Questions tagged [medieval-logic]
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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 ...
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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 ...
- 178
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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 ...
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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 ...
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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 ...
- 7,817
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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,...
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