94 ideas
11300 | Agathon: good [PG] |
Full Idea: Agathon: good, the highest good | |
From: PG (Db (lexicon) [c.1001 BCE], 01) |
11301 | Aisthesis: perception, sensation, consciousness [PG] |
Full Idea: Aisthesis: perception, sensation, consciousness | |
From: PG (Db (lexicon) [c.1001 BCE], 02) |
11302 | Aitia / aition: cause, explanation [PG] |
Full Idea: Aitia / aition: cause, explanation | |
From: PG (Db (lexicon) [c.1001 BCE], 03) | |
A reaction: The consensus is that 'explanation' is the better translation, and hence that the famous Four Causes (in 'Physics') must really be understood as the Four Modes of Explanation. They then make far more sense. |
11303 | Akrasia: lack of control, weakness of will [PG] |
Full Idea: Akrasia: lack of control, weakness of will | |
From: PG (Db (lexicon) [c.1001 BCE], 04) | |
A reaction: The whole Greek debate (and modern debate, I would say) makes much more sense if we stick to 'lack of control' as the translation, and forget about weakness of will - and certainly give up 'incontinence' as a translation. |
11304 | Aletheia: truth [PG] |
Full Idea: Aletheia: truth | |
From: PG (Db (lexicon) [c.1001 BCE], 05) |
11305 | Anamnesis: recollection, remembrance [PG] |
Full Idea: Anamnesis: recollection, remembrance | |
From: PG (Db (lexicon) [c.1001 BCE], 06) | |
A reaction: This is used for Plato's doctrine that we recollect past lives. |
11306 | Ananke: necessity [PG] |
Full Idea: Ananke: necessity | |
From: PG (Db (lexicon) [c.1001 BCE], 07) |
11307 | Antikeimenon: object [PG] |
Full Idea: Antikeimenon: object | |
From: PG (Db (lexicon) [c.1001 BCE], 08) |
11375 | Apatheia: unemotional [PG] |
Full Idea: Apatheia: lack of involvement, unemotional | |
From: PG (Db (lexicon) [c.1001 BCE], 09) |
11308 | Apeiron: the unlimited, indefinite [PG] |
Full Idea: Apeiron: the unlimited, indefinite | |
From: PG (Db (lexicon) [c.1001 BCE], 10) | |
A reaction: Key term in the philosophy of Anaximander, the one unknowable underlying element. |
11376 | Aphairesis: taking away, abstraction [PG] |
Full Idea: Aphairesis: taking away, abstraction | |
From: PG (Db (lexicon) [c.1001 BCE], 11) |
11309 | Apodeixis: demonstration [PG] |
Full Idea: Apodeixis: demonstration, proof | |
From: PG (Db (lexicon) [c.1001 BCE], 12) |
11310 | Aporia: puzzle, question, anomaly [PG] |
Full Idea: Aporia: puzzle, question, anomaly | |
From: PG (Db (lexicon) [c.1001 BCE], 13) |
11311 | Arche: first principle, the basic [PG] |
Full Idea: Arché: first principle, the basic | |
From: PG (Db (lexicon) [c.1001 BCE], 14) | |
A reaction: Interchangeable with 'aitia' by Aristotle. The first principle and the cause are almost identical. |
11312 | Arete: virtue, excellence [PG] |
Full Idea: Areté: virtue, excellence | |
From: PG (Db (lexicon) [c.1001 BCE], 15) | |
A reaction: The word hovers between moral excellence and being good at what you do. Annas defends the older translation as 'virtue', rather than the modern 'excellence'. |
11313 | Chronismos: separation [PG] |
Full Idea: Chronismos: separation | |
From: PG (Db (lexicon) [c.1001 BCE], 16) |
11314 | Diairesis: division [PG] |
Full Idea: Diairesis: division, distinction | |
From: PG (Db (lexicon) [c.1001 BCE], 17) |
11315 | Dialectic: dialectic, discussion [PG] |
Full Idea: Dialectic: dialectic, discussion | |
From: PG (Db (lexicon) [c.1001 BCE], 18) |
11316 | Dianoia: intellection [cf. Noesis] [PG] |
Full Idea: Dianoia: intellection, understanding [cf. Noesis] | |
From: PG (Db (lexicon) [c.1001 BCE], 21) |
11317 | Diaphora: difference [PG] |
Full Idea: Diaphora: difference | |
From: PG (Db (lexicon) [c.1001 BCE], 22) |
11318 | Dikaiosune: moral goodness, justice [PG] |
Full Idea: Dikaiosune: moral goodness, justice | |
From: PG (Db (lexicon) [c.1001 BCE], 23) | |
A reaction: Usually translated as 'justice' in 'Republic', but it is a general term of moral approbation, not like the modern political and legal notion of 'justice'. 'Justice' actually seems to be bad translation. |
11319 | Doxa: opinion, belief [PG] |
Full Idea: Doxa: opinion, belief, judgement | |
From: PG (Db (lexicon) [c.1001 BCE], 24) |
11320 | Dunamis: faculty, potentiality, capacity [PG] |
