22 ideas
| 8964 | Entities can be multiplied either by excessive categories, or excessive entities within a category [Hoffman/Rosenkrantz] |
| Full Idea: There are two ways that entities can be multiplied unnecessarily: by multiplying the number of explanatory categories, and by multiplying the number of entities within a category. | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 4) | |
| A reaction: An important distinction. The orthodox view is that it is the excess of categories that is to be avoided (e.g. by nominalists). Possible worlds in metaphysics, and multiple worlds in physics, claim not to violate the first case. |
| 1553 | No perceptible object is truly straight or curved [Protagoras] |
| Full Idea: No perceptible object is geometrically straight or curved; after all, a circle does not touch a ruler at a point, as Protagoras used to say, in arguing against the geometers. | |
| From: Protagoras (fragments/reports [c.441 BCE], B07), quoted by Aristotle - Metaphysics 998a1 |
| 8962 | 'There are shapes which are never exemplified' is the toughest example for nominalists [Hoffman/Rosenkrantz] |
| Full Idea: The example which presents the most serious challenge to nominalism is 'there are shapes which are never exemplified'. | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 3) | |
| A reaction: To 'exemplify' a shape must it be a physical object, or a drawing of such an object, or a description? If none of those have ever existed, I'm not sure what 'are' is supposed to mean. They seem to be possibilia (with all the associated problems). |
| 8961 | Nominalists are motivated by Ockham's Razor and a distrust of unobservables [Hoffman/Rosenkrantz] |
| Full Idea: The two main motivations for nominalism are an admirable commitment to Ockham's Razor, and a queasiness about postulating entities that are unobservable or non-empirical, existing in a non-physical realm. | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 3) | |
| A reaction: It doesn't follow that because the entities are unobservable that they are non-physical. Consider the 'interior' of an electron. Neverless I share a love of Ockham's Razor and a deep caution about unobservables. |
| 8963 | Four theories of possible worlds: conceptualist, combinatorial, abstract, or concrete [Hoffman/Rosenkrantz] |
| Full Idea: There are four models of the ontological status of possible worlds: conceptualist (mental constructions), combinatorial (all combinations of the actual world), abstract worlds (conjunction of propositions), and concrete worlds (collections of concreta). | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 4) | |
| A reaction: [the proponents cited are, in order, Rescher, Cresswell, Plantinga and Lewis] They dismiss Rescher and Cresswell, both of whom seem to me more plausible than Plantinga or Lewis. 'Possible' can't figure in the definition. Possible to us, or in reality? |
| 1549 | Everything that exists consists in being perceived [Protagoras] |
| Full Idea: Everything that exists consists in being perceived. | |
| From: Protagoras (fragments/reports [c.441 BCE]), quoted by Didymus the Blind - Commentary on the Psalms (frags) | |
| A reaction: A striking anticipation of Berkeley's "esse est percipi" (to be is to be perceived). |
| 1545 | Protagoras was the first to claim that there are two contradictory arguments about everything [Protagoras, by Diog. Laertius] |
| Full Idea: Protagoras was the first to claim that there are two contradictory arguments about everything. | |
| From: report of Protagoras (fragments/reports [c.441 BCE], A01) by Diogenes Laertius - Lives of Eminent Philosophers 09.51 |
| 1547 | Man is the measure of all things - of things that are, and of things that are not [Protagoras] |
| Full Idea: He began one of his books as follows: 'Man is the measure of all things - of the things that are, that they are, and of the things that are not, that they are not'. | |
| From: Protagoras (fragments/reports [c.441 BCE], B01), quoted by Diogenes Laertius - Lives of Eminent Philosophers 09.51 |
| 3305 | There is no more purely metaphysical doctrine than Protagorean relativism [Benardete,JA on Protagoras] |
| Full Idea: No purer metaphysical doctrine can possibly be found than the Protagorean thesis that to be (anything at all) is to be relative ( to something or other). | |
| From: comment on Protagoras (fragments/reports [c.441 BCE]) by José A. Benardete - Metaphysics: the logical approach Ch.3 |
| 3317 | You can only state the problem of the relative warmth of an object by agreeing on the underlying object [Benardete,JA on Protagoras] |
| Full Idea: Only if the thing that is cold to me is precisely identical with the thing that is not cold to you can Protagoras launch his argument, but then it is seen to be the thing in itself that exists absolutely speaking. | |
| From: comment on Protagoras (fragments/reports [c.441 BCE]) by José A. Benardete - Metaphysics: the logical approach Ch.8 |
| 3313 | If my hot wind is your cold wind, then wind is neither hot nor cold, and so not as cold as itself [Benardete,JA on Protagoras] |
