Category
Logic & argument
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Vitaṇḍā is not always illegitimate: a critic with no thesis can still be doing philosophy
There is one problem in Nāgārjuna I have been chewing on for a long time. The Nyāya tradition calls vitaṇḍā illegitimate: one party only attacks and never defends a position, so they risk nothing and cannot be wrong. That seems fair as…
Started by Nima Tsering Gurung7 replies -
Quine was right that even logic could be revised in the light of experience
Be gentle but not too gentle. We read the end of Quine's "Two Dogmas of Empiricism" (1951) in a seminar last week, and I think its most radical claim is correct: no statement is immune to revision, logic included. The picture: our…
Started by Ethan Mercer6 replies -
Reading group: the first book of the Nyāya Sūtra with Vātsyāyana’s commentary
The Nyāya Sūtra, traditionally attributed to Gautama Akṣapāda and dated around the second century CE in its current form, is the root text of the school that made Indian logic and debate into a system. About three centuries later Vātsyāyana wrote the…
Started by Vikram Sethi6 replies -
Keep the losing opinion on the page: what the Talmud could teach an online forum
The more time I spend in online philosophy forums, including this one, the more I think the rabbis solved some problems we keep failing at. Three practices I'd love to see here. Record the minority view. The Mishnah asks why it bothers…
Started by Eliana Halpern6 replies -
Reading group: Toulmin’s The Uses of Argument, starting from the middle
The Toulmin layout (claim, grounds, warrant, backing, qualifier, rebuttal) is on every debate camp handout in the country. Almost nobody has read the book it comes from. Let's fix that. Text. Stephen Toulmin, The Uses of Argument (1958; the Cambridge updated edition…
Started by Sam Ellery6 replies -
Charity is for evaluating arguments, not for reporting what people actually said
I keep running into a problem with the principle of charity. In philosophy the rule is good: before you object, reconstruct the argument in its strongest form. An objection to a weak version proves nothing about the strong one. I accept that.…
Started by Sana Rizvi6 replies -
Reading group: the Nyāya-sūtra on debate, from the sixteen categories to the points of defeat
Several threads here have touched on the Nyāya distinction between vāda, jalpa and vitaṇḍā. I'd like to read the primary text together, since most of us (me included, honestly) know it through summaries. Text. The Nyāya-sūtra attributed to Gautama (Akṣapāda), with Vātsyāyana's…
Started by Meera Kulkarni6 replies -
Reading group: Prior Analytics I.1–7, slowly, with a Nyāya inference on the table
Everyone says Aristotle invented formal logic, and I realise I have never read the Prior Analytics closely in company. So here is a proposal: the first seven chapters of Book I, over five weeks, which is where the whole assertoric system is…
Started by Giulia Ferrante6 replies -
Outside a courtroom, who should carry the burden of proof?
In court the burden of proof is fixed by rules. In a criminal case the prosecution must prove guilt beyond reasonable doubt; in a civil case the claimant must win on the balance of probabilities. Islamic law has a well-known maxim to…
Started by Hamza Qureshi6 replies -
For ordinary speech, Aristotle was right: “All S are P” presupposes there are some S
Modern logic reads "All S are P" as "for anything, if it is S, it is P". If nothing is S, the statement comes out true automatically. So "All the unicorns in my garden are pink" is true, and so is "All…
Started by Oskar Nyberg6 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 -
Logical pluralism is right, for the same reason statistical pluralism is
In data science the old fight between frequentist and Bayesian statistics has mostly cooled into pluralism: each is legitimate, they answer different questions, and a good analyst knows which to use when. I think logic is the same. Carnap said something like…
Started by Wanjiru Njenga5 replies -
Affirming the consequent on a hospital ward
My nephew is a medical student in Cairo, and listening to him describe his ward rounds I've realised that his teachers spend a lot of their time correcting a logical fallacy, and also committing it. A student says: if this patient had…
Started by Omar Ragab5 replies -
Objections first: what the scholastic quaestio could teach a modern seminar
This term I've been reading the Summa Theologiae properly for the first time, article by article, and what has struck me is not the conclusions but the shape. Every article begins with “It seems that…” followed by objections against the position Aquinas…
Started by Aoife Kilbride5 replies -
‘Killing robbers is not killing people’: the Later Mohists on inferences that fail
One passage in the Later Mohist texts seems to me to belong in any discussion of what predicate logic was invented to handle. In the chapter of the Mozi usually called the "Lesser Selection" (Xiaoqu), the Mohists discuss a kind of inference…
Started by Chen Yuting5 replies -
Dignāga cut the Nyāya inference from five members to three. What did the example member become?
