48 ideas
| 22285 | Impredicative definitions are circular, but fine for picking out, rather than creating something [Potter] |
| Full Idea: The circularity in a definition where the property being defined is used in the definition is now known as 'impredicativity'. ...Some cases ('the tallest man in the room') are unproblematic, as they pick him out, and don't conjure him into existence. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 07 'Impred') | |
| A reaction: [part summary] |
| 22301 | The Identity Theory says a proposition is true if it coincides with what makes it true [Potter] |
| Full Idea: The Identity Theory of truth says a proposition is true just in case it coincides with what makes it true. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 23 'Abs') | |
| A reaction: The obvious question is how 'there are trees in the wood' can somehow 'coincide with' or 'be identical to' the situation outside my window. The theory is sort of right, but we will never define the relationship, which is no better than 'corresponds'. |
| 22324 | It has been unfortunate that externalism about truth is equated with correspondence [Potter] |
| Full Idea: There has been an unfortunate tendency in the secondary literature to equate externalism about truth with the correspondence theory. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 65 'Truth') | |
| A reaction: Quite helpful to distinguish internalist from externalist theories of truth. It is certainly the case that robust externalist views of truth have unfortunately been discredited merely because the correspondence account is inadequate. |
| 3593 | The only way to specify the corresponding fact is asserting the sentence [Williams,M] |
| Full Idea: The trouble with appeal to facts in the correspondence theory is that, in general, we have no way of indicating what fact a sentence, when true, corresponds to other than asserting the sentence. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.12) |
| 3584 | Justification needs coherence, while truth might be ideal coherence [Williams,M] |
| Full Idea: Contemporary coherence theorists are advancing a theory of justification, not of truth, …with those who argue that truth is also coherence explaining it in terms of ideal coherence, or coherence at the limit of enquiry. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.10) |
| 3585 | Coherence needs positive links, not just absence of conflict [Williams,M] |
| Full Idea: It is often claimed that coherence is more than 'absence of conflict' between beliefs; it also involves 'positive connections'. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.10) |
| 3599 | Deduction shows entailments, not what to believe [Williams,M] |
| Full Idea: The rules of deduction are rules of entailment, not rules of inference. They tell us what follows from what, not what to believe on the basis of what. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.18) |
| 22279 | Frege's sign |--- meant judgements, but the modern |- turnstile means inference, with intecedents [Potter] |
| Full Idea: Natural deduction systems generally depend on conditional proof, but for Frege everything is asserted unconditionally. The modern turnstile |- is allowed to have antecedents, and hence to represent inference rather than Frege's judgement sign |---. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 03 'Axioms') | |
| A reaction: [compressed] Shockingly, Frege's approach seems more psychological than the modern approach. I would say that the whole point of logic is that it has to be conditional, because the truth of the antecedents is irrelevant. |
| 22291 | Deductivism can't explain how the world supports unconditional conclusions [Potter] |
| Full Idea: Deductivism is a good account of large parts of mathematics, but stumbles where mathematics is directly applicable to the world. It fails to explain how we detach the antecedent so as to arrive at unconditional conclusions. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 12 'Deduc') | |
| A reaction: I suppose the reply would be that we have designed deductive structures which fit our understanding of reality - so it is all deductive, but selected pragmatically. |
| 22295 | Modern logical truths are true under all interpretations of the non-logical words [Potter] |
| Full Idea: In the modern definition, a 'logical truth' is true under every interpretation of the non-logical words it contains. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 19 'Frege's') | |
| A reaction: What if the non-logical words are nonsense, or are used inconsistently ('good'), or ambiguously ('bank'), or vaguely ('bald'), or with unsure reference ('the greatest philosopher' becomes 'Bentham')? What qualifies as an 'interpretation'? |
| 22310 | The formalist defence against Gödel is to reject his metalinguistic concept of truth [Potter] |
| Full Idea: Gödel's theorem does not refute formalism outright, because the committed formalist need not recognise the metalinguistic notion of truth to which the theorem appeals. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 45 'Log') | |
| A reaction: The theorem was prior to Tarski's account of truth. Potter says Gödel avoided explicit mention of truth because of this problem. In general Gödel showed that there are truths outside the formal system (which is all provable). |
| 22298 | Why is fictional arithmetic applicable to the real world? [Potter] |
| Full Idea: Fictionalists struggle to explain why arithmetic is applicable to the real world in a way that other stories are not. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 21 'Math') | |
| A reaction: We know why some novels are realistic and others just the opposite. If a novel aimed to 'model' the real world it would be even closer to it. Fictionalists must explain why some fictions are useful. |