Full Idea: Dunamis: faculty, potentiality, capacity | |
From: PG (Db (lexicon) [c.1001 BCE], 25) |
11321 | Eidos: form, idea [PG] |
Full Idea: Eidos: form, idea | |
From: PG (Db (lexicon) [c.1001 BCE], 26) | |
A reaction: In Plato it is the word best translated as 'Form' (Theory of...); in Aritotle's 'Categories' it designates the species, and in 'Metaphysics' it ends up naming the structural form of the species (and hence the essence) [Wedin p.120] |
11322 | Elenchos: elenchus, interrogation [PG] |
Full Idea: Elenchos: elenchus, interrogation | |
From: PG (Db (lexicon) [c.1001 BCE], 27) |
11323 | Empeiron: experience [PG] |
Full Idea: Empeiron: experience | |
From: PG (Db (lexicon) [c.1001 BCE], 28) |
11324 | Energeia: employment, actuality, power? [PG] |
Full Idea: Energeia: employment, actuality, power? | |
From: PG (Db (lexicon) [c.1001 BCE], 31) |
11325 | Enkrateia: control [PG] |
Full Idea: Enkrateia: control | |
From: PG (Db (lexicon) [c.1001 BCE], 32) | |
A reaction: See 'akrasia', of which this is the opposite. The enkratic person is controlled. |
11326 | Entelecheia: entelechy, having an end [PG] |
Full Idea: Entelecheia: entelechy, having an end | |
From: PG (Db (lexicon) [c.1001 BCE], 33) |
11327 | Epagoge: induction, explanation [PG] |
Full Idea: Epagoge: induction, explanation, leading on | |
From: PG (Db (lexicon) [c.1001 BCE], 34) |
11328 | Episteme: knowledge, understanding [PG] |
Full Idea: Episteme: knowledge, understanding | |
From: PG (Db (lexicon) [c.1001 BCE], 35) | |
A reaction: Note that 'episteme' can form a plural in Greek, but we can't say 'knowledges', so we have to say 'branches of knowledge', or 'sciences'. |
11329 | Epithumia: appetite [PG] |
Full Idea: Epithumia: appetite | |
From: PG (Db (lexicon) [c.1001 BCE], 36) |
11330 | Ergon: function [PG] |
Full Idea: Ergon: function, work | |
From: PG (Db (lexicon) [c.1001 BCE], 37) |
11331 | Eristic: polemic, disputation [PG] |
Full Idea: Eristic: polemic, disputation | |
From: PG (Db (lexicon) [c.1001 BCE], 38) | |
A reaction: This is confrontational argument, rather than the subtle co-operative dialogue of dialectic. British law courts and the House of Commons are founded on eristic, rather than on dialectic. Could there be a dialectical elected assembly? |
11332 | Eros: love [PG] |
Full Idea: Eros: love, desire | |
From: PG (Db (lexicon) [c.1001 BCE], 41) |
11333 | Eudaimonia: flourishing, happiness, fulfilment [PG] |
Full Idea: Eudaimonia: flourishing, happiness, fulfilment | |
From: PG (Db (lexicon) [c.1001 BCE], 42) | |
A reaction: Some people defend 'happiness' as the translation, but that seems to me wildly misleading, since eudaimonia is something like life going well, and certainly isn't a psychological state - and definitely not pleasure. |
11334 | Genos: type, genus [PG] |
Full Idea: Genos: type, genus, kind | |
From: PG (Db (lexicon) [c.1001 BCE], 43) |
11335 | Hexis: state, habit [PG] |
Full Idea: Hexis: state, habit | |
From: PG (Db (lexicon) [c.1001 BCE], 44) |
11336 | Horismos: definition [PG] |
Full Idea: Horismos: definition | |
From: PG (Db (lexicon) [c.1001 BCE], 45) |
11337 | Hule: matter [PG] |
Full Idea: Hule: matter | |
From: PG (Db (lexicon) [c.1001 BCE], 46) | |
A reaction: The first half of the 'hylomorphism' of Aristotle. See 'morphe'! |
11338 | Hupokeimenon: subject, underlying thing [cf. Tode ti] [PG] |
Full Idea: Hupokeimenon: subject, underlying thing, substratum [cf. Tode ti] | |
From: PG (Db (lexicon) [c.1001 BCE], 47) | |
A reaction: Literally 'that which lies under'. Latin version is 'substratum'. In Aristotle it is the problem, of explaining what lies under. It is not the theory that there is some entity called a 'substratum'. |
11339 | Kalos / kalon: beauty, fineness, nobility [PG] |
Full Idea: Kalos / kalon: beauty, fineness, nobility | |
From: PG (Db (lexicon) [c.1001 BCE], 48) | |
A reaction: A revealing Greek word, which is not only our rather pure notion of 'beauty', but also seems to mean something like wow!, and (very suggestive, this) applies as much to actions as to objects. |
11340 | Kath' hauto: in virtue of itself, essentially [PG] |
