42 ideas
354 | Wisdom makes virtue and true goodness possible [Plato] |
Full Idea: It is wisdom that makes possible courage and self-control and integrity or, in a word, true goodness. | |
From: Plato (Phaedo [c.382 BCE], 069b) | |
A reaction: Aristotle also says that prudence (phronesis) makes virtue possible. |
370 | Philosophy is a purification of the soul ready for the afterlife [Plato] |
Full Idea: Souls which have purified themselves sufficiently by philosophy will live after death without bodies. | |
From: Plato (Phaedo [c.382 BCE], 114b) | |
A reaction: Purifying it of what? Error, or desire, or narrow-mindedness, or the physical? |
9593 | Progress in philosophy is incremental, not an immature seeking after drama [Williamson] |
Full Idea: The incremental progress which I envisage for philosophy lacks the drama after which some philosophers still hanker, and that hankering is itself a symptom of the intellectual immaturity that helps hold philosophy back. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], Intro) | |
A reaction: This could stand as a motto for the whole current profession of analytical philosophy. It means that if anyone attempts to be dramatic they can make their own way out. They'll find Kripke out there, smoking behind the dustbins. |
350 | In investigation the body leads us astray, but the soul gets a clear view of the facts [Plato] |
Full Idea: When philosophers investigate with the help of the body they are led astray, but through reflection the soul gets a clear view of the facts. | |
From: Plato (Phaedo [c.382 BCE], 065c) |
362 | The greatest misfortune for a person is to develop a dislike for argument [Plato] |
Full Idea: No greater misfortune could happen to anyone than developing a dislike for argument. | |
From: Plato (Phaedo [c.382 BCE], 089d) |
9594 | Correspondence to the facts is a bad account of analytic truth [Williamson] |
Full Idea: Even if talk of truth as correspondence to the facts is metaphorical, it is a bad metaphor for analytic truth in a way that it is not for synthetic truth. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], 3.1) | |
A reaction: A very simple and rather powerful point. Maybe the word 'truth' should be withheld from such cases. You might say that accepted analytic truths are 'conventional'. If that is wrong, then they correspond to natural facts at a high level of abstraction. |
18755 | Validity is explained as truth in all models, because that relies on the logical terms [McGee] |
Full Idea: A model of a language assigns values to non-logical terms. If a sentence is true in every model, its truth doesn't depend on those non-logical terms. Hence the validity of an argument comes from its logical form. Thus models explain logical validity. | |
From: Vann McGee (Logical Consequence [2014], 4) | |
A reaction: [compressed] Thus you get a rigorous account of logical validity by only allowing the rigorous input of model theory. This is the modern strategy of analytic philosophy. But is 'it's red so it's coloured' logically valid? |
18751 | Natural language includes connectives like 'because' which are not truth-functional [McGee] |
Full Idea: Natural language includes connectives that are not truth-functional. In order for 'p because q' to be true, both p and q have to be true, but knowing the simpler sentences are true doesn't determine whether the larger sentence is true. | |
From: Vann McGee (Logical Consequence [2014], 2) |
18761 | Second-order variables need to range over more than collections of first-order objects [McGee] |
Full Idea: To get any advantage from moving to second-order logic, we need to assign to second-order variables a role different from merely ranging over collections made up of things the first-order variables range over. | |
From: Vann McGee (Logical Consequence [2014], 7) | |
A reaction: Thus it is exciting if they range over genuine properties, but not so exciting if you merely characterise those properties as sets of first-order objects. This idea leads into a discussion of plural quantification. |
18753 | An ontologically secure semantics for predicate calculus relies on sets [McGee] |
Full Idea: We can get a less ontologically perilous presentation of the semantics of the predicate calculus by using sets instead of concepts. | |
From: Vann McGee (Logical Consequence [2014], 4) | |
A reaction: The perilous versions rely on Fregean concepts, and notably Russell's 'concept that does not fall under itself'. The sets, of course, have to be ontologically secure, and so will involve the iterative conception, rather than naive set theory. |
18754 | Logically valid sentences are analytic truths which are just true because of their logical words [McGee] |
Full Idea: Logically valid sentences are a species of analytic sentence, being true not just in virtue of the meanings of their words, but true in virtue of the meanings of their logical words. | |
From: Vann McGee (Logical Consequence [2014], 4) | |
A reaction: A helpful link between logical truths and analytic truths, which had not struck me before. |
18757 | Soundness theorems are uninformative, because they rely on soundness in their proofs [McGee] |
