58 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) |
23250 | Desired responsible actions result either from rational or from irrational desire [Aristotle] |
Full Idea: And of responsible actions, some are done through habit, some through desire, and of these some through rational and some through irrational desire. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1369a01) | |
A reaction: Identified by Michael Frede, to illustrate reason having its own distinctive type of desire ('Boulesis'). I suspect that the rational desires are the morally good desires. |
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. |
5847 | It is the role of dialectic to survey syllogisms [Aristotle] |
Full Idea: It belongs to dialectic to survey equally all kinds of syllogism. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1355a08) | |
A reaction: Since dialectic is central to philosophy, this implies that philosophers ought to be students of logic. This duty seems to me to be taken more seriously in the analytical tradition than in the 'continental' tradition. |
15327 | Kripke's semantic theory has actually inspired promising axiomatic theories [Kripke, by Horsten] |
Full Idea: Kripke has a semantic theory of truth which has inspired promising axiomatic theories of truth. | |
From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Leon Horsten - The Tarskian Turn 01.2 | |
A reaction: Feferman produced an axiomatic version of Kripke's semantic theory. |
15343 | Kripke offers a semantic theory of truth (involving models) [Kripke, by Horsten] |
Full Idea: One of the most popular semantic theories of truth is Kripke's theory. It describes a class of models which themselves involve a truth predicate (unlike Tarski's semantic theory). | |
From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Leon Horsten - The Tarskian Turn 02.3 | |
A reaction: The modern versions explored by Horsten are syntactic versions of this, derived from Feferman's axiomatisation of the Kripke theory. |
14966 | The Tarskian move to a metalanguage may not be essential for truth theories [Kripke, by Gupta] |
Full Idea: Kripke established that, contrary to the prevalent Tarskian dogma, attributions of truth do not always force a move to a metalanguage. | |
From: report of Saul A. Kripke (Outline of a Theory of Truth [1975], 5.1) by Anil Gupta - Truth | |
A reaction: [Gupta also cites Martin and Woodruff 1975] |
14967 | Certain three-valued languages can contain their own truth predicates [Kripke, by Gupta] |
Full Idea: Kripke showed via a fixed-point argument that certain three-valued languages can contain their own truth predicates. | |
From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Anil Gupta - Truth | |
A reaction: [Gupta also cites Martin and Woodruff 1975] It is an odd paradox that truth can only be included if one adds a truth-value of 'neither true nor false'. The proposed three-valued system is 'strong Kleene logic'. |
16328 | Kripke classified fixed points, and illuminated their use for clarifications [Kripke, by Halbach] |
Full Idea: Kripke's main contribution was …his classification of the different consistent fixed points and the discussion of their use for discriminating between ungrounded sentences, paradoxical sentences, and so on. | |
From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Volker Halbach - Axiomatic Theories of Truth 15.1 |
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) |
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. |
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) |
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) |
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) |
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) |
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) |
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) |
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) |
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) |
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) |
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. |
5862 | A single counterexample is enough to prove that a truth is not necessary [Aristotle] |
Full Idea: If we have a single counter-instance, the argument is refuted as not necessary, even if more cases are otherwise or more often otherwise. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1403a07) | |
A reaction: This is Aristotle (pioneering hero) pointing out what we now tend to think of as Karl Popper's falsification, the certain way to demonstrate the falseness of a supposed law of nature, by finding one anomaly from it. |
5854 | Nobody fears a disease which nobody has yet caught [Aristotle] |
Full Idea: Nobody is on his guard against a disease that nobody has yet caught. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1372a27) | |
A reaction: A beautifully simple indication of one problem with induction. In a dangerous situation, you can't wait around for a few experiences in order to learn the regularities and rules. Either you are doomed, or you must explain using related experiences. |
5849 | Rhetoric is a political offshoot of dialectic and ethics [Aristotle] |
Full Idea: Rhetoric is a kind of offshoot of dialectic and of the study of ethics, and is quite properly categorized as political. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1356a25) | |
A reaction: Aristotle gives a higher status to rhetoric than Socrates and Plato did - and rightly, in my view. We have lost sight of it as a vital part of politics, and philosophers must fight for virtue in rhetoric, which requires right reason and fine principles. |
5851 | Pentathletes look the most beautiful, because they combine speed and strength [Aristotle] |
Full Idea: The pentathletes are the most beautiful, being at the same time naturally suited to both speed and force. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1361b09) | |
A reaction: This is still true. Watch the Olympics. The bodies we envy most belong to those who do a variety of disciplines. The most beautiful music fulfils a variety of functions (structure, as well as melody, drama, rhythm, harmony, novelty). |