Full Idea: Kath' hauto: in virtue of itself, essentially | |
From: PG (Db (lexicon) [c.1001 BCE], 51) |
11341 | Kinesis: movement, process [PG] |
Full Idea: Kinesis: movement, process, change | |
From: PG (Db (lexicon) [c.1001 BCE], 52) |
11342 | Kosmos: order, universe [PG] |
Full Idea: Kosmos: order, universe | |
From: PG (Db (lexicon) [c.1001 BCE], 53) |
11343 | Logos: reason, account, word [PG] |
Full Idea: Logos: reason, account, word | |
From: PG (Db (lexicon) [c.1001 BCE], 54) |
11344 | Meson: the mean [PG] |
Full Idea: Meson: the mean | |
From: PG (Db (lexicon) [c.1001 BCE], 55) | |
A reaction: This is not the 'average', and hence not some theoretical mid-point. I would call it the 'appropriate compromise', remembering that an extreme may be appropriate in certain circumstances. |
11345 | Metechein: partaking, sharing [PG] |
Full Idea: Metechein: partaking, sharing | |
From: PG (Db (lexicon) [c.1001 BCE], 56) | |
A reaction: The key word in Plato for the difficult question of the relationships between the Forms and the particulars. The latter 'partake' of the former. Hm. Compare modern 'instantiation', which strikes me as being equally problematic. |
11377 | Mimesis: imitation, fine art [PG] |
Full Idea: Mimesis: imitation, fine art | |
From: PG (Db (lexicon) [c.1001 BCE], 57) |
11346 | Morphe: form [PG] |
Full Idea: Morphe: form | |
From: PG (Db (lexicon) [c.1001 BCE], 58) |
11347 | Noesis: intellection, rational thought [cf. Dianoia] [PG] |
Full Idea: Noesis: intellection, rational thought [cf. Dianoia] | |
From: PG (Db (lexicon) [c.1001 BCE], 59) |
11348 | Nomos: convention, law, custom [PG] |
Full Idea: Nomos: convention, law, custom | |
From: PG (Db (lexicon) [c.1001 BCE], 61) |
11349 | Nous: intuition, intellect, understanding [PG] |
Full Idea: Nous: intuition, intellect | |
From: PG (Db (lexicon) [c.1001 BCE], 62) | |
A reaction: There is a condensed discussion of 'nous' in Aristotle's Posterior Analytics B.19 |
11350 | Orexis: desire [PG] |
Full Idea: Orexis: desire | |
From: PG (Db (lexicon) [c.1001 BCE], 63) |
11351 | Ousia: substance, (primary) being, [see 'Prote ousia'] [PG] |
Full Idea: Ousia: substance, (primary) being [see 'Prote ousia'] | |
From: PG (Db (lexicon) [c.1001 BCE], 64) | |
A reaction: It is based on the verb 'to be'. Latin therefore translated it as 'essentia' (esse: to be), and we have ended up translating it as 'essence', but this is wrong! 'Being' is the best translation, and 'substance' is OK. It is the problem, not the answer. |
11352 | Pathos: emotion, affection, property [PG] |
Full Idea: Pathos: emotion, affection, property | |
From: PG (Db (lexicon) [c.1001 BCE], 65) |
11353 | Phantasia: imagination [PG] |
Full Idea: Phantasia: imagination | |
From: PG (Db (lexicon) [c.1001 BCE], 66) |
11354 | Philia: friendship [PG] |
Full Idea: Philia: friendship | |
From: PG (Db (lexicon) [c.1001 BCE], 67) |
11355 | Philosophia: philosophy, love of wisdom [PG] |
Full Idea: Philosophia: philosophy, love of wisdom | |
From: PG (Db (lexicon) [c.1001 BCE], 68) | |
A reaction: The point of the word is its claim only to love wisdom, and not actually to be wise. |
11356 | Phronesis: prudence, practical reason, common sense [PG] |
Full Idea: Phronesis: prudence, practical reason, common sense | |
From: PG (Db (lexicon) [c.1001 BCE], 71) | |
A reaction: None of the experts use my own translation, which is 'common sense', but that seems to me to perfectly fit all of Aristotle's discussions of the word in 'Ethics'. 'Prudence' seems a daft translation in modern English. |
11357 | Physis: nature [PG] |
Full Idea: Physis: nature | |
From: PG (Db (lexicon) [c.1001 BCE], 72) |
11358 | Praxis: action, activity [PG] |
Full Idea: Praxis: action, activity | |
From: PG (Db (lexicon) [c.1001 BCE], 73) |
11359 | Prote ousia: primary being [PG] |
Full Idea: Prote ousia: primary being | |
From: PG (Db (lexicon) [c.1001 BCE], 74) | |
A reaction: The main topic of investigation in Aristotle's 'Metaphysics'. 'Ousia' is the central problem of the text, NOT the answer to the problem. |
11360 | Psuche: mind, soul, life [PG] |
Full Idea: Psuche: mind, soul, life | |
From: PG (Db (lexicon) [c.1001 BCE], 75) | |