I have been translating some passages on Buddhist logic for a seminar in Pune and keep getting stuck on one question. The Nyāya inference for others has five members: thesis, reason, example, application, conclusion ("this hill has fire, because it has smoke,…
Started by Meera Kulkarni5 replies -
Could a culture reason by different logical rules, or is that a colonial myth?
Every year a student in my lycée class asks me some version of this: "Is logic universal, or is it just how Europeans think?" The history makes the question sharp. In the early twentieth century, Lucien Lévy-Bruhl described so-called primitive peoples as…
Started by Khady Sène5 replies -
Reading group: Aristotle’s Metaphysics Gamma on the firmest principle
Several recent threads keep coming back to Aristotle's defence of the principle of non-contradiction, usually second-hand. Let's read it. It's short and much stranger than its reputation. Text: Metaphysics Book Gamma (IV), chapters 3 to 7. Ross's translation is freely available; Christopher…
Started by Nikos Theodoridis5 replies -
Frege and Husserl started on the same side. What was the psychologism dispute about?
I've been reading about the split between analytic and continental philosophy because my colleagues treat it as two tribes. What surprised me is that both traditions are said to trace back, around 1900, to two men who agreed about something: Frege and…
Started by Pieter van Dijkhuizen5 replies -
Nāgasena’s condition for talking with a king: argue as scholars do, not as kings do
Early in the Milindapañha, the Questions of King Milinda, the king asks the monk Nāgasena to discuss with him. Nāgasena answers with a condition. He will talk if the king will talk as scholars do, not as kings do. What's the difference?…
Started by Nirmala Jayasekara5 replies -
Navya-Nyāya’s language of limitors, and what it was built to do
Every few months someone tells me that Navya-Nyāya was "Indian predicate logic". I'd like to test that claim with people who know Frege better than I do. The school is usually dated from Gaṅgeśa's Tattvacintāmaṇi in the fourteenth century. What Gaṅgeśa and…
Started by Meera Kulkarni5 replies -
Nāgārjuna says he has no thesis. Is “I have no thesis” itself a thesis?
There is a question I keep returning to, the oldest one in the long argument between Advaitins and Mādhyamikas. In the Vigrahavyāvartanī, answering a critic who says his claim that all things are empty refutes itself, Nāgārjuna says (I paraphrase): if I…
Started by Arjun Iyer5 replies -
Logic is the one part of philosophy that settles questions, and the rest should take note
People like to say that philosophy never makes progress, that we're still arguing about the same questions as Plato. Logic is the counterexample. For two thousand years, Aristotle's syllogistic could not handle inferences involving relations. "Every horse is an animal, so every…
Started by Derek Hollis5 replies -
Predicate logic was discovered, not invented
Is logic discovered or invented? I want to argue that predicate logic is the strongest evidence that it is discovered. Consider the inference: every horse is an animal, so every horse's head is an animal's head. People knew for two thousand years…
Started by Tomasz Szewczak5 replies -
Qiyās, kal va-chomer and legal analogy: defeasible reasoning with centuries of rules
The reasoning I heard most often from the bench, in all my years in court, was neither deduction nor statistics. It was analogy: this case resembles that one in the respect that matters, so it should be decided the same way. Islamic…
Started by Khalid Mahmood Awan5 replies -
Reading group: Stoic logic in Diogenes Laertius, Lives Book VII
Chrysippus is said to have written hundreds of books, a large share of them on logic, and almost all are lost. What we have of Stoic logic comes mostly through later writers: Diogenes Laertius, who gives a summary of Stoic dialectic in…
Started by Giulia Ferrante5 replies -
What do the strange names Barbara, Celarent and Darii actually mean?
I'm working through an old logic textbook my uncle left at our house. There is a page with a Latin verse that starts "Barbara, Celarent, Darii, Ferioque..." and then a lot of other names like Cesare and Baroco. The book just says…
Started by Fajar Nugroho4 replies -
Why does logic count ‘if the moon is cheese, then 2 + 2 = 5’ as true?
Half my jokes are conditionals. So I was pleased to find a whole branch of logic about "if". Then I hit the truth table and it broke my brain. Apparently in propositional logic "if P then Q" is false only when P…
Started by Gemma Pritchard4 replies -
Can someone explain what the Nyāya logicians meant by vyāpti (pervasion)?
My training is entirely in Western formal logic, and I've started reading Matilal's The Character of Logic in India. I understand the standard example: there is fire on the hill because there is smoke, and wherever there is smoke there is fire,…
Started by Tomasz Szewczak4 replies -
Nagarjuna’s tetralemma is not a rejection of logic
The catuṣkoṭi, or tetralemma, considers four options for any proposition: it is, it is not, both, neither. In the Mūlamadhyamakakārikā, Nāgārjuna often rejects all four. For example, the Buddha after death neither exists, nor doesn't exist, nor both, nor neither. Some readers…
Started by Meera Kulkarni4 replies