57 ideas
| 224 | When questions are doubtful we should concentrate not on objects but on ideas of the intellect [Plato] |
| Full Idea: Doubtful questions should not be discussed in terms of visible objects or in relation to them, but only with reference to ideas conceived by the intellect. | |
| From: Plato (Parmenides [c.364 BCE], 135e) |
| 232 | Opposites are as unlike as possible [Plato] |
| Full Idea: Opposites are as unlike as possible. | |
| From: Plato (Parmenides [c.364 BCE], 159a) |
| 8937 | Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic [Hegel on Plato] |
| Full Idea: Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic. | |
| From: comment on Plato (Parmenides [c.364 BCE]) by Georg W.F.Hegel - Phenomenology of Spirit Pref 71 | |
| A reaction: It is a long way from the analytic tradition of philosophy to be singling out a classic text for its 'artistic' achievement. Eventually we may even look back on, say, Kripke's 'Naming and Necessity' and see it in that light. |
| 15375 | If terms change their designations in different states, they are functions from states to objects [Fitting] |
| Full Idea: The common feature of every designating term is that designation may change from state to state - thus it can be formalized by a function from states to objects. | |
| From: Melvin Fitting (Intensional Logic [2007], 3) | |
| A reaction: Specifying the objects sounds OK, but specifying states sounds rather tough. |
| 15376 | Intensional logic adds a second type of quantification, over intensional objects, or individual concepts [Fitting] |
| Full Idea: To first order modal logic (with quantification over objects) we can add a second kind of quantification, over intensions. An intensional object, or individual concept, will be modelled by a function from states to objects. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.3) |
| 15378 | Awareness logic adds the restriction of an awareness function to epistemic logic [Fitting] |
| Full Idea: Awareness logic enriched Hintikka's epistemic models with an awareness function, mapping each state to the set of formulas we are aware of at that state. This reflects some bound on the resources we can bring to bear. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.6.1) | |
| A reaction: [He cites Fagin and Halpern 1988 for this] |
| 15379 | Justication logics make explicit the reasons for mathematical truth in proofs [Fitting] |
| Full Idea: In justification logics, the logics of knowledge are extended by making reasons explicit. A logic of proof terms was created, with a semantics. In this, mathematical truths are known for explicit reasons, and these provide a measure of complexity. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.6.1) |
| 11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
| Full Idea: Mathematics is typically extensional throughout (we write 3+2=2+3 despite the two terms having different meanings). ..Classical first-order logic is extensional by design since it primarily evolved to model the reasoning of mathematics. | |
| From: Melvin Fitting (Intensional Logic [2007], §1) |
| 11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
| Full Idea: λ-abstraction can be used to abstract and disambiguate a predicate. De re is [λx◊P(x)](f) - f has the possible-P property - and de dicto is ◊[λxP(x)](f) - possibly f has the P-property. Also applies to □. | |
| From: Melvin Fitting (Intensional Logic [2007], §3.3) | |
| A reaction: Compare the Barcan formula. Originated with Church in the 1930s, and Carnap 1947, but revived by Stalnaker and Thomason 1968. Because it refers to the predicate, it has a role in intensional versions of logic, especially modal logic. |
| 13986 | Plato found antinomies in ideas, Kant in space and time, and Bradley in relations [Plato, by Ryle] |
| Full Idea: Plato (in 'Parmenides') shows that the theory that 'Eide' are substances, and Kant that space and time are substances, and Bradley that relations are substances, all lead to aninomies. | |
| From: report of Plato (Parmenides [c.364 BCE]) by Gilbert Ryle - Are there propositions? 'Objections' |
| 14150 | Plato's 'Parmenides' is perhaps the best collection of antinomies ever made [Russell on Plato] |
| Full Idea: Plato's 'Parmenides' is perhaps the best collection of antinomies ever made. | |
| From: comment on Plato (Parmenides [c.364 BCE]) by Bertrand Russell - The Principles of Mathematics §337 |
| 16150 | One is, so numbers exist, so endless numbers exist, and each one must partake of being [Plato] |
| Full Idea: If one is, there must also necessarily be number - Necessarily - But if there is number, there would be many, and an unlimited multitude of beings. ..So if all partakes of being, each part of number would also partake of it. | |
| From: Plato (Parmenides [c.364 BCE], 144a) | |