A reaction: The interesting thing about this is that we have tended to translate it as 'soul', but Aristotle says plants have it, and not merely conscious beings. It is something like the 'form' of a living thing, but then 'form' is a misleading translation too. |
11361 | Sophia: wisdom [PG] |
Full Idea: Sophia: wisdom | |
From: PG (Db (lexicon) [c.1001 BCE], 76) |
11362 | Sophrosune: moderation, self-control [PG] |
Full Idea: Sophrosune: moderation, self-control | |
From: PG (Db (lexicon) [c.1001 BCE], 77) |
11363 | Stoicheia: elements [PG] |
Full Idea: Stoicheia: elements | |
From: PG (Db (lexicon) [c.1001 BCE], 78) |
11364 | Sullogismos: deduction, syllogism [PG] |
Full Idea: Sullogismos: deduction, syllogism | |
From: PG (Db (lexicon) [c.1001 BCE], 81) |
11365 | Techne: skill, practical knowledge [PG] |
Full Idea: Techne: skill, practical knowledge | |
From: PG (Db (lexicon) [c.1001 BCE], 82) |
11366 | Telos: purpose, end [PG] |
Full Idea: Telos: purpose, end | |
From: PG (Db (lexicon) [c.1001 BCE], 83) |
11367 | Theoria: contemplation [PG] |
Full Idea: Theoria: contemplation | |
From: PG (Db (lexicon) [c.1001 BCE], 84) |
11368 | Theos: god [PG] |
Full Idea: Theos: god | |
From: PG (Db (lexicon) [c.1001 BCE], 85) |
11369 | Ti esti: what-something-is, essence [PG] |
Full Idea: Ti esti: the what-something-is, essence, whatness | |
From: PG (Db (lexicon) [c.1001 BCE], 86) |
11370 | Timoria: vengeance, punishment [PG] |
Full Idea: Timoria: vengeance, punishment | |
From: PG (Db (lexicon) [c.1001 BCE], 87) |
11371 | To ti en einai: essence, what-it-is-to-be [PG] |
Full Idea: To ti en einai: essence, what-it-is-to-be | |
From: PG (Db (lexicon) [c.1001 BCE], 88) | |
A reaction: This is Aristotle's main term for what we would now call the 'essence'. It is still not a theory of essence, merely an identification of the target. 'Form' is the nearest we get to his actual theory. |
11372 | To ti estin: essence [PG] |
Full Idea: To ti estin: essence | |
From: PG (Db (lexicon) [c.1001 BCE], 91) |
11373 | Tode ti: this-such, subject of predication [cf. hupokeimenon] [PG] |
Full Idea: Tode ti: this-something, subject of predication, thisness [cf. hupokeimenon] | |
From: PG (Db (lexicon) [c.1001 BCE], 92) |
8952 | We reach 'reflective equilibrium' when intuitions and theory completely align [Fisher] |
Full Idea: A state of 'reflective equilibrium' is when our theory and our intuitions become completely aligned | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.IV) | |
A reaction: [Rawls made this concept famous] This is a helpful concept in trying to spell out the ideal which is the dream of believers in 'pure reason' - that there is a goal in which everything comes right. The problem is when people have different intuitions! |
8943 | Three-valued logic says excluded middle and non-contradition are not tautologies [Fisher] |
Full Idea: In three-valued logic (L3), neither the law of excluded middle (p or not-p), nor the law of non-contradiction (not(p and not-p)) will be tautologies. If p has the value 'indeterminate' then so will not-p. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.I) | |
A reaction: I quite accept that the world is full of indeterminate propositions, and that excluded middle and non-contradiction can sometimes be uncertain, but I am reluctant to accept that what is being offered here should be called 'logic'. |
8945 | Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher] |
Full Idea: In fuzzy logic objects have properties to a greater or lesser degree, and truth values are given as fractions or decimals, ranging from 0 to 1. Not-p is defined as 1-p, and other formula are defined in terms of maxima and minima for sets. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
A reaction: The question seems to be whether this is actually logic, or a recasting of probability theory. Susan Haack attacks it. If logic is the study of how truth is preserved as we move between propositions, then 0 and 1 need a special status. |
14187 | If logic is topic-neutral that means it delves into all subjects, rather than having a pure subject matter [Read] |
