structure for 'Formal Logic'    |     alphabetical list of themes    |     expand these ideas

4. Formal Logic / A. Syllogistic Logic / 1. Aristotelian Logic

[Aristotle's original account of formal syllogistic logic]

11 ideas
Square of Opposition: not both true, or not both false; one-way implication; opposite truth-values [Aristotle]
Aristotelian syllogisms are three-part, subject-predicate, existentially committed, with laws of thought [Hanna on Aristotle]
Aristotelian identified 256 possible syllogisms, saying that 19 are valid [Devlin on Aristotle]
Aristotle listed nineteen valid syllogisms (though a few of them were wrong) [Devlin on Aristotle]
Modern notation frees us from Aristotle's restriction of only using two class-names in premises [Putnam]
Aristotelian logic is complete [Shapiro]
Syllogistic logic has one rule: what is affirmed/denied of wholes is affirmed/denied of their parts [Engelbretsen/Sayward]
Aristotle replace Plato's noun-verb form with unions of pairs of terms by one of four 'copulae' [Engelbretsen/Sayward]
The four 'perfect syllogisms' are called Barbara, Celarent, Darii and Ferio [Engelbretsen/Sayward]
Traditional term logic struggled to express relations [Engelbretsen]
Aristotelian sentences are made up by one of four 'formative' connectors [Engelbretsen]