| A reaction: This seems to commit to numbers having being, then to too many numbers, and hence to too much being - but without backing down and wondering whether numbers had being after all. Aristotle disagreed. |
| 229 | The one was and is and will be and was becoming and is becoming and will become [Plato] |
| Full Idea: The one was and is and will be and was becoming and is becoming and will become. | |
| From: Plato (Parmenides [c.364 BCE], 155d) |
| 21821 | Plato's Parmenides has a three-part theory, of Primal One, a One-Many, and a One-and-Many [Plato, by Plotinus] |
| Full Idea: The Platonic Parmenides is more exact [than Parmenides himself]; the distinction is made between the Primal One, a strictly pure Unity, and a secondary One which is a One-Many, and a third which is a One-and-Many. | |
| From: report of Plato (Parmenides [c.364 BCE]) by Plotinus - The Enneads 5.1.08 | |
| A reaction: Plotinus approves of this three-part theory. Parmenides has the problem that the highest Being contains no movement. By placing the One outside Being you can give it powers which an existent thing cannot have. Cf the concept of God. |
| 221 | Absolute ideas, such as the Good and the Beautiful, cannot be known by us [Plato] |
| Full Idea: The absolute good and the beautiful and all which we conceive to be absolute ideas are unknown to us. | |
| From: Plato (Parmenides [c.364 BCE], 134c) |
| 227 | You must always mean the same thing when you utter the same name [Plato] |
| Full Idea: You must always mean the same thing when you utter the same name. | |
| From: Plato (Parmenides [c.364 BCE], 147d) |
| 223 | If you deny that each thing always stays the same, you destroy the possibility of discussion [Plato] |
| Full Idea: If a person denies that the idea of each thing is always the same, he will utterly destroy the power of carrying on discussion. | |
| From: Plato (Parmenides [c.364 BCE], 135c) |
| 210 | It would be absurd to think there were abstract Forms for vile things like hair, mud and dirt [Plato] |
| Full Idea: Are there abstract ideas for such things as hair, mud and dirt, which are particularly vile and worthless? That would be quite absurd. | |
| From: Plato (Parmenides [c.364 BCE], 130d) |
| 220 | The concept of a master includes the concept of a slave [Plato] |
| Full Idea: Mastership in the abstract is mastership of slavery in the abstract. | |
| From: Plato (Parmenides [c.364 BCE], 133e) |
| 211 | If admirable things have Forms, maybe everything else does as well [Plato] |
| Full Idea: It is troubling that if admirable things have abstract ideas, then perhaps everything else must have ideas as well. | |
| From: Plato (Parmenides [c.364 BCE], 130d) |
| 219 | If absolute ideas existed in us, they would cease to be absolute [Plato] |
| Full Idea: None of the absolute ideas exists in us, because then it would no longer be absolute. | |
| From: Plato (Parmenides [c.364 BCE], 133c) |
| 228 | Greatness and smallness must exist, to be opposed to one another, and come into being in things [Plato] |
| Full Idea: These two ideas, greatness and smallness, exist, do they not? For if they did not exist, they could not be opposites of one another, and could not come into being in things. | |
| From: Plato (Parmenides [c.364 BCE], 149e) |
| 16151 | Plato moves from Forms to a theory of genera and principles in his later work [Plato, by Frede,M] |
| Full Idea: It seems to me that Plato in the later dialogues, beginning with the second half of 'Parmenides', wants to substitute a theory of genera and theory of principles that constitute these genera for the earlier theory of forms. | |
| From: report of Plato (Parmenides [c.364 BCE]) by Michael Frede - Title, Unity, Authenticity of the 'Categories' V | |
| A reaction: My theory is that the later Plato came under the influence of the brilliant young Aristotle, and this idea is a symptom of it. The theory of 'principles' sounds like hylomorphism to me. |
| 218 | Participation is not by means of similarity, so we are looking for some other method of participation [Plato] |
| Full Idea: Participation is not by means of likeness, so we must seek some other method of participation. | |
| From: Plato (Parmenides [c.364 BCE], 133a) |
| 212 | The whole idea of each Form must be found in each thing which participates in it [Plato] |
| Full Idea: The whole idea of each form (of beauty, justice etc) must be found in each thing which participates in it. | |
| From: Plato (Parmenides [c.364 BCE], 131a) |
| 213 | Each idea is in all its participants at once, just as daytime is a unity but in many separate places at once [Plato] |
| Full Idea: Just as day is in many places at once, but not separated from itself, so each idea might be in all its participants at once. | |
| From: Plato (Parmenides [c.364 BCE], 131b) |
| 216 | If things are made alike by participating in something, that thing will be the absolute idea [Plato] |
