32 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? |
| 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) |
| 10688 | 'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall] |
| Full Idea: 'Equivocation' is when the terms do not mean the same thing in the premises and in the conclusion. | |
| From: JC Beall / G Restall (Logical Consequence [2005], Intro) |
| 10690 | Formal logic is invariant under permutations, or devoid of content, or gives the norms for thought [Beall/Restall] |
| Full Idea: Logic is purely formal either when it is invariant under permutation of object (Tarski), or when it has totally abstracted away from all contents, or it is the constitutive norms for thought. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) | |
| A reaction: [compressed] The third account sounds rather woolly, and the second one sounds like a tricky operation, but the first one sounds clear and decisive, so I vote for Tarski. |
| 10691 | Logical consequence needs either proofs, or absence of counterexamples [Beall/Restall] |
| Full Idea: Technical work on logical consequence has either focused on proofs, where validity is the existence of a proof of the conclusions from the premises, or on models, which focus on the absence of counterexamples. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 10695 | Logical consequence is either necessary truth preservation, or preservation based on interpretation [Beall/Restall] |
| Full Idea: Two different views of logical consequence are necessary truth-preservation (based on modelling possible worlds; favoured by Realists), or truth-preservation based on the meanings of the logical vocabulary (differing in various models; for Anti-Realists). | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) | |
| A reaction: Thus Dummett prefers the second view, because the law of excluded middle is optional. My instincts are with the first one. |
| 10689 | A step is a 'material consequence' if we need contents as well as form [Beall/Restall] |
| Full Idea: A logical step is a 'material consequence' and not a formal one, if we need the contents as well as the structure or form. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) |
| 10696 | A 'logical truth' (or 'tautology', or 'theorem') follows from empty premises [Beall/Restall] |
| Full Idea: If a conclusion follows from an empty collection of premises, it is true by logic alone, and is a 'logical truth' (sometimes a 'tautology'), or, in the proof-centred approach, 'theorems'. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 4) | |
| A reaction: These truths are written as following from the empty set Φ. They are just implications derived from the axioms and the rules. |
| 10693 | Models are mathematical structures which interpret the non-logical primitives [Beall/Restall] |
| Full Idea: Models are abstract mathematical structures that provide possible interpretations for each of the non-logical primitives in a formal language. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 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. |
| 10692 | Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall] |
| Full Idea: There are many proof-systems, the main being Hilbert proofs (with simple rules and complex axioms), or natural deduction systems (with few axioms and many rules, and the rules constitute the meaning of the connectives). | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 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) |
| 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. |
| 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. |
| 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. |
| 2427 | Maybe understanding doesn't need consciousness, despite what Searle seems to think [Searle, by Chalmers] |
| Full Idea: Searle originally directed the Chinese Room against machine intentionality rather than consciousness, arguing that it is "understanding" that the room lacks,….but on Searle's view intentionality requires consciousness. | |
| From: report of John Searle (Minds, Brains and Science [1984]) by David J.Chalmers - The Conscious Mind 4.9.4 | |
| A reaction: I doubt whether 'understanding' is a sufficiently clear and distinct concept to support Searle's claim. Understanding comes in degrees, and we often think and act with minimal understanding. |
| 7389 | A program won't contain understanding if it is small enough to imagine [Dennett on Searle] |
| Full Idea: There is nothing remotely like genuine understanding in any hunk of programming small enough to imagine readily. | |
| From: comment on John Searle (Minds, Brains and Science [1984]) by Daniel C. Dennett - Consciousness Explained 14.1 | |
| A reaction: We mustn't hide behind 'complexity', but I think Dennett is right. It is important to think of speed as well as complexity. Searle gives the impression that he knows exactly what 'understanding' is, but I doubt if anyone else does. |
| 7390 | If bigger and bigger brain parts can't understand, how can a whole brain? [Dennett on Searle] |
| Full Idea: The argument that begins "this little bit of brain activity doesn't understand Chinese, and neither does this bigger bit..." is headed for the unwanted conclusion that even the activity of the whole brain won't account for understanding Chinese. | |
| From: comment on John Searle (Minds, Brains and Science [1984]) by Daniel C. Dennett - Consciousness Explained 14.1 | |
| A reaction: In other words, Searle is guilty of a fallacy of composition (in negative form - parts don't have it, so whole can't have it). Dennett is right. The whole shebang of the full brain will obviously do wonderful (and commonplace) things brain bits can't. |
| 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) |
| 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) |