74 ideas
1887 | You cannot divide anything into many parts, because after the first division you are no longer dividing the original [Sext.Empiricus] |
Full Idea: You cannot divide anything (such as the decad) into many parts, because as soon as you separate the first part, you are no longer dividing the original. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.215) |
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. |
1885 | Proof moves from agreed premises to a non-evident inference [Sext.Empiricus] |
Full Idea: Dogmatists define proof as "an argument which, by means of agreed premises, reveals by way of deduction a nonevident inference". | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.135) |
12196 | A valid hypothetical syllogism is 'that which does not begin with a truth and end with a falsehood' [Sext.Empiricus] |
Full Idea: Philo (of Megara) says that a valid hypothetical syllogism is 'that which does not begin with a truth and end with a falsehood,' as for instance the syllogism 'If it is day, I converse,' when in fact it is day and I am conversing. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.110) | |
A reaction: Russell endorses this, and Rumfitt quotes it as the classic case of denying that there is any modal aspect (such as 'logical necessity') involved in logical consequence. He labels it 'material or Philonian consequence'. |
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 |
1902 | Since Socrates either died when he was alive (a contradiction) or died when he was dead (meaningless), he didn't die [Sext.Empiricus] |
Full Idea: If Socrates died, he died either when he lived or when he died; so he was either dead when he was alive, or he was twice dead when he was dead. So he didn't die. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.111) | |
A reaction: One of my favourites. Of all the mysteries facing us, the one that boggles me most is how anything can happen in the 'present' moment, if the present is just the overlap point between past and future. |
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. |
18198 | Mathematics is part of science; transfinite mathematics I take as mostly uninterpreted [Quine] |
Full Idea: The mathematics wanted for use in empirical sciences is for me on a par with the rest of science. Transfinite ramifications are on the same footing as simplifications, but anything further is on a par rather with uninterpreted systems, | |
From: Willard Quine (Review of Parsons (1983) [1984], p.788), quoted by Penelope Maddy - Naturalism in Mathematics II.2 | |
A reaction: The word 'uninterpreted' is the interesting one. Would mathematicians object if the philosophers graciously allowed them to continue with their transfinite work, as long as they signed something to say it was uninterpreted? |
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) |
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) |
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) |
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) |
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) |
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) |
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. |
1889 | If an argument has an absurd conclusion, we should not assent to the absurdity, but avoid the absurd argument [Sext.Empiricus] |
Full Idea: If an argument leads to confessedly absurd conclusions, we should not assent to the absurdity just because of the argument, but avoid the argument because of the absurdity. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.252) | |
A reaction: cf. G.E.Moore. Denying that you have a hand seems to be an absurdity, but I'm not sure if I can give a criterion for absurdity in such a case. One person's modus ponens is another person's modus tollens. |
1871 | Whether honey is essentially sweet may be doubted, as it is a matter of judgement rather than appearance [Sext.Empiricus] |
Full Idea: Honey appears to sceptics to be sweet, but whether it is also sweet in its essence is for us a matter of doubt, since this is not an appearance but a judgement. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.20) |
1883 | How can the intellect know if sensation is reliable if it doesn't directly see external objects? [Sext.Empiricus] |
Full Idea: Just as you can't know if a portrait of Socrates is good without seeing the man, so when the intellect gazes on sensations but not the external objects it cannot know whether they are similar. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.75) |
1890 | We distinguish ambiguities by seeing what is useful [Sext.Empiricus] |
Full Idea: It is the experience of what is useful in each affair that brings about the distinguishing of ambiguities. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.258) |
1870 | The basis of scepticism is the claim that every proposition has an equal opposing proposition [Sext.Empiricus] |
Full Idea: The main basic principle of the sceptic system is that of opposing to every proposition an equal proposition. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.12) |
1882 | The necks of doves appear different in colour depending on the angle of viewing [Sext.Empiricus] |
Full Idea: The necks of doves appear different in hue according to the differences in the angle of inclination. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.120) |
1881 | The same oar seems bent in water and straight when out of it [Sext.Empiricus] |
Full Idea: The same oar seems bent when in the water but straight when out of the water. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.119) |
1872 | The same tower appears round from a distance, but square close at hand [Sext.Empiricus] |
Full Idea: The same tower appears round from a distance, but square close at hand. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.32) |
1873 | If we press the side of an eyeball, objects appear a different shape [Sext.Empiricus] |
Full Idea: When we press the eyeball at one side the forms, figures and sizes of the objects appear oblong and narrow. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.47) |
1874 | How can we judge between our impressions and those of other animals, when we ourselves are involved? [Sext.Empiricus] |
Full Idea: We cannot judge between our own impressions and those of other animals, because we ourselves are involved in the dispute. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.59) |
1878 | Water that seems lukewarm can seem very hot on inflamed skin [Sext.Empiricus] |
Full Idea: The same water which seems very hot when poured on inflamed spots seems lukewarm to us. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.101) |
1880 | Some actions seem shameful when sober but not when drunk [Sext.Empiricus] |
Full Idea: Actions which seem shameful to us when sober do not seem shameful when drunk. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.109) |
1877 | If we had no hearing or sight, we would assume no sound or sight exists, so there may be unsensed qualities [Sext.Empiricus] |
Full Idea: A man with touch, taste and smell, but no hearing or sight, will assume nothing audible or visible exists, so maybe an apple has qualities which we have no senses to perceive. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.96) |