| Full Idea: That by participation in which like things are made like, will be the absolute idea, will it not? | |
| From: Plato (Parmenides [c.364 BCE], 132e) |
| 215 | If things partake of ideas, this implies either that everything thinks, or that everything actually is thought [Plato] |
| Full Idea: If all things partake of ideas, must either everything be made of thoughts and everything thinks, or everything is thought, and so can't think? | |
| From: Plato (Parmenides [c.364 BCE], 132c) |
| 217 | Nothing can be like an absolute idea, because a third idea intervenes to make them alike (leading to a regress) [Plato] |
| Full Idea: It is impossible for anything to be like an absolute idea, because a third idea will appear to make them alike, and if that is like anything, it will lead to another idea, and so on. | |
| From: Plato (Parmenides [c.364 BCE], 133a) |
| 214 | If absolute greatness and great things are seen as the same, another thing appears which makes them seem great [Plato] |
| Full Idea: If you regard the absolute great and the many great things in the same way, will not another appear beyond, by which all these must appear to be great? | |
| From: Plato (Parmenides [c.364 BCE], 132a) |
| 15851 | Parts must belong to a created thing with a distinct form [Plato] |
| Full Idea: The part would not be the part of many things or all, but of some one character ['ideas'] and of some one thing, which we call a 'whole', since it has come to be one complete [perfected] thing composed [created] of all. | |
| From: Plato (Parmenides [c.364 BCE], 157d) | |
| A reaction: A serious shot by Plato at what identity is. Harte quotes it (125) and shows that 'character' is Gk 'idea', and 'composed' will translate as 'created'. 'Form' links this Platonic passage to Aristotle's hylomorphism. |
| 15846 | In Parmenides, if composition is identity, a whole is nothing more than its parts [Plato, by Harte,V] |
| Full Idea: At the heart of the 'Parmenides' puzzles about composition is the thesis that composition is identity. Considered thus, a whole adds nothing to an ontology that already includes its parts | |
| From: report of Plato (Parmenides [c.364 BCE]) by Verity Harte - Plato on Parts and Wholes 2.5 | |
| A reaction: There has to be more to a unified identity that mere proximity of the parts. When do parts come together, and when do they actually 'compose' something? |
| 15849 | Plato says only a one has parts, and a many does not [Plato, by Harte,V] |
| Full Idea: In 'Parmenides' it is argued that a part cannot be part of a many, but must be part of something one. | |
| From: report of Plato (Parmenides [c.364 BCE], 157c) by Verity Harte - Plato on Parts and Wholes 3.2 | |
| A reaction: This looks like the right way to go with the term 'part'. We presuppose a unity before we even talk of its parts, so we can't get into contradictions and paradoxes about their relationships. |
| 15850 | Anything which has parts must be one thing, and parts are of a one, not of a many [Plato] |
| Full Idea: The whole of which the parts are parts must be one thing composed of many; for each of the parts must be part, not of a many, but of a whole. | |
| From: Plato (Parmenides [c.364 BCE], 157c) | |
| A reaction: This is a key move of metaphysics, and we should hang on to it. The other way madness lies. |
| 13259 | It seems that the One must be composed of parts, which contradicts its being one [Plato] |
| Full Idea: The One must be composed of parts, both being a whole and having parts. So on both grounds the One would thus be many and not one. But it must be not many, but one. So if the One will be one, it will neither be a whole, nor have parts. | |
| From: Plato (Parmenides [c.364 BCE], 137c09), quoted by Kathrin Koslicki - The Structure of Objects 5.2 | |
| A reaction: This is the starting point for Plato's metaphysical discussion of objects. It seems to begin a line of thought which is completed by Aristotle, surmising that only an essential structure can bestow identity on a bunch of parts. |
| 15847 | Two things relate either as same or different, or part of a whole, or the whole of the part [Plato] |
| Full Idea: Everything is surely related to everything as follows: either it is the same or different; or, if it is not the same or different, it would be related as part to whole or as whole to part. | |
| From: Plato (Parmenides [c.364 BCE], 146b) | |
| A reaction: This strikes me as a really helpful first step in trying to analyse the nature of identity. Two things are either two or (actually) one, or related mereologically. |
| 15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |
| Full Idea: Definite descriptions pick out different objects in different possible worlds quite naturally. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.4) | |
| A reaction: A definite description can pick out the same object in another possible world, or a very similar one, or an object which has almost nothing in common with the others. |
