40 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.374 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.374 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.374 BCE], 065c) |
| 24226 | The soul on its own enters a pure, unchanging and eternal realm, and experiences wisdom [Plato] |
| Full Idea: When the soul investigates by itself it passes into the realm of the pure, ever existing, immortal and unchanging, …and its experience is then what is called wisdom | |
| From: Plato (Phaedo [c.374 BCE], 79d) | |
| A reaction: Plato is probably the main source of something we can call 'pure' reason. It is a bit surprising that it took 2,000 years before someone thought to attempt a critique of it. |
| 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.374 BCE], 089d) |
| 18915 | If facts are the truthmakers, they are not in the world [Engelbretsen] |
| Full Idea: If there are such things as truthmakers (facts), they are not to be found in the world. As Strawson would say to Austin: there is the cat, there is the mat, but where in the world is the fact that the cat is on the mat? | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 4) | |
| A reaction: He cites Strawson, Quine and Davidson for this point. |
| 18919 | There are no 'falsifying' facts, only an absence of truthmakers [Engelbretsen] |
| Full Idea: A false proposition is not made false by anything like a 'falsifying' fact. A false proposition simply fails to be made true by any fact. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 4) | |
| A reaction: Sounds good. In truthmaker theory, one truth-value (T) is 'made', but the other one is not, so there is no symmetry between the two. Better to talk of T and not-T? See ideas on Excluded Middle. |
| 18913 | Traditional term logic struggled to express relations [Engelbretsen] |
| Full Idea: The greatest challenge for traditional term logicians was the proper formulation and treatment of relational expressions. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005]) | |
| A reaction: The modern term logic of Fred Sommers claims to have solved this problem. |
| 18907 | Term logic rests on negated terms or denial, and that propositions are tied pairs [Engelbretsen] |
| Full Idea: That terms can be negated, that such negation is distinguishable from denial, and that propositions can be construed syntactically as predicationally tied pairs of terms, are important for the tree theory of predication, and for term logic. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 2) |
| 18912 | Was logic a branch of mathematics, or mathematics a branch of logic? [Engelbretsen] |
| Full Idea: Nineteenth century logicians debated whether logic should be treated simply as a branch of mathematics, and mathematics could be applied to it, or whether mathematics is a branch of logic, with no mathematics used in formulating logic. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 3) | |
| A reaction: He cites Boole, De Morgan and Peirce for the first view, and Frege and Russell (and their 'logicism') for the second. The logic for mathematics slowly emerged from doing it, long before it was formalised. Mathematics is the boss? |
| 18922 | Logical syntax is actually close to surface linguistic form [Engelbretsen] |
| Full Idea: The underlying logical syntax of language is close to the surface syntax of ordinary language. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 5) | |
| A reaction: This is the boast of the Term logicians, in opposition to the strained and unnatural logical forms of predicate logic, which therefore don't give a good account of the way ordinary speakers reason. An attractive programme. 'Terms' are the key. |
| 18905 | Propositions can be analysed as pairs of terms glued together by predication [Engelbretsen] |
| Full Idea: Sommers's 'tree theory' of predication assumes that propositions can be analysed as pairs of terms joined by some kind of predicational glue. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 2) | |
| A reaction: This is the basis of Sommers's upgraded Aristotelian logic, known as Term Logic. The idea of reasoning with 'terms', rather than with objects, predicates and quantifiers, seems to me very appealing. I think I reason more about facts than about objects. |
| 18908 | Standard logic only negates sentences, even via negated general terms or predicates [Engelbretsen] |
| Full Idea: Standard logic recognises only one kind of negation: sentential negation. Consequently, negation of a general term/predicate always amounts to negation of the entire sentence. | |
| From: George Engelbretsen (Trees, Terms and Truth [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.374 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. |
| 18917 | Existence and nonexistence are characteristics of the world, not of objects [Engelbretsen] |
| Full Idea: Existence and nonexistence are not primarily properties of individual objects (dogs, unicorns), but of totalities. To say that some object exists is just to say that it is a constituent of the world, which is a characteristic of the world, not the object. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 4) | |
| A reaction: This has important implications for the problem of truthmakers for negative existential statements (like 'there are no unicorns'). It is obviously a relative of Armstrong's totality facts that do the job. Not sure about 'a characteristic of'. |
| 18916 | Facts are not in the world - they are properties of the world [Engelbretsen] |
| Full Idea: Facts must be viewed as properties of the world - not as things in the world. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 4) | |
| A reaction: Not sure I'm happy with either of these. Do animals grasp facts? If not, are they (as Strawson said) just the truths expressed by true sentences? That is not a clear idea either, given that facts are not the sentences themselves. Facts overlap. |