1879 | Sickness is perfectly natural to the sick, so their natural perceptions should carry some weight [Sext.Empiricus] |
Full Idea: Health is natural for the healthy but unnatural for the sick, and sickness is unnatural for the healthy but natural for the sick, so we must give credence to the natural perceptions of the sick. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.103) |
1876 | If we enjoy different things, presumably we receive different impressions [Sext.Empiricus] |
Full Idea: The enjoyment of different things is an indication that we get varying impressions from the underlying objects. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.80) |
1911 | Even if all known nations agree on a practice, there may be unknown nations which disagree [Sext.Empiricus] |
Full Idea: Even among practices on which all known cultures are agreed, disagreement about them may possibly exist amongst some of the nations which are unknown to us. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.234) |
1910 | With us it is shameful for men to wear earrings, but among Syrians it is considered noble [Sext.Empiricus] |
Full Idea: It is a shameful thing with us for men to wear earrings, but among some of the barbarians, such as the Syrians, it is a token of nobility. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.203) |
1886 | If you don't view every particular, you may miss the one which disproves your universal induction [Sext.Empiricus] |
Full Idea: Induction cannot establish the universal by means of the particular, since limited particulars may omit crucial examples which disprove the universal, and infinite particulars are impossible to know. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.204) |
1884 | If we utter three steps of a logical argument, they never exist together [Sext.Empiricus] |
Full Idea: If we say "If day exists, lights exists", and then "day exists", and then "light exists", then parts of the judgement never exist together, and so the whole judgement will have no real existence. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.109) |
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. |
1894 | Some say that causes are physical, some say not [Sext.Empiricus] |
Full Idea: Some affirm cause to be corporeal, some incorporeal. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.14) |
1897 | Knowing an effect results from a cause means knowing that the cause belongs with the effect, which is circular [Sext.Empiricus] |
Full Idea: To know an effect belongs to a cause, we must also know that that cause belongs to that effect, and this is circular. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.21) |
1896 | If there were no causes then everything would have been randomly produced by everything [Sext.Empiricus] |
Full Idea: If causes were non-existent everything would have been produced by everything, and at random. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.18) |
1898 | Cause can't exist before effect, or exist at the same time, so it doesn't exist [Sext.Empiricus] |
Full Idea: If cause neither subsists before its effect, nor subsists along with it, nor does the effect precede the cause, it would seem that it has no substantial existence at all. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.27) |
1895 | Causes are either equal to the effect, or they link equally with other causes, or they contribute slightly [Sext.Empiricus] |
Full Idea: The majority say causes are immediate (when they are directly proportional to effects), or associate (making an equal contribution to effects), or cooperant (making a slight contribution). | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.15) |
1900 | If time and place are infinitely divided, it becomes impossible for movement ever to begin [Sext.Empiricus] |
Full Idea: If bodies, and the places and times when they are said to move, are divided into infinity, motion will not occur, it being impossible to find anything which will initiate the first movement. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.76) |
1901 | If all atoms, times and places are the same, everything should move with equal velocity [Sext.Empiricus] |
Full Idea: If objects are reducible to atoms, and each thing passes in an atomic time with its own first atom into an atomic point of space, then all moving things are of equal velocity. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.77) |
1899 | Does the original self-mover push itself from behind, or pull itself from in front? [Sext.Empiricus] |
Full Idea: Self-movement must move in some particular direction, but if it pushes it will be behind itself, and if it pulls it will be in front of itself. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.68) | |
A reaction: This is the same as Aquinas's First Way of proving God's existence. |
1903 | If motion and rest are abolished, so is time [Sext.Empiricus] |
Full Idea: Since time does not seem to subsist without motion or even rest, if motion is abolished, and likewise rest, time is abolished. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.141) |
1904 | Time must be unlimited, but past and present can't be non-existent, and can't be now, so time does not exist [Sext.Empiricus] |
Full Idea: There can't be a time when there was no time, so time is not limited; but unlimited time means past and present are non-existent (so time is limited to the present), or they exist (which means they are present). Time does not exist. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.142) |
1905 | How can time be divisible if we can't compare one length of time with another? [Sext.Empiricus] |
Full Idea: Time is clearly divisible (into past, present and future), but it can't be, because a divisible thing is measured by some part of itself (divisions of length), but the two parts must coincide to make the measurement (e.g. present must coincide with past). | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.143) |
1891 | How can we agree on the concept of God, unless we agree on his substance or form or place? [Sext.Empiricus] |
Full Idea: How shall we be able to reach a conception of God when we have no agreement about his substance or his form or his place of abode? | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.3) |
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) |
1892 | The existence of God can't be self-evident or everyone would have agreed on it, so it needs demonstration [Sext.Empiricus] |
Full Idea: The existence of God is not pre-evident, for if it was the dogmatists would have agreed about it, whereas their disagreements show it is non-evident, and in need of demonstration. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.6) |
1893 | If God foresaw evil he would presumably prevent it, and if he only foresees some things, why those things? [Sext.Empiricus] |
Full Idea: If God had forethought for all, there would be no evil in the world, yet they say the world is full of evil. And if he forethinks some things, why those and not others? | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.9) |