| 22287 | If 'concrete' is the negative of 'abstract', that means desires and hallucinations are concrete [Potter] |
| Full Idea: The word 'concrete' is often used as the negative of 'abstract', with the slightly odd consequence that desires and hallucinations are thereby classified as concrete. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 12 'Numb') | |
| A reaction: There is also the even more baffling usage of 'abstract' for the most highly generalised mathematics, leaving lower levels as 'concrete'. I favour the use of 'generalised' wherever possible, rather than 'abstract'. |
| 22284 | 'Greater than', which is the ancestral of 'successor', strictly orders the natural numbers [Potter] |
| Full Idea: From the successor function we can deduce its ancestral, the 'greater than' relation, which is a strict total ordering of the natural numbers. (Frege did not mention this, but Dedekind worked it out, when expounding definition by recursion). | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 07 'Def') | |
| A reaction: [compressed] |
| 22281 | A material conditional cannot capture counterfactual reasoning [Potter] |
| Full Idea: What the material conditional most significantly fails to capture is counterfactual reasoning. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 04 'Sem') | |
| A reaction: The point is that counterfactuals say 'if P were the case (which it isn't), then Q'. But that means P is false, and in the material conditional everything follows from a falsehood. A reinterpretation of the conditional might embrace counterfactuals. |
| 3591 | We could never pin down how many beliefs we have [Williams,M] |
| Full Idea: Asking how many beliefs I have is like asking how many drops of water there are in a bucket. If I believe my dog is in the garden, do I also believe he is not in the house, or in Siberia? | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.11) |
| 3582 | Propositions make error possible, so basic experiential knowledge is impossible [Williams,M] |
| Full Idea: Propositional content is inseparable from possible error. Therefore no judgement, however modest, is indubitable. So if basic experiential knowledge has to be indubitable, there is no such knowledge. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 8) |
| 3592 | Phenomenalism is a form of idealism [Williams,M] |
| Full Idea: Phenomenalism is a form of idealism. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.12) |
| 3579 | Sense data avoid the danger of misrepresenting the world [Williams,M] |
| Full Idea: The point of insisting on the absolute immediacy of sense data is that representation always seems to involve the possibility of misrepresentation. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 8) |
| 3581 | Sense data can't give us knowledge if they are non-propositional [Williams,M] |
| Full Idea: Acquaintance with sense data is supposed to be a form of non-propositional knowledge, but how can something be non-propositional and yet knowledge? | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 8) |
| 3564 | Is it people who are justified, or propositions? [Williams,M] |
| Full Idea: What exactly is supposed to be 'justified': a person's believing some particular proposition, or the proposition that he believes? | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 1) | |
| A reaction: A key distinction. See my comment on Idea 3752. What would justify a sign saying 'treasure buried here'? People can be justified in believing falsehoods. How could a false proposition be justified? |
| 3595 | What works always takes precedence over theories [Williams,M] |
| Full Idea: A theory that represents working practices as unworkable is a bad theory. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.13) | |
| A reaction: Good point. There's a lot of this about in epistemology, especially accusations of circularity or infinite regress, which (if true) don't somehow seem to worry the cove on the Clapham omnibus. |
| 3580 | Experience must be meaningful to act as foundations [Williams,M] |
| Full Idea: If we are to treat experience as the foundation of knowledge, then experience must itself be understood to involve propositional content. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 8) | |
| A reaction: This sounds right, but since pure 'experience' obviously doesn't have propositional content, because it needs interpretation and evaluation, then this strategy won't work. |
| 3578 | Are empirical foundations judgements or experiences? [Williams,M] |
| Full Idea: Empirical foundationists must decide whether knowledge ultimately rests on either beliefs or judgements about experience, or on the experiences or sensations themselves. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 8) | |
| A reaction: This clarifies the key issue very nicely, and I firmly vote for the former option. The simplest point is that error is possible about what sensations are taken to be of, so they won't do on their own. |
| 3576 | Foundationalists are torn between adequacy and security [Williams,M] |
| Full Idea: The foundationalists dilemma is to define a basis for knowledge modest enough to be secure but rich enough to be adequate. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 7) | |
| A reaction: ..And that is just what they are unable to do, precisely because adequate support would have to have enough content to be defeasibe or fallible. |
| 3577 | Strong justification eliminates error, but also reduces our true beliefs [Williams,M] |
| Full Idea: A strongly justificationist view of rationality may not be so rational; we want the truth, but avoiding all errors and maximising our number of true beliefs are not the same thing. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 7) | |
