Coordinates of Thought: topics
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The sea battle argument is a scope mistake, and Aristotle half saw it
Chapter 9 of De Interpretatione makes a fatalist of somebody in my class every year. So here is the case I make to them, and I would like it attacked by people who know more logic than my students. The argument: if…
Started by Giulia Ferrante4 replies -
Natural law is a form of ethical naturalism, and it needs no ontological naturalism
I keep meeting a confusion, in students and in some books: that "naturalism" is one view, and that a Catholic, by definition, can't be a naturalist. My thesis: natural law theory is a form of ethical naturalism, because it holds that moral…
Started by Ikechukwu Anyanwu4 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 -
Unrestricted composition is the only principled answer to when parts make a whole
Thesis: any things whatever compose something. Here is why I think universalism is the only principled position. Restriction generates vagueness. If only some collections compose, there will be a sequence of cases, removing one particle at a time, in which composition goes…
Started by Derek Hollis6 replies -
Robert Adams’s modified divine command theory answers the ‘God could command cruelty’ objection
The standing objection to divine command theory is that if obligation depends on God's will as such, the content of morality could in principle have been anything. Had God commanded gratuitous cruelty, cruelty would have been obligatory. William of Ockham is often…
Started by Aoife Kilbride5 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 -
Traditions that disagree about the self agree about how to live, so ethics can do without metaphysics
There is one comparison that always woke my students up. Put the great traditions side by side on what a person is, and they disagree completely: an immortal soul, an eternal self identical with the absolute, no abiding self at all, a…
Started by Henrike Vogel6 replies -
Reading group: Sen’s ‘Rational Fools’ and the problem of commitment
Amartya Sen's essay "Rational Fools: A Critique of the Behavioural Foundations of Economic Theory" appeared in Philosophy & Public Affairs in 1977 and is reprinted in his Choice, Welfare and Measurement. It's about thirty pages and it has been rattling around my…
Started by Derek Hollis5 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 -
Metaphysics is about what grounds what, not about what exists
For most of the last century analytic metaphysics followed Quine: the job of ontology is to say what exists, and existence is settled by what our best theories quantify over. Recently a neo-Aristotelian movement has pushed back. Jonathan Schaffer put it bluntly…
Started by Ikechukwu Anyanwu5 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 -
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 -
Fuzzy logic is good engineering and a poor theory of vagueness
I've shipped fuzzy controllers. They work, they're cheap, and nobody who has used a decent one doubts that. My thesis is narrower: as an account of what vague words mean, fuzzy logic doesn't solve the problem it's usually advertised as solving. Two…
Started by Derek Hollis4 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 -
Reading group: David Lewis, On the Plurality of Worlds (1986), chapters 1–4
Most people meet modal realism as a punchline: the man who believed every possible world is as real as ours. I want to read the book properly, because the argument is far better than its reputation, and because I think most of…
Started by Tomasz Szewczak6 replies -
Reading group: Pascal’s wager fragment and the pages around it, in French and English
I translate for a living, and Pascal is one of the writers whose sentences I envy most. The wager is usually taught as a three-line argument in a table. In the Pensées it is a long, broken, urgent fragment, and the context…
Started by Claire Dubois6 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 -
An infinite chain of reasons is not a defect: the case for infinitism deserves more than a smirk
When students first meet the regress problem they are told there are three options and one of them is obviously absurd. Foundations, coherence, or an infinite regress; and who could believe in an infinite regress? I want to argue that infinitism, defended…
Started by Tomasz Szewczak5 replies -
Reading group: Tarski’s “The Semantic Conception of Truth” (1944) in three sittings
Tarski's technical work on truth is hard going, but in 1944 he wrote a non-technical paper for Philosophy and Phenomenological Research that explains the ideas for philosophers. It is clear, polemical in places, and only thirty-odd pages. I propose we read it…
Started by Tomasz Szewczak6 replies -
Reading group: Quine’s ‘On What There Is’, slowly, in three sittings
"On What There Is" first appeared in the Review of Metaphysics in 1948 and opens From a Logical Point of View (1953). It is short, funny in places, and much quoted by people who have not read it. I propose we read…
Started by Tomasz Szewczak6 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 -
Reading group: Nagel’s bat, Chalmers’s hard problem and Dennett’s case against qualia
I write formal-verification tools for a living, and I like threads where the argument can be pinned down. Consciousness is the place where that's hardest, so let's read three short classics together, in the order that shows the debate developing. Week 1.…
Started by Derek Hollis5 replies