).
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From:
Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8)
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A reaction:
The four names are mnemonics from medieval universities.
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13916
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Term logic uses expression letters and brackets, and '-' for negative terms, and '+' for compound terms [Engelbretsen/Sayward]
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Full Idea:
Term logic begins with expressions and two 'term functors'. Any simple letter is a 'term', any term prefixed by a minus ('-') is a 'negative term', and any pair of terms flanking a plus ('+') is a 'compound term'. Parenthese are used for grouping.
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From:
Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8)
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A reaction:
[see Engelbretsen and Sayward for the full formal system]
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13849
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Classical logic rests on truth and models, where constructivist logic rests on defence and refutation [Engelbretsen/Sayward]
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Full Idea:
Classical logic rests on the concepts of truth and falsity (and usually makes use of a semantic theory based on models), whereas constructivist logic accounts for inference in terms of defense and refutation.
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From:
Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], Intro)
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A reaction:
My instincts go with the classical view, which is that inferences do not depend on the human capacity to defend them, but sit there awaiting revelation. My view isn't platonist, because I take the inferences to be rooted in the physical world.
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4125
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Hare says I acquire an agglomeration of preferences by role-reversal, leading to utilitarianism [Hare, by Williams,B]
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Full Idea:
In Hare's theory I apply a "role-reversal test", and then acquire an actual agglomeration of preferences that apply to the hypothetical situation. The result is utilitarianism.
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From:
report of Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981]) by Bernard Williams - Ethics and the Limits of Philosophy Ch.5
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A reaction:
It hits that traditional stumbling block, of why I should care about the preferences of others. Pure reason and empathy are the options (Kant or Hume). I may, however, lack both.
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4126
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If we have to want the preferences of the many, we have to abandon our own deeply-held views [Williams,B on Hare]
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Full Idea:
Hare's version of utilitarianism requires an agent to abandon any deeply held principle or conviction if a large enough aggregate of contrary preferences, of whatever kind, favours a contrary action.
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From:
comment on Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981]) by Bernard Williams - Ethics and the Limits of Philosophy Ch.5
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A reaction:
This nicely attacks any impersonal moral theory, whether it is based on reason or preferences. But where did my personal ideals come from?
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4127
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If morality is to be built on identification with the preferences of others, I must agree with their errors [Williams,B on Hare]
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Full Idea:
If there is to be total identification with others, then if another's preferences are mistaken, the preferences I imagine myself into are equally mistaken, and if 'identification' is the point, they should remain mistaken.
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From:
comment on Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981]) by Bernard Williams - Ethics and the Limits of Philosophy Ch.5
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A reaction:
Yes. The core of morality must be judgement. Robots can implement universal utilitarian rules, but they could end up promoting persecutions of minorities.
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22483
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A judgement is presciptive if we expect it to be acted on [Hare]
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Full Idea:
We say something prescriptive if and only if, for some act A, some situation S and some person R, if P were to assent (orally) to what we say, and not, in S, do A, he logically must be assenting insincerely.
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From:
Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981], p.21), quoted by Philippa Foot - Does Moral Subjectivism Rest on a Mistake? p.190
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A reaction:
Foot offers this as Hare's most explicit definition. The use of algebra strikes me as ludicrous. In logic letters have the virtue of not shifting their meaning during an argument, but that is not required here.
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