Full Idea: The topic-neutrality of logic need not mean there is a pure subject matter for logic; rather, that the logician may need to go everywhere, into mathematics and even into metaphysics. | |
From: Stephen Read (Formal and Material Consequence [1994], 'Logic') |
8951 | Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher] |
Full Idea: For simplicity, we can say that 'classical logic' amounts to the truth of four sentences: 1) either p or not-p; 2) it is not the case that both p and not-p; 3) from p and not-p, infer q; 4) from p or q and not-p, infer q. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.I) | |
A reaction: [She says there are many ways of specifying classical logic] Intuition suggests that 2 and 4 are rather hard to dispute, while 1 is ignoring some grey areas, and 3 is totally ridiculous. There is, of course, plenty of support for 3! |
14183 | Maybe arguments are only valid when suppressed premises are all stated - but why? [Read] |
Full Idea: Maybe some arguments are really only valid when a suppressed premise is made explicit, as when we say that 'taller than' is a transitive concept. ...But what is added by making the hidden premise explicit? It cannot alter the soundness of the argument. | |
From: Stephen Read (Formal and Material Consequence [1994], 'Suppress') |
14188 | Not all arguments are valid because of form; validity is just true premises and false conclusion being impossible [Read] |
Full Idea: Belief that every valid argument is valid in virtue of form is a myth. ..Validity is a question of the impossibility of true premises and false conclusion for whatever reason, and some arguments are materially valid and the reason is not purely logical. | |
From: Stephen Read (Formal and Material Consequence [1994], 'Logic') | |
A reaction: An example of a non-logical reason is the transitive nature of 'taller than'. Conceptual connections are the usual example, as in 'it's red so it is coloured'. This seems to be a defence of the priority of semantic consequence in logic. |
14182 | If the logic of 'taller of' rests just on meaning, then logic may be the study of merely formal consequence [Read] |
Full Idea: In 'A is taller than B, and B is taller than C, so A is taller than C' this can been seen as a matter of meaning - it is part of the meaning of 'taller' that it is transitive, but not of logic. Logic is now seen as the study of formal consequence. | |
From: Stephen Read (Formal and Material Consequence [1994], 'Reduct') | |
A reaction: I think I find this approach quite appealing. Obviously you can reason about taller-than relations, by putting the concepts together like jigsaw pieces, but I tend to think of logic as something which is necessarily implementable on a machine. |
14184 | In modus ponens the 'if-then' premise contributes nothing if the conclusion follows anyway [Read] |
Full Idea: A puzzle about modus ponens is that the major premise is either false or unnecessary: A, If A then B / so B. If the major premise is true, then B follows from A, so the major premise is redundant. So it is false or not needed, and contributes nothing. | |
From: Stephen Read (Formal and Material Consequence [1994], 'Repres') | |
A reaction: Not sure which is the 'major premise' here, but it seems to be saying that the 'if A then B' is redundant. If I say 'it's raining so the grass is wet', it seems pointless to slip in the middle the remark that rain implies wet grass. Good point. |
8950 | Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher] |
Full Idea: Even if one is inclined to be a realist about everything, it is hard to see why our logic should be the determiner. Logic is supposed to formalize how we ought to reason, but whether or not we should be realists is a matter of philosophy, not logic. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 09.I) | |
A reaction: Nice to hear a logician saying this. I do not see why talk in terms of an object is a commitment to its existence. We can discuss the philosopher's stone, or Arthur's sword, or the Loch Ness monster, or gravitinos, with degrees of commitment. |
