14 ideas
9540 | A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell] |
Full Idea: A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0. | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: In the interpreted version of the logic, 1 and 0 would become T (true) and F (false). The procedure seems to be called nowadays a 'valuation'. |
9541 | The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell] |
Full Idea: The Law of Transposition says that (P→Q) → (¬Q→¬P). | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: That is, if the consequent (Q) of a conditional is false, then the antecedent (P) must have been false. |
9543 | The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell] |
Full Idea: An axiomatic system is most naturally consistent iff no thesis is the negation of another thesis. It can be shown that every axiom is valid, that the transformation rules are validity-preserving, and if a wff α is valid, then ¬α is not valid. | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: [The labels 'soundness' and 'consistency' seem interchangeable here, with the former nowadays preferred] |
9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
Full Idea: To say that an axiom system is 'weakly complete' is to say that every valid wff of the system is derivable as a thesis. ..The system is 'strongly complete' if it cannot have any more theses than it has without falling into inconsistency. | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: [They go on to say that Propositional Logic is strongly complete, but Modal Logic is not] |
19712 | Maybe there is plain 'animal' knowledge, and clearly justified 'reflective' knowledge [Vahid] |
Full Idea: There is a distinction between 'animal knowledge' (which requires only apt belief), and 'reflective knowledge' (requiring both apt and justified belief). | |
From: Hamid Vahid (Externalism/Internalism [2011], 5) | |
A reaction: [He cites Sosa 1991] My inclination (Idea 19711) was to think of knowledge as a continuum (possibly with a contextual component), and this distinction doesn't change my view, though it makes the point. |
19703 | Epistemic is normally marked out from moral or pragmatic justifications by its truth-goal [Vahid] |
Full Idea: It is widely believed that epistemic justification is distinct from other species of justification such as moral or pragmatic justification in that it is intended to serve the so-called 'truth-goal'. | |
From: Hamid Vahid (Externalism/Internalism [2011], 1) | |
A reaction: Kvanvig explicitly argues against this view. He broadens the aims, but it strikes me that other aims are all intertwined with truth in some way, so I find this idea quite plausible. |
19705 | 'Mentalist' internalism seems to miss the main point, if it might not involve an agent's access [Vahid] |
Full Idea: Since mentalism remains neutral on whether mental states need be accessible to an agent ...it does not seem to do justice to the intuitions that drive paradigm internalist positions. | |
From: Hamid Vahid (Externalism/Internalism [2011], 2 A) | |
A reaction: The rival view is 'access internalism', which implies that you can act on and take responsibility for your knowledge, because you are aware of its grounding. If animals know things, that might fit the mentalist picture better. |
19706 | Strong access internalism needs actual awareness; weak versions need possibility of access [Vahid] |
Full Idea: A strong form of 'access internalism' is when an agent is required to be actually aware of the conditions that constitute justification; a weaker version loosens the accessibility condition, requiring only the ability to access the justification. | |
From: Hamid Vahid (Externalism/Internalism [2011], 2 B) | |
A reaction: The super strong version implies that you probably only know one thing at a time, so it must be nonsense. The weaker version has grey areas. I remember roughly the justification, but not the details. The justification is in my diary. Etc. |
19707 | Maybe we need access to our justification, and also to know why it justifies [Vahid] |
Full Idea: Access internalism may also have a truth-conducive conception of justification, where one should not only know what one's reasons are, but also why one's beliefs are probable on one's reasons. | |
From: Hamid Vahid (Externalism/Internalism [2011], 2 B) | |
A reaction: [he cites Bonjour 1985] Sounds reasonable. It would seem odd if you had clear access to the reason, but didn't understand it, because you had just learned it by rote. |
19709 | Internalism in epistemology over-emphasises deliberation about beliefs [Vahid] |
Full Idea: The internalist approach in epistemology seems to suggest an over-inellectualized and deliberative picture of our belief-forming activities. | |
From: Hamid Vahid (Externalism/Internalism [2011], 2.2 B) | |
A reaction: This strikes me as confused. The question is not how do I arrive at my beliefs but what justifies my believing them, and what justifies the beliefs in themselves? My head is full of daft beliefs produced by TV advertising. |
19704 | Externalism may imply that identical mental states might go with different justifications [Vahid] |
Full Idea: According to the 'mentalist' version of internalism, an externalist is someone who maintains that two people can be in the same present mental states while one has a justified belief and the other does not. | |
From: Hamid Vahid (Externalism/Internalism [2011], 2 A) | |
A reaction: It seems an unlikely coincidence, that we have identical mental states, but your is (say) reliably created but mine isn't. Nevertheless this does seem to be an implication of externalism, though not a definition of it. |
19710 | With a counterfactual account of the causal theory, we get knowledge as tracking or sensitive to truth [Vahid] |
Full Idea: The causal theory of justification was soon replaced by Nozick's construal of knowledge as counterfactually sensitive to its truth value (that is, it tracks truth). A counterfactual theory of causation connects this to the causal theory. | |
From: Hamid Vahid (Externalism/Internalism [2011], 3) | |
A reaction: This is presented as an externalist theory, close to the causal theory (and prior to the reliability theory). But how could you be 'sensitive' to a changing truth if the justification was all external? Externally supported beliefs seem ossified. |
19711 | Externalism makes the acquisition of knowledge too easy? [Vahid] |
Full Idea: Internalists say that externalism is inadequate because it makes the obtaining of knowledge and justified beliefs too easy | |
From: Hamid Vahid (Externalism/Internalism [2011], 4) | |
A reaction: This looks like a key issue in epistemology. Do children and animals have lots of knowledge, which they soak up unthinkingly, or do only thinking adults really 'know' things? Why not have degrees of knowledge? |
1556 | By nature people are close to one another, but culture drives them apart [Hippias] |
Full Idea: I regard you all as relatives - by nature, not by convention. By nature like is akin to like, but convention is a tyrant over humankind and often constrains people to act contrary to nature. | |
From: Hippias (fragments/reports [c.430 BCE]), quoted by Plato - Protagoras 337c8 |