Full Idea: Soundness theorems are seldom very informative, since typically we use informally, in proving the theorem, the very same rules whose soundness we are attempting to establish. | |
From: Vann McGee (Logical Consequence [2014], 5) | |
A reaction: [He cites Quine 1935] |
13155 | If you add one to one, which one becomes two, or do they both become two? [Plato] |
Full Idea: I cannot convince myself that when you add one to one either the first or the second one becomes two, or they both become two by the addition of the one to the other, ...or that when you divide one, the cause of becoming two is now the division. | |
From: Plato (Phaedo [c.382 BCE], 097d) | |
A reaction: Lovely questions, all leading to the conclusion that two consists of partaking in duality, to which you can come by several different routes. |
18760 | The culmination of Euclidean geometry was axioms that made all models isomorphic [McGee] |
Full Idea: One of the culminating achievements of Euclidean geometry was categorical axiomatisations, that describe the geometric structure so completely that any two models of the axioms are isomorphic. The axioms are second-order. | |
From: Vann McGee (Logical Consequence [2014], 7) | |
A reaction: [He cites Veblen 1904 and Hilbert 1903] For most mathematicians, categorical axiomatisation is the best you can ever dream of (rather than a single true axiomatisation). |
9601 | The realist/anti-realist debate is notoriously obscure and fruitless [Williamson] |
Full Idea: The debate between realism and anti-realism has become notorious in the rest of philosophy for its obscurity, convolution, and lack of progress. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], After) | |
A reaction: I find this reassuring, because fairly early on I decided that this problem was not of great interest, and quietly tiptoed away. I take the central issue to be whether nature has 'joints', to which the answer appears to be 'yes'. End of story. |
9599 | There cannot be vague objects, so there may be no such thing as a mountain [Williamson] |
Full Idea: It is sometimes argued that if there is such a thing as a mountain it would be a vague object, but it is logically impossible for an object to be vague, so there is no such thing as a mountain. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], 7.2) | |
A reaction: I don't take this to be a daft view. No one is denying the existence of the solid rock that is involved, but allowing such a vague object may be a slippery slope to the acceptance of almost anything as an 'object'. |
21347 | If Simmias is taller than Socrates, that isn't a feature that is just in Simmias [Plato] |
Full Idea: When you say Simmias is taller than Socrates but shorter than Phaedo, so you mean there is in Simmias both tallness and shortness? - I do. ...But surely he is not taller than Socrates because he is Simmias but because of the tallness he happens to have? | |
From: Plato (Phaedo [c.382 BCE], 102b-c) | |
A reaction: He adds that both people must be cited. This appears to be what we now call a rejection relative height as an 'internal' relation, which is it would presumably be if it was a feature of one or of both men. |
360 | We must have a prior knowledge of equality, if we see 'equal' things and realise they fall short of it [Plato] |
Full Idea: We must have some previous knowledge of equality, before the time when we saw equal things, but realised that they fell short of it. | |
From: Plato (Phaedo [c.382 BCE], 075a) |
1 | There is only one source for all beauty [Plato] |
Full Idea: If anything is beautiful other than beauty itself, it is beautiful for no other reason but because it participates in that beautiful. | |
From: Plato (Phaedo [c.382 BCE], 100c) | |
A reaction: The Greek word will be 'kalon' (beautiful, fine, noble). Like Aristotle, I find it baffling that such diversity could have a single source. Beautiful things have diverse aims. |
368 | Other things are named after the Forms because they participate in them [Plato] |
Full Idea: The reason why other things are called after the forms is that they participate in the forms. | |
From: Plato (Phaedo [c.382 BCE], 102a) |
9602 | Common sense and classical logic are often simultaneously abandoned in debates on vagueness [Williamson] |
Full Idea: The constraints of common sense and classical logic are often simultaneously abandoned in debates on vagueness. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], After) | |
A reaction: Wiliamson has described himself (in my hearing) as a 'rottweiller realist', but presumably the problem of vagueness interests a lot of people precisely because it pushes us away from common sense and classical logic. |
16516 | The ship which Theseus took to Crete is now sent to Delos crowned with flowers [Plato] |
Full Idea: The day before the trial the prow of the ship that the Athenians send to Delos had been crowned with garlands. - Which ship is that? - It is the ship in which, the Athenians say, Theseus once sailed to Crete, taking the victims. | |
From: Plato (Phaedo [c.382 BCE], 058a) | |
A reaction: Not philosophical, but this is the Ship of Theseus whose subsequent identity, Plutarch tells us, became a matter of dispute. |
