15 ideas
192 | Only one thing can be contrary to something [Plato] |
Full Idea: To everything that admits of a contrary there is one contrary and no more. | |
From: Plato (Protagoras [c.380 BCE], 332c) | |
A reaction: The sort of thing for which a modern philosopher would demand a proof (and then reject when the proof couldn't be found), where a Greek is happy to assert it as self-evident. I can't think of a counterexample. |
7726 | Aristotelian logic dealt with inferences about concepts, and there were also proposition inferences [Weiner] |
Full Idea: Till the nineteenth century, it was a common view that Aristotelian logic could evaluate inferences whose validity was based on relations between concepts, while propositional logic could evaluate inferences based on relations between propositions. | |
From: Joan Weiner (Frege [1999], Ch.3) | |
A reaction: Venn diagrams relate closely to Aristotelian syllogisms, as each concept is represented by a circle, and shows relations between sets. Arrows seem needed to represent how to go from one proposition to another. Is one static, the other dynamic? |
190 | If asked whether justice itself is just or unjust, you would have to say that it is just [Plato] |
Full Idea: If someone asked me 'Is justice itself just or unjust?' I should answer that it was just, wouldn't you? I agree. | |
From: Plato (Protagoras [c.380 BCE], 330c) |
20185 | The most important things in life are wisdom and knowledge [Plato] |
Full Idea: It would be shameful indeed to say that wisdom and knowledge are anything but the most powerful forces in human activity. | |
From: Plato (Protagoras [c.380 BCE], 352d) | |
A reaction: He lumps wisdom and knowledge together, and I think we can take 'knowledge' to mean something like