| 21233 | The beautiful is whatever it is intrinsically good to admire [Moore,GE] |
| Full Idea: The beautiful should be defined as that of which the admiring contemplation is good in itself. | |
| From: G.E. Moore (Principia Ethica [1903], p.210), quoted by Graham Farmelo - The Strangest Man | |
| A reaction: To work, this definition must exclude anything else which it is intrinsically good to admire. Good deeds obviously qualify for that, so good deeds must be intrinsically beautiful (which would be agreed by ancient Greeks). We can't ask WHY it is good! |
| 8039 | Moore tries to show that 'good' is indefinable, but doesn't understand what a definition is [MacIntyre on Moore,GE] |
| Full Idea: Moore tries to show that 'good' is indefinable by relying on a bad dictionary definition of 'definition'. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Alasdair MacIntyre - After Virtue: a Study in Moral Theory Ch.2 | |
| A reaction: An interesting remark, with no further explanation offered. If Moore has this problem, then Plato had it too (see Idea 3032). I would have thought that any definition MacIntyre could offer would either be naturalistic, or tautological. |
| 22151 | The Open Question argument leads to anti-realism and the fact-value distinction [Boulter on Moore,GE] |
| Full Idea: Moore's Open Question argument led, however unintentionally, to the rise of anti-realism in meta-ethics (which leads to distinguishing values from facts). | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Stephen Boulter - Why Medieval Philosophy Matters 4 | |
| A reaction: I presume that Moore proves that the Good is not natural, and after that no one knows what it is, so it seems to be arbitrary or non-existent (rather than the platonic fact that Moore had hoped for). I vote for naturalistic ethics. |
| 11056 | The naturalistic fallacy claims that natural qualties can define 'good' [Moore,GE] |
| Full Idea: The naturalistic fallacy ..consists in the contention that good means nothing but some simple or complex notion, that can be defined in terms of natural qualities. | |
| From: G.E. Moore (Principia Ethica [1903], §044) | |
| A reaction: Presumably aimed at those who think morality is pleasure and pain. We could hardly attribute morality to non-human qualities. I connect morality to human deliberative functions. |
| 8033 | Moore cannot show why something being good gives us a reason for action [MacIntyre on Moore,GE] |
| Full Idea: Moore's account leaves it entirely unexplained and inexplicable why something's being good should ever furnish us with a reason for action. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Alasdair MacIntyre - A Short History of Ethics Ch.18 | |
| A reaction: The same objection can be raised to Plato's Form of the Good, but Plato's answer seems to be that the Good is partly a rational entity, and partly that the Good just has a natural magnetism that makes it quasi-religious. |
| 8032 | Can learning to recognise a good friend help us to recognise a good watch? [MacIntyre on Moore,GE] |
| Full Idea: How could having learned to recognize a good friend help us to recognize a good watch? Yet is Moore is right, the same simple property is present in both cases? | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Alasdair MacIntyre - A Short History of Ethics Ch.18 | |
| A reaction: It begins to look as if what they have in common is just that they both make you feel good. However, I like the Aristotelian idea that they both function succesfully, one as a timekeeper, the other as a citizen or companion. |
| 11050 | Moore's combination of antinaturalism with strong supervenience on the natural is incoherent [Hanna on Moore,GE] |
| Full Idea: Moore incoherently combines his antinaturalism with the thesis that intrinsic-value properties are logically strongly supervenient on (or explanatorily reducible to) natural facts. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Robert Hanna - Rationality and Logic Ch.1 | |
| A reaction: I take this to be Moore fighting shy of the strongly Platonist view of values which his arguments all seemed to imply. |
| 23726 | Despite Moore's caution, non-naturalists incline towards intuitionism [Moore,GE, by Smith,M] |
| Full Idea: Although Moore was reluctant to adopt it, the epistemology the non-naturalists tended to favour was intuitionism. | |
| From: report of G.E. Moore (Principia Ethica [1903]) by Michael Smith - The Moral Problem 2.2 | |
| A reaction: Moore was presumably reluctant because intuitionism had been heavily criticised in the past for its inability to settle moral disputes. But if you insist that goodness is outside nature, what other means of knowing it is available? Reason? |
| 18676 | We should ask what we would judge to be good if it existed in absolute isolation [Moore,GE] |