| A reaction: An interesting dilemma - to avoid all errors, believing nothing; to maximise true belief, believe everything. It is rational to follow intuition, guesses, and a wing and a prayer - once you are experienced and educated. |
| 3589 | Why should diverse parts of our knowledge be connected? [Williams,M] |
| Full Idea: Why should political theory ever have much to do with quantum physics, or pet care with parliamentary history? | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.11) | |
| A reaction: This hardly demolishes the coherence account of justification, since your views on pet care had better be coherent, for your pet's sake. It's a pity people can make their politics cohere with their ethics. |
| 3590 | Coherence theory must give a foundational status to coherence itself [Williams,M] |
| Full Idea: Coherence theory implicitly assigns the criteria of coherence a special status. …In so far as this status is assigned a priori, the coherence theory represents a rationalistic variant of foundationalism. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.11) | |
| A reaction: Nice move, to accuse coherence theorists of foundationalism! Wrong, though, because the a priori principles of coherence are not basic beliefs, but evolved pragmatic procedures (or something...). |
| 3571 | Externalism does not require knowing that you know [Williams,M] |
| Full Idea: From an externalist point of view, knowing about one's reliability is not required for 'first-order' knowledge. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 2) | |
| A reaction: Ah. 'First-order knowledge' - what's that? What we used to call 'true belief', I would say. Adequate for animals, and a good guide to daily life, but uncritical and unjustifiable. |
| 3574 | Externalism ignores the social aspect of knowledge [Williams,M] |
| Full Idea: A problem with pure externalism is that it ignores the social dimension of knowledge. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 2) | |
| A reaction: This seems to be contradicted by Idea 3573, which allows a social dimension to agreement over what is reliable. I am inclined to take knowledge as an entirely social concept. |
| 3569 | In the causal theory of knowledge the facts must cause the belief [Williams,M] |
| Full Idea: According to Goldman's early causal theory of knowledge, my belief that p counts as knowledge if and only if it is caused by the fact that p. This is sufficient as well as necessary, and so does not involve justification. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 2) | |
| A reaction: I take his theory simply to be false because what causes a belief is not what justifies it. I expect my mother to ring; the phone rings; I 'know' it is my mother (and it is), because I strongly expect it. |
| 3567 | How could there be causal relations to mathematical facts? [Williams,M] |
| Full Idea: It is not clear what would even be meant by supposing that there are causal relations to mathematical facts. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 2) | |
| A reaction: I agree, though platonists seem to be willing to entertain the possibility that there are causal relations, for which no further explanation can be given. Better is knowledge without a causal relation. |
| 3586 | Only a belief can justify a belief [Williams,M] |
| Full Idea: Justification requires logical rather than causal connections. That is the point of the slogan that only a belief can justify a belief. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.10) | |
| A reaction: It seems better to talk of 'rational' connections, rather than 'logical' connections. It isn't 'logical' to believe that someone despises me because their lip is faintly curled. |
| 3573 | Externalist reliability refers to a range of conventional conditions [Williams,M] |
| Full Idea: The radical externalists' key notion is 'reliability', which is a normative condition governing adequate performance, involving reference to a range of conditions which we decide rather than discover. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 2) | |
| A reaction: If we can decide whether a source is reliable, we can also decide whether a reliable source has performed well on this occasion, and that will always take precedence. |
| 22327 | Knowledge from a drunken schoolteacher is from a reliable and unreliable process [Potter] |
| Full Idea: Knowledge might result from a reliable and an unreliable process. ...Is something knowledge if you were told it by a drunken schoolteacher? | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 66 'Rel') | |
| A reaction: Nice example. The listener must decide which process to rely on. But how do you decide that, if not by assessing the likely truth of what you are being told? It could be a bad teacher who is inspired by drink. |
| 3565 | Sometimes I ought to distrust sources which are actually reliable [Williams,M] |
| Full Idea: I may reach a belief using a procedure that is in fact reliable, but which I ought to distrust. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 1) | |
| A reaction: The tramp on the park bench who gives good share tips. The clock that is finally working, but has been going haywire for weeks. Reliabilism is a bad theory. |
| 3566 | We control our beliefs by virtue of how we enquire [Williams,M] |
| Full Idea: We control our beliefs by virtue of how we enquire. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 1) |
| 3594 | Scepticism just reveals our limited ability to explain things [Williams,M] |
| Full Idea: All the sceptic's arguments show is that there are limits to our capacity to give reasons or cite evidence. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.13) |