5858 | Men are physically prime at thirty-five, and mentally prime at forty-nine [Aristotle] |
Full Idea: The body is in its prime from the ages of thirty to thirty-five, and the soul around the age of forty-nine. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1390b09) | |
A reaction: Wonderfully specific! It is important that Aristotle is interested in these questions. The good for man follows the path laid out by nature, in which a man rises to his highest good in maturity, and then declines from it into old age. |
5855 | We all feel universal right and wrong, independent of any community or contracts [Aristotle] |
Full Idea: There is something of which we all have an inkling, being a naturally universal right and wrong, even if there should be no community between the parties or contract. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1373b07) | |
A reaction: This is the strongest assertion I know of in Aristotle of an absolute moral standard, independent of natural function. It makes Aristotle an intuitionist, and is strikingly opposed to contracts as the most basic aspect of morality. |
5850 | Happiness is composed of a catalogue of internal and external benefits [Aristotle] |
Full Idea: The elements of happiness are: gentle birth, many virtuous friends, wealth, creditable and extensive offspring, a comfortable old age; also health, beauty, strength, size and competitiveness, reputation, status, luck and the virtues. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1360b18) | |
A reaction: This is Aristotle's pluralism, and his commitment to 'external goods' (rather than the inner good of pure virtue, which the Stoics preferred). 'Gentle birth' might turn out to mean good upbringing and education. Who was the most 'beautiful' philosopher? |
5856 | Self-interest is a relative good, but nobility an absolute good [Aristotle] |
Full Idea: One's own interest is a relative good, nobility a good absolutely. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1389b37) | |
A reaction: The key idea in the whole of Greek moral theory is the concept of what we can call a 'beautiful' action. Such things, or course, tend to be visible in great actions, such as sparing an enemy, rather than the minutiae of well-mannered daily life. |
5848 | All good things can be misused, except virtue [Aristotle] |
Full Idea: If one used strength, health, wealth and strategic expertise well, one might do the greatest possible good and if badly the greatest possible harm; this is a problem common to all good things, except virtue. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1355b04) | |
A reaction: Of course, this may just be a tautology about virtue, rather than an empirical observation. However, in 'Ethics' he tries to describe a state of mind (essentially one of harmony) which could never result in misuse. |
5853 | The best virtues are the most useful to others [Aristotle] |
Full Idea: The greatest virtues must be those most useful to others. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1366b02) | |
A reaction: I wonder if this applies to the intellectual virtues, as well as to the social virtues? Is this virtue theory's answer to utilitarianism, or utilitarianism's answer to virtue theory? Personally I think good persons are prior to benefits. |
5857 | The young feel pity from philanthropy, but the old from self-concern [Aristotle] |
Full Idea: Old men are prone to pity, but where the young are so from philanthropy, the old are so from weakness, for they think all these things are near for themselves to suffer. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1390a18) | |
A reaction: I am shocked to find Aristotle being so cynical. I see no reason why the old should not be as philanthropic as anyone else, and they clearly are so, as when they plant trees for future generations to enjoy. |
5859 | Rich people are mindlessly happy [Aristotle] |
Full Idea: The character of the rich man is that of the mindlessly happy one. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1391a12) | |
A reaction: Very nice. It is hard to deny that the rich tend to be happy (in some sense of the word), and recent sociological research has tended to demonstrate this, but the pursuit of wealth must inevitably take the focus away from key intellectual pursuits. Yeh? |
5852 | The four constitutions are democracy (freedom), oligarchy (wealth), aristocracy (custom), tyranny (security) [Aristotle] |
Full Idea: There are four types of constitution: democracy (whose purpose is freedom), oligarchy (for wealth), aristocracy (for education and customs), and monarch or tyranny (for security). | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1365b28-37) | |
A reaction: An aristocracy seems to be the guardians of tradition and culture (as in an English public school education). The tyranny of Hitler and Stalin did not exactly lead to security. Democracy and aristocracy are the front-runners. Compare Idea 2821. |
1660 | It is noble to avenge oneself on one's enemies, and not come to terms with them [Aristotle] |
Full Idea: It is noble to avenge oneself on one's enemies and not to come to terms with them. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1367a19), quoted by Gregory Vlastos - Socrates: Ironist and Moral Philosopher p.189 |
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 |
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. |
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) |
5861 | People assume events cause what follows them [Aristotle] |
Full Idea: Men take its occurring after as its occurring because. | |
From: Aristotle (The Art of Rhetoric [c.350 BCE], 1401b30) | |
A reaction: The Latin is 'post hoc propter hoc' - after this so because of this. It is quite a good inductive rule, but obviously open to abuse, as in legal cases, as when someone happens to acquire a lot of money just after a crime. |
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) |