| Full Idea: Because the wind is cold to me but not you, Protagoras takes it to in itself neither cold nor not-cold. Accordingly, I very much doubt that he can allow the wind to be exactly as cold as itself. | |
| From: comment on Protagoras (fragments/reports [c.441 BCE]) by José A. Benardete - Metaphysics: the logical approach Ch.8 |
| 247 | God is "the measure of all things", more than any man [Plato on Protagoras] |
| Full Idea: In our view it is God who is pre-eminently the "measure of all things", much more so than any "man", as they say. | |
| From: comment on Protagoras (fragments/reports [c.441 BCE]) by Plato - The Laws 716c |
| 606 | Protagoras absurdly thought that the knowing or perceiving man is 'the measure of all things' [Aristotle on Protagoras] |
| Full Idea: When Protagoras quipped that man is the measure of all things, he had in mind, of course, the knowing or perceiving man. The grounds are that they have perception/knowledge, and these are said to be the measures of objects. Utter nonsense! | |
| From: comment on Protagoras (fragments/reports [c.441 BCE]) by Aristotle - Metaphysics 1053b |
| 612 | Relativists think if you poke your eye and see double, there must be two things [Aristotle on Protagoras] |
| Full Idea: In fact there is no difference between Protagoreanism and saying this: if you stick your finger under your eyes and make single things seem two, then they are two, just because they seem to be two. | |
| From: comment on Protagoras (fragments/reports [c.441 BCE]) by Aristotle - Metaphysics 1063a06 |
| 6016 | Early sophists thought convention improved nature; later they said nature was diminished by it [Protagoras, by Miller,FD] |
| Full Idea: Protagoras and Hippias evidently believed that convention was an improvement on nature, whereas later sophists such as Antiphon, Thrasymachus and Callicles seemed to contend that conventional morality was undermined because it was 'against nature'. | |
| From: report of Protagoras (fragments/reports [c.441 BCE]) by Fred D. Miller jr - Classical Political Thought | |
| A reaction: This gets to the heart of a much more interesting aspect of the nomos-physis (convention-nature) debate, rather than just a slanging match between relativists and the rest. The debate still goes on, over issues about the free market and intervention. |
| 1580 | For Protagoras the only bad behaviour is that which interferes with social harmony [Protagoras, by Roochnik] |
| Full Idea: For Protagoras the only constraint on human behaviour is that it not interfere with social harmony, the essential condition for human survival. | |
| From: report of Protagoras (fragments/reports [c.441 BCE]) by David Roochnik - The Tragedy of Reason p.63 |
| 205 | Protagoras contradicts himself by saying virtue is teachable, but then that it is not knowledge [Plato on Protagoras] |
| Full Idea: Protagoras claimed that virtue was teachable, but now tries to show it is not knowledge, which makes it less likely to be teachable. | |
| From: comment on Protagoras (fragments/reports [c.441 BCE]) by Plato - Protagoras 361b |
| 1659 | Protagoras seems to have made the huge move of separating punishment from revenge [Protagoras, by Vlastos] |
| Full Idea: The distinction of punishment from revenge must be regarded as one of the most momentous of the conceptual discoveries ever made by humanity in the course of its slow, tortuous, precarious, emergence from barbaric tribalism. Protagoras originated it. | |
| From: report of Protagoras (fragments/reports [c.441 BCE]) by Gregory Vlastos - Socrates: Ironist and Moral Philosopher p.187 |
| 532 | Successful education must go deep into the soul [Protagoras] |
| Full Idea: Education does not take root in the soul unless one goes deep. | |
| From: Protagoras (fragments/reports [c.441 BCE], B11), quoted by Plutarch - On Practice 178.25 |
| 1552 | He spent public money on education, as it benefits the individual and the state [Protagoras, by Diodorus of Sicily] |
| Full Idea: He used legislation to improve the condition of illiterate people, on the grounds that they lack one of life's great goods, and thought literacy should be a matter of public concern and expense. | |
| From: report of Protagoras (fragments/reports [c.441 BCE]) by Diodorus of Sicily - Universal History 12.13.3.3 |
| 1551 | He said he didn't know whether there are gods - but this is the same as atheism [Diogenes of Oen. on Protagoras] |
| Full Idea: He said that he did not know whether there were gods - but this is the same as saying that he knew there were no gods. | |
| From: comment on Protagoras (fragments/reports [c.441 BCE], A23) by Diogenes (Oen) - Wall inscription 11 Chil 2 |
| 1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |
| Full Idea: The Egyptians were the first to claim that the soul of a human being is immortal, and that each time the body dies the soul enters another creature just as it is being born. | |
| From: Herodotus (The Histories [c.435 BCE], 2.123.2) |