| Full Idea: It is necessary to consider what things are such that, if they existed by themselves, in absolute isolation, we should yet judge their existence to be good. | |
| From: G.E. Moore (Principia Ethica [1903], §112) | |
| A reaction: This is known as the 'isolation test'. The test has an instant appeal, but looks a bit odd after a little thought. The value of most things drains out of them if they are totally isolated. The MS of the Goldberg Variations floating in outer space? |
| 11057 | It is always an open question whether anything that is natural is good [Moore,GE] |
| Full Idea: Good does not, by definition, mean anything that is natural; and it is therefore always an open question whether anything that is natural is good. | |
| From: G.E. Moore (Principia Ethica [1903], §027) | |
| A reaction: This is the best known modern argument for Platonist idealised ethics. But maybe there is no end to questioning anywhere, so each theory invites a further question, and nothing is ever fully explained? Next stop - pragmatism. |
| 5925 | The three main values are good, right and beauty [Moore,GE, by Ross] |
| Full Idea: Moore describes rightness and beauty as the two main value-attributes, apart from goodness. | |
| From: report of G.E. Moore (Principia Ethica [1903]) by W. David Ross - The Right and the Good §IV | |
| A reaction: This was a last-throw of the Platonic ideal, before we plunged into the value-free world of Darwin and the physicists. It is hard to agree with Moore, but also hard to disagree. Why do many people despise or ignore these values? |
| 5902 | For Moore, 'right' is what produces good [Moore,GE, by Ross] |
| Full Idea: Moore claims that 'right' means 'productive of the greatest possible good'. | |
| From: report of G.E. Moore (Principia Ethica [1903]) by W. David Ross - The Right and the Good §I | |
| A reaction: Ross is at pains to keep 'right' and 'good' as quite distinct notions. Some actions are right but very unpleasant, and seem to produce no real good at all. |
| 5903 | 'Right' means 'cause of good result' (hence 'useful'), so the end does justify the means [Moore,GE] |
| Full Idea: 'Right' does and can mean nothing but 'cause of a good result', and is thus identical with 'useful', whence it follows that the end always will justify the means. | |
| From: G.E. Moore (Principia Ethica [1903], §089) | |
| A reaction: Of course, Moore does not identify utility with pleasure, as his notion of what is good concerns fairly Platonic ideals. Would Stalin's murders have been right if Russia were now the happiest nation on Earth? |
| 5907 | Relationships imply duties to people, not merely the obligation to benefit them [Ross on Moore,GE] |
| Full Idea: Moore's 'Ideal Utilitarianism' seems to unduly simplify our relations to our fellows. My neighbours are merely possible beneficiaries by my action. But they also stand to me as promiser, creditor, husband, friend, which entails prima facie duties. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by W. David Ross - The Right and the Good §II | |
| A reaction: Perhaps it is better to say that we have obligations to benefit particular people, because of our obligations, and that we are confined to particular benefits which meet those obligations - not just any old benefit to any old person. |
| 222 | Only a great person can understand the essence of things, and an even greater person can teach it [Plato] |
| Full Idea: Only a man of very great natural gifts will be able to understand that everything has a class and absolute essence, and an even more wonderful man can teach this. | |
| From: Plato (Parmenides [c.364 BCE], 135a) |
| 225 | The unlimited has no shape and is endless [Plato] |
| Full Idea: The unlimited partakes neither of the round nor of the straight, because it has no ends nor edges. | |
| From: Plato (Parmenides [c.364 BCE], 137e) |
| 233 | Some things do not partake of the One [Plato] |
| Full Idea: The others cannot partake of the one in any way; they can neither partake of it nor of the whole. | |
| From: Plato (Parmenides [c.364 BCE], 159d) | |
| A reaction: Compare Idea 231 |
| 2062 | The only movement possible for the One is in space or in alteration [Plato] |
| Full Idea: If the One moves it either moves spatially or it is altered, since these are the only motions. | |
| From: Plato (Parmenides [c.364 BCE], 138b) |
| 231 | Everything partakes of the One in some way [Plato] |
| Full Idea: The others are not altogether deprived of the one, for they partake of it in some way. | |
| From: Plato (Parmenides [c.364 BCE], 157c) | |
| A reaction: Compare Idea 233. |
| 234 | We couldn't discuss the non-existence of the One without knowledge of it [Plato] |
| Full Idea: There must be knowledge of the one, or else not even the meaning of the words 'if the one does not exist' would be known. | |
| From: Plato (Parmenides [c.364 BCE], 160d) |