| 3575 | Scepticism can involve discrepancy, relativity, infinity, assumption and circularity [Williams,M] |
| Full Idea: The classical Five Modes of Scepticism are Discrepancy (people always disagree), Relativity ('according to you'), Infinity (infinite regress of questions), Assumption (ending in dogma) and Circularity (end up where you started). | |
| From: Michael Williams (Problems of Knowledge [2001], Ch. 5) | |
| A reaction: I take Relativity to be different from scepticism (because, roughly, it says there is nothing to know), and the others go with Agrippa's Trilemma of justification, which may have solutions. |
| 3587 | Seeing electrons in a cloud chamber requires theory [Williams,M] |
| Full Idea: Armed with enough theory, we can see electrons in a cloud chamber. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.10) |
| 22273 | Traditionally there are twelve categories of judgement, in groups of three [Potter] |
| Full Idea: The traditional categorisation of judgements (until at least 1800) was as universal, particular or singular; as affirmative, negative or infinite; as categorical, hypothetical or disjunctive; or as problematic, assertoric or apodictic. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 02 'Trans') | |
| A reaction: Arranging these things in neat groups of three seems to originate with the stoics. Making distinctions like this is very much the job of a philosopher, but arranging them in neat equinumerous groups is intellectual tyranny. |
| 22290 | The phrase 'the concept "horse"' can't refer to a concept, because it is saturated [Potter] |
| Full Idea: Frege's mirroring principle (that the structure of thoughts mirrors that of language) has the uncomfortable consequence that since the phrase 'the concept "horse"' is saturated, it cannot refer to something unsaturated, which includes concepts. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 16 'Conc') |
| 3588 | Foundationalists base meaning in words, coherentists base it in sentences [Williams,M] |
| Full Idea: In the foundationalist picture the meaning of individual words (defined ostensively) is primary, and that of sentences is derivative. For coherentists sentences come first, with meaning understood functionally or inferentially. | |
| From: Michael Williams (Problems of Knowledge [2001], Ch.10) | |
| A reaction: Coherentism about language doesn't imply coherentism about justification. On language I vote for foundationalism, because I am impressed by the phenomenon of compositionality. |
| 22283 | Compositionality should rely on the parsing tree, which may contain more than sentence components [Potter] |
| Full Idea: Compositionality is best seen as saying the semantic value of a string is explained by the strings lower down its parsing tree. It is unimportant whether a string is always parsed in terms of its own substrings. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 05 'Sem') | |
| A reaction: That is, the analysis must explain the meaning, but the analysis can contain more than the actual ingredients of the sentence (which would be too strict). |
| 22282 | 'Direct compositonality' says the components wholly explain a sentence meaning [Potter] |
| Full Idea: Some authors urge the strong notion of 'direct compositionality', which requires that the content of a sentence be explained in terms of the contents of the component parts of that very sentence. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 05 'Sem') | |
| A reaction: The alternative is that meaning is fully explained by an analysis, but that may contain more than the actual components of the sentence. |
| 22296 | Compositionality is more welcome in logic than in linguistics (which is more contextual) [Potter] |
| Full Idea: The principle of compositionality is more popular among philosophers of logic than of language, because the subtle context-sensitivity or ordinary language makes providing a compositional semantics for it a daunting challenge. | |
| From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 21 'Lang') | |
| A reaction: Logicians love breaking complex entities down into simple atomic parts. Linguistics tries to pin down something much more elusive. |
| 7861 | Libet says the processes initiated in the cortex can still be consciously changed [Libet, by Papineau] |
| Full Idea: Libet himself points out that the conscious decisions still have the power to 'endorse' or 'cancel', so to speak, the processes initiated by the earlier cortical activity: no action will result if the action's execution is consciously countermanded. | |
| From: report of Benjamin Libet (Unconscious Cerebral Initiative [1985]) by David Papineau - Thinking about Consciousness 1.4 | |
| A reaction: This is why Libet's findings do not imply 'epiphenomenalism'. It seems that part of a decisive action is non-conscious, undermining the all-or-nothing view of consciousness. Searle tries to smuggle in free will at this point (Idea 3817). |
| 6660 | Libet found conscious choice 0.2 secs before movement, well after unconscious 'readiness potential' [Libet, by Lowe] |
| Full Idea: Libet found that a subject's conscious choice to move was about a fifth of a second before movement, and thus later than the onset of the brain's so-called 'readiness potential', which seems to imply that unconscious processes initiates action. | |
| From: report of Benjamin Libet (Unconscious Cerebral Initiative [1985]) by E.J. Lowe - Introduction to the Philosophy of Mind Ch.9 | |
| A reaction: Of great interest to philosophers! It seems to make conscious choices epiphenomenal. The key move, I think, is to give up the idea of consciousness as being all-or-nothing. My actions are still initiated by 'me', but 'me' shades off into unconsciousness. |