Format
Question
One question: Explain (can have an accepted answer) or Open (several argued answers)
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Why did the Vaiśeṣikas count direction as a substance?
I teach physics and spend weekends exposing miracle tricks for a rationalist association, so I like the Indian schools that tried to describe the world piece by piece. The Vaiśeṣika list of nine substances is a favourite of mine: earth, water, fire,…
Started by Arvind Poojary3 replies -
Does the dialetheist really believe contradictions, or has she changed the meaning of ‘not’?
A question I keep returning to. Quine, in Philosophy of Logic (1970), has a famous argument against "deviant" logicians. Suppose someone claims to accept a sentence of the form "P and not-P". Quine says: then whatever they mean by "not", it isn't…
Started by Tomasz Szewczak4 replies -
Soundness and completeness of a logical system: what exactly is being proved?
I'm stuck on vocabulary, having no formal training in logic. I've read that a logical system can be sound and complete: everything provable is true, and everything true is provable. Fine. But then I read that Gödel proved a completeness theorem in…
Started by Pieter van Dijkhuizen4 replies -
Is “aesthetic experience” one kind of experience, or a label for several unlike things?
Twice last month I lost track of time completely. Once was a late-night proof that came together with a kind of click, everything suddenly fitting. The other was a recording of the Goldberg Variations on a long drive. Both felt, from the…
Started by Derek Hollis4 replies -
Can reason tell right from wrong on its own, or does it need revelation?
In the courts I covered in Lahore, judges applied statutes, precedent and, where the law allowed, the principles of Islamic law. Many times a case was decided correctly by every rule and I went home feeling it had been decided wrongly. I…
Started by Khalid Mahmood Awan6 replies -
If syllogistic logic couldn’t handle relations, why did it last two thousand years?
Working inside predicate logic every day, I'm often reminded how much it can do that the syllogism can't. The textbook example (usually credited to De Morgan) is: all horses are animals, therefore every head of a horse is the head of an…
Started by Derek Hollis6 replies -
Did Epicurus actually make the argument from evil that carries his name?
In my theology seminar the lecturer put up the famous dilemma, "Is God willing to prevent evil but not able? Then he is not omnipotent. Able but not willing? Then he is malevolent...", with "Epicurus" printed under it. A friend in classics…
Started by Aoife Kilbride4 replies -
How did Kripke’s possible worlds turn S4 and S5 from arbitrary axioms into something meaningful?
I've been reading about modal logic for fun. I understand the operators. What I don't understand is the history I keep seeing summarised: C. I. Lewis invented several systems, S1 to S5, with different axioms; nobody could say which was "correct" or…
Started by Pieter van Dijkhuizen4 replies