14186 | Logical connectives contain no information, but just record combination relations between facts [Read] |
Full Idea: The logical connectives are useful for bundling information, that B follows from A, or that one of A or B is true. ..They import no information of their own, but serve to record combinations of other facts. | |
From: Stephen Read (Formal and Material Consequence [1994], 'Repres') | |
A reaction: Anyone who suggests a link between logic and 'facts' gets my vote, so this sounds a promising idea. However, logical truths have a high degree of generality, which seems somehow above the 'facts'. |
8946 | We could make our intuitions about heaps precise with a million-valued logic [Fisher] |
Full Idea: We could construct a 1,000,000-valued logic that would allow our intuitions concerning a heap to vary exactly with the amount of sand in the heap. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008]) | |
A reaction: Presumably only an infinite number of grains of sand would then produce a true heap, and even one grain would count as a bit of a heap, which must both be wrong, so I can't see this helping much. |
8944 | Vagueness can involve components (like baldness), or not (like boredom) [Fisher] |
Full Idea: Vague terms come in at least two different kinds: those whose constituent parts come in discrete packets (bald, rich, red) and those that don't (beauty, boredom, niceness). | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
A reaction: The first group seem to be features of the external world, and the second all occur in the mind. Baldness may be vague, but presumably hairs are (on the whole) not. Nature doesn't care whether someone is actually 'bald' or not. |
8941 | We can't explain 'possibility' in terms of 'possible' worlds [Fisher] |
Full Idea: Explaining 'it is possible that p' by saying p is true in at least one possible world doesn't get me very far. If I don't understand what possibility is, then appealing to possible worlds is not going to do me much good. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 06.III) | |
A reaction: This seems so blatant that I assume friends of possible worlds will have addressed the problem. Note that you will also need to understand 'possible' to define necessity as 'true in all possible worlds'. Necessarily-p is not-possibly-not-p. |
8947 | If all truths are implied by a falsehood, then not-p might imply both q and not-q [Fisher] |
Full Idea: If all truths are implied by a falsehood, then 'if there are no trees in the park then there is no shade' and 'if there are no trees in the park there is plenty of shade' both come out as true. Intuitively, though, the second one is false. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.I) | |
A reaction: The rule that a falsehood implies all truths must be the weakest idea in classical logic, if it actually implies a contradiction. This means we must take an interest in relevance logics. |
14185 | Conditionals are just a shorthand for some proof, leaving out the details [Read] |
Full Idea: Truth enables us to carry various reports around under certain descriptions ('what Iain said') without all the bothersome detail. Similarly, conditionals enable us to transmit a record of proof without its detail. | |
From: Stephen Read (Formal and Material Consequence [1994], 'Repres') | |
A reaction: This is his proposed Redundancy Theory of conditionals. It grows out of the problem with Modus Ponens mentioned in Idea 14184. To say that there is always an implied 'proof' seems a large claim. |
8949 | In relevance logic, conditionals help information to flow from antecedent to consequent [Fisher] |
Full Idea: A good account of relevance logic suggests that a conditional will be true when the flow of information is such that a conditional is the device that helps information to flow from the antecedent to the consequent. | |
From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.III) | |
A reaction: Hm. 'If you are going out, you'll need an umbrella'. This passes on information about 'out', but also brings in new information. 'If you are going out, I'm leaving you'. What flows is an interpretation of the antecedent. Tricky. |