9598 | Modal thinking isn't a special intuition; it is part of ordinary counterfactual thinking [Williamson] |
Full Idea: The epistemology of metaphysical modality requires no dedicated faculty of intuition. It is simply a special case of the epistemology of counterfactual thinking, a kind of thinking tightly integrated with our thinking about the spatio-temporal world. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], 5.6) | |
A reaction: This seems to me to be spot-on, though it puts the focus increasingly on the faculty of imagination, as arguably an even more extraordinary feature of brains than the much-vaunted normal consciousness. |
16536 | Williamson can't base metaphysical necessity on the psychology of causal counterfactuals [Lowe on Williamson] |
Full Idea: The psychological mechanism that Williamson proposes as the supposedly reliable source of our knowledge of necessities only seems applicable to counterfactuals that are distinctively causal, not metaphysical, in character. | |
From: comment on Timothy Williamson (The Philosophy of Philosophy [2007]) by E.J. Lowe - What is the Source of Knowledge of Modal Truths? 5 | |
A reaction: My rough impression of Williamson's account is that it is correct but unilluminating. We have to assess necessities by counterfactual thinking, because nothing else is available (apart from evaluating the coherence of the findings). |
9596 | We scorn imagination as a test of possibility, forgetting its role in counterfactuals [Williamson] |
Full Idea: The epistemology of modality often focuses on (and pours scorn on) imagination or conceivability as a test of possibility, while ignoring the role of the imagination in the assessment of mundane counterfactuals. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], 5.4) | |
A reaction: Good point. I've been guilty of this easy scorn myself. Williamson gives our modal capacities an evolutionary context. What is needed is well-informed imagination, rather than wild fantasy. |
9597 | There are 'armchair' truths which are not a priori, because experience was involved [Williamson] |
Full Idea: There is extensive 'armchair knowledge' in which experience plays no strictly evidential role, but it may not fit the stereotype of the a priori, because the contribution of experience was more than enabling, such as armchair truths about our environment. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], 5.5) | |
A reaction: Once this point is conceded we have no idea where to draw the line. Does 'if it is red it can't be green' derive from experience? I think it might. |
359 | If we feel the inadequacy of a resemblance, we must recollect the original [Plato] |
Full Idea: If someone sees a resemblance, but feels that it falls far short of the original, they must therefore have a recollection of the original. | |
From: Plato (Phaedo [c.382 BCE], 074e) |
357 | People are obviously recollecting when they react to a geometrical diagram [Plato] |
Full Idea: The way in which people react to a geometrical diagram or anything like that is unmistakable proof of the theory of recollection. | |
From: Plato (Phaedo [c.382 BCE], 073a) |
9343 | To achieve pure knowledge, we must get rid of the body and contemplate things with the soul [Plato] |
Full Idea: We are convinced that if we are ever to have pure knowledge of anything, we must get rid of the body and contemplate things by themselves with the soul by itself. | |
From: Plato (Phaedo [c.382 BCE], 066c) | |
A reaction: This seems to be the original ideal which motivates the devotion to a priori knowledge - that it will lead to a 'pure' knowledge, which in Plato's case will be eternal and necessary knowledge, like taking lessons from the gods. Wrong. |
9592 | Intuition is neither powerful nor vacuous, but reveals linguistic or conceptual competence [Williamson] |
Full Idea: Crude rationalists postulate a special knowledge-generating faculty of rational intuition. Crude empiricists regard intuition as an obscurantist term of folk psychology. Linguistic/conceptual philosophy says it reveals linguistic or conceptual competence. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], Intro) | |
A reaction: Kripke seems to think that it is the basis of logical competence. I would use it as a blank term for any insight in which we have considerable confidence, and yet are unable to articulate its basis; roughly, for rational thought that evades logic. |
20181 | When analytic philosophers run out of arguments, they present intuitions as their evidence [Williamson] |
Full Idea: 'Intuition' plays a major role in contemporary analytic philosophy's self-understanding. ...When contemporary analytic philosophers run out of arguments, they appeal to intuitions. ...Thus intuitions are presented as our evidence in philosophy. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], p.214-5), quoted by Herman Cappelen - Philosophy without Intuitions 01.1 | |
A reaction: Williamson says we must investigate this 'scandal', but Cappelen's book says analytic philosophy does not rely on intuition. |
15859 | To investigate the causes of things, study what is best for them [Plato] |