| 18921 | Individuals are arranged in inclusion categories that match our semantics [Engelbretsen] |
| Full Idea: The natural categories of individuals are arranged in a hierarchy of inclusion relations that is isomorphic with the linguistic semantic structure. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 5) | |
| A reaction: This is the conclusion of a summary of modern Term Logic. The claim is that Sommers discerned this structure in our semantics (via the study of 'terms'), and was pleasantly surprised to find that it matched a plausible structure of natural categories. |
| 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.374 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.374 BCE], 075a) |
| 24230 | The Forms arise whenever we talk of something 'in itself'. [Plato] |
| Full Idea: Our present argument is about …the Equal, the Beautiful itself, the Good itself, the Just, the Pious, and about all those things to which we can attach the word 'itself', both when we are putting questions and when we are answering them. | |
| From: Plato (Phaedo [c.374 BCE], 75d) | |
| A reaction: This identifies the Forms with ideas which emerge during philosophical conversation (either the 'elenchus' interrogation or the 'dialectic' discussion). So they arise from using language. The 'itself' test works quite well in English. Cf essentialism. |
| 24225 | Things like the Equal and the Beautiful, which are real, must be unchanging [Plato] |
| Full Idea: Are these things ever the same …or do they vary from one time to another; can the Equal itself, the Beautiful itself, …the real, ever be affected by any change? - It must remain the same. …They can only be grasped by the reasoning part of the mind. | |
| From: Plato (Phaedo [c.374 BCE], 78d) | |
| A reaction: Note the assertion that they are 'real', as well as unchanging. It is hard to make sense of 'the Equal' as a Form. We can more easily see what is in common among beautiful things. The number three is equal and unequal. But see 74d. |
| 24227 | One and one can only become two by sharing in Twoness [Plato] |
| Full Idea: You do not know how else [when one is added to one it becomes two] except by sharing in a particular reality, which does not have any other cause of becoming two except by sharing in Twoness, …as that which is one must share in Oneness. | |
| From: Plato (Phaedo [c.374 BCE], 101c) | |
| A reaction: Close readers of such passages have always been baffled by what sharing [partaking, metechein] could actually mean. How can two apples 'share' a pure eternal idea? The best approach is, I'm afraid, mental files. |
| 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.374 BCE], 102a) |
| 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.374 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. |
| 6019 | If someone squashed a horse to make a dog, something new would now exist [Mnesarchus] |
| Full Idea: If, for the sake of argument, someone were to mould a horse, squash it, then make a dog, it would be reasonable for us on seeing this to say that this previously did not exist but now does exist. | |
| From: Mnesarchus (fragments/reports [c.120 BCE]), quoted by John Stobaeus - Anthology 179.11 | |
| A reaction: Locke would say it is new, because the substance is the same, but a new life now exists. A sword could cease to exist and become a new ploughshare, I would think. Apply this to the Ship of Theseus. Is form more important than substance? |
| 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.374 BCE], 058a) | |
| A reaction: Not philosophical, but this is the Ship of Theseus whose subsequent identity, Plutarch tells us, became a matter of dispute. |
| 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.374 BCE], 073a) |
| 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.374 BCE], 074e) |
| 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.374 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.374 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.374 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.374 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. |
| 18918 | Terms denote objects with properties, and statements denote the world with that property [Engelbretsen] |
| Full Idea: In term logic, what a term denotes are the objects having the property it signifies. What a statement denotes is the world, that which has the constitutive property it signifies. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 4) |
| 18920 | 'Socrates is wise' denotes a sentence; 'that Socrates is wise' denotes a proposition [Engelbretsen] |
| Full Idea: Whereas 'Socrates is wise' denotes a sentence, 'that Socrates is wise' denotes a proposition. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 4) | |
| A reaction: In traditional parlance, 'reported speech' refers to the underlying proposition, because it does not commit to the actual words being used. As a lover of propositions (as mental events, not mysterious abstract objects), I like this. |
| 18906 | Negating a predicate term and denying its unnegated version are quite different [Engelbretsen] |
| Full Idea: There is a crucial distinction in term logic between affirming a negated predicate term of some subject and denying the unnegated version of that term of that same subject. We must distinguish 'X is non-P' from 'X is not P'. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 2) | |
| A reaction: The first one affirms something about X, but the second one just blocks off a possible description of X. 'X is non-harmful' and 'X is not harmful' - if X had ceased to exist, the second would be appropriate and the first wouldn't? I'm guessing. |
| 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.374 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.374 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.374 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.374 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.374 BCE], 092d) |