Questions tagged [medieval-logic]

6 questions
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How do I use the "Barbara, Celarent, … etc." mnemonic?

Medieval logicians memorized this most famous logic mnemonic: Barbara, Celarent, Darii, Ferio ← direct first figure Baralipton, Celantes, Dabitis, Fapesmo, Frisesomorum ← indirect first figure Cesare, Camestres, Festino, Baroco ← second…
Geremia
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Did William of Soissons prove the law of explosion in the 12th century?

In the 12th century, William of Soissons attempted to prove that any proposition can be inferred from a contradiction. I've adapted his proof into a logical system I'm more familiar with: Let E represent any given proposition P ^ ~P, Premise P,…
N. Bar
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How do medieval theories of reference account for *entia rationis* (objects of thought)?

The medieval theories of logic generally hold, at least as represented in the brilliant work of Thomas Aquinas, that non-existent being can be said of existent being because non-existent being can be said to exist in some ontologically distinct…
Bombadil
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Are analogical middle terms sufficient for a valid demonstration?

William A. Wallace, O.P., in “Thomism and the Quantum Enigma,” The Thomist 61 (1997): 455–468, claims that analogical middle terms are sufficient for a valid demonstration and that this is a teaching that is distinctive of Thomism that other…
Geremia
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Where does Aquinas get his "logical-metaphysical presuppositions"?

In the Summa, Aquinas frequently invokes (for lack of a better term) certain "logical-metaphysical presuppositions." Here are two examples drawn from I-II, qq. 90-91: "that which is the principle in any genus, is the rule and measure of that…
Doubt
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"Animal is human": human is not among the five predicables

I'm asking about the proposition "Animal is human" (as opposed to "Human is an animal"). All predicates are amongst the five predicables, i.e. they are either essential or accidental to the subject. Here, human is neither essential nor accidental to…
Shahram
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