13 ideas
10163 | Propositional modal logic has been proved to be complete [Kripke, by Feferman/Feferman] |
Full Idea: At the age of 19 Saul Kripke published a completeness proof of propositional modal logic. | |
From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Feferman / Feferman - Alfred Tarski: life and logic Int V |
10760 | With possible worlds, S4 and S5 are sound and complete, but S1-S3 are not even sound [Kripke, by Rossberg] |
Full Idea: Kripke gave a possible worlds semantics to a whole range of modal logics, and S4 and S5 turned out to be both sound and complete with this semantics. Hence more systems could be designed. S1-S3 failed in soundness, leading to 'impossible worlds'. | |
From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Marcus Rossberg - First-order Logic, 2nd-order, Completeness §4 |
16189 | The variable domain approach to quantified modal logic invalidates the Barcan Formula [Kripke, by Simchen] |
Full Idea: Kripke's variable domain approach to quantified modal logic famously invalidates the Barcan Formula. | |
From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Ori Simchen - The Barcan Formula and Metaphysics §3 | |
A reaction: [p.9 and p.16] In a single combined domain all the possibilia must be present, but with variable domains objects in remote domains may not exist in your local domain. BF is committed to those possible objects. |
15132 | The Barcan formulas fail in models with varying domains [Kripke, by Williamson] |
Full Idea: Kripke showed that the Barcan formula ∀x□A⊃□∀xA and its converse fail in models which require varying domains. | |
From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Timothy Williamson - Truthmakers and Converse Barcan Formula §1 | |
A reaction: I think this is why I reject the Barcan formulas for metaphysics - because the domain of metaphysics should be seen as varying, since some objects are possible in some contexts and not in others. Hmm… |
19494 | Fictionalism allows that simulated beliefs may be tracking real facts [Yablo] |
Full Idea: The fictionalist offers the option that your simulated beliefs and assertions may be tracking a realm of genuine facts, or a realm of what you take to be facts. | |
From: Stephen Yablo (Go Figure: a Path through Fictionalism [2001], 13) | |
A reaction: This means that fictionalism does not have to be an error theory. That is, we aren't mistakenly believing something that we actually made up. Instead we are sensibly believing something we know to be not literally true. Love it. |
19493 | Governing possible worlds theory is the fiction that if something is possible, it happens in a world [Yablo] |
Full Idea: The governing fiction of possible worlds theory says that whenever something is possible, there is a world where it happens. | |
From: Stephen Yablo (Go Figure: a Path through Fictionalism [2001], 05) | |
A reaction: This sounds like the only sensible attitude to possible worlds I can think of. |
21833 | Research suggest that we overrate conscious experience [Flanagan] |
Full Idea: The emerging consensus is that we probably overrate the power of conscious experience in our lives. Freud, of course, said the same thing for different reasons. | |
From: Owen Flanagan (The Really Hard Problem [2007], 3 'Ontology') | |
A reaction: [He cites Pockett, Banks and Gallagher 2006]. Freud was concerned with big deep secrets, but the modern view concerns ordinary decisions and perceptions. An important idea, which should incline us all to become Nietzscheans. |
21834 | Sensations may be identical to brain events, but complex mental events don't seem to be [Flanagan] |
Full Idea: There is still some hope for something like identity theory for sensations. But almost no one believes that strict identity theory will work for more complex mental states. Strict identity is stronger than type neurophysicalism. | |
From: Owen Flanagan (The Really Hard Problem [2007], 3 'Ontology') | |
A reaction: It is so hard to express the problem. What needs to be explained? How can one bunch of neurons represent many different things? It's not like computing. That just transfers the data to brains, where the puzzling stuff happens. |
21837 | Morality is normative because it identifies best practices among the normal practices [Flanagan] |
Full Idea: Morality is 'normative' in the sense that it consists of the extraction of ''good' or 'excellent' practices from common practices. | |
From: Owen Flanagan (The Really Hard Problem [2007], 4 'Naturalism') |
21830 | For Darwinians, altruism is either contracts or genetics [Flanagan] |
Full Idea: Two explanations came forward in the neo-Darwinian synthesis. Altruism is either 1) person-based reciprocal altruism, or 2) gene-based kin altruism. | |
From: Owen Flanagan (The Really Hard Problem [2007], 2 'Darwin') | |
A reaction: Flanagan obviously thinks there is also 'genuine psychological atruism'. Presumably we don't explain mathematics or music or the desire to travel as either contracts or genetics, so we have other explanations available. |
21835 | We need Eudaimonics - the empirical study of how we should flourish [Flanagan] |
Full Idea: It would be nice if I could advance the case for Eudaimonics - empirical enquiry into the nature, causes, and constituents of flourishing, …and the case for some ways of living and being as better than others. | |
From: Owen Flanagan (The Really Hard Problem [2007], 4 'Normative') | |
A reaction: Things seem to be moving in that direction. Lots of statistics about happiness have been appearing. |
21831 | Alienation is not finding what one wants, or being unable to achieve it [Flanagan] |
Full Idea: What Marx called 'alienation' is the widespread condition of not being able to discover what one wants, or not being remotely positioned to achieve. | |
From: Owen Flanagan (The Really Hard Problem [2007], 2 'Expanding') | |
A reaction: I took alienation to concern people's relationship to the means of production in their trade. On Flanagan's definition I would expect almost everyone aged under 20 to count as alienated. |
21832 | Buddhists reject God and the self, and accept suffering as key, and liberation through wisdom [Flanagan] |
Full Idea: Buddhism rejected the idea of a creator God, and the unchanging self [atman]. They accept the appearance-reality distinction, reward for virtue [karma], suffering defining our predicament, and that liberation [nirvana] is possible through wisdom. | |
From: Owen Flanagan (The Really Hard Problem [2007], 3 'Buddhism') | |
A reaction: [Compressed] Flanagan is an analytic philosopher and a practising Buddhist. Looking at a happiness map today which shows Europeans largely happy, and Africans largely miserable, I can see why they thought suffering was basic. |