Full Idea: If one wished to know the cause of each thing, why it comes to be or perishes or exists, one had to find what was the best way for it to be, or to be acted upon, or to act. Then it befitted a man to investigate only ...what is best. | |
From: Plato (Phaedo [c.382 BCE], 097d) | |
A reaction: A reversal of the modern idea of 'best explanation'. Socrates is citing Anaxagoras's proposal to understand things by interpreting the workings of a supreme Mind. It is the religious version of best explanation. |
13154 | Do we think and experience with blood, air or fire, or could it be our brain? [Plato] |
Full Idea: Is it with the blood that we think, or with the air or the fire that is in us? Or is it none of these, but the brain that supplies our senses of hearing and sight and smell. | |
From: Plato (Phaedo [c.382 BCE], 097a) | |
A reaction: In retrospect it seems surprising that such clever people hadn't worked this one out, given the evidence of anatomy, in animals and people, and given brain injuries. By the time of Galen they appear to have got the answer. |
364 | One soul can't be more or less of a soul than another [Plato] |
Full Idea: Is one soul, even minutely, more or less of a soul than another? Not in the least. | |
From: Plato (Phaedo [c.382 BCE], 093b) | |
A reaction: This idea is attractive because unconsciousness and death seem to be abrupt procedures, and so appear to be all-or-nothing, but I would personally view extreme Alzheimer's as an erasing of the soul, though a minimum level of it seems all-or-nothing. |
9595 | You might know that the word 'gob' meant 'mouth', but not be competent to use it [Williamson] |
Full Idea: Someone who acquires the word 'gob' just by being reliably told that it is synonymous with 'mouth' knows what 'gob' means without being fully competent to use it. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], 4.7) | |
A reaction: Not exactly an argument against meaning-as-use, but a very nice cautionary example to show that 'knowing the meaning' of a word may be a rather limited, and dangerous, achievement. |
18762 | A maxim claims that if we are allowed to assert a sentence, that means it must be true [McGee] |
Full Idea: If our linguistic conventions entitle us to assert a sentence, they thereby make it true, because of the maxim that 'truth is the norm of assertion'. | |
From: Vann McGee (Logical Consequence [2014], 8) | |
A reaction: You could only really deny that maxim if you had no belief at all in truth, but then you can assert anything you like (with full entitlement). Maybe you can assert anything you like as long as it doesn't upset anyone? Etc. |
361 | It is a mistake to think that the most violent pleasure or pain is therefore the truest reality [Plato] |
Full Idea: When anyone's soul feels a keen pleasure or pain it cannot help supposing that whatever causes the most violent emotion is the plainest and truest reality - which it is not. | |
From: Plato (Phaedo [c.382 BCE], 084c) | |
A reaction: Do people think that? Most people distinguish subjective from objective. Wounded soldiers are also aware of victory or defeat. |
351 | War aims at the acquisition of wealth, because we are enslaved to the body [Plato] |
Full Idea: All wars are undertaken for the acquisition of wealth, and we want this because of the body, to which we are slave. | |
From: Plato (Phaedo [c.382 BCE], 066c) |
9600 | If languages are intertranslatable, and cognition is innate, then cultures are all similar [Williamson] |
Full Idea: Given empirical evidence for the approximate intertranslatability of all human languages, and a universal innate basis of human cognition, we may wonder how 'other' any human culture really is. | |
From: Timothy Williamson (The Philosophy of Philosophy [2007], 8.1) | |
A reaction: This seems to be a fairly accurate account of the situation. In recent centuries people seem to have been over-impressed by superficial differences in cultural behaviour, but we increasingly see the underlying identity. |
13156 | Fancy being unable to distinguish a cause from its necessary background conditions! [Plato] |
Full Idea: Fancy being unable to distinguish between the cause of a thing, and the condition without which it could not be a cause. | |
From: Plato (Phaedo [c.382 BCE], 099c) | |
A reaction: Not as simple as he thinks. It seems fairly easy to construct a case where the immediately impacting event remains constant, and the background condition is changed. Even worse when negligence is held to be the cause. |
369 | If the Earth is spherical and in the centre, it is kept in place by universal symmetry, not by force [Plato] |
Full Idea: If the earth is spherical and in the middle of the heavens, it needs neither air nor force to keep it from falling. The uniformity of heaven and equilibrium of earth are sufficient support. | |
From: Plato (Phaedo [c.382 BCE], 108e) |
363 | Whether the soul pre-exists our body depends on whether it contains the ultimate standard of reality [Plato] |
Full Idea: The theory that our soul exists even before it enters the body surely stands or falls with the soul's possession of the ultimate standard of reality. | |
From: Plato (Phaedo [c.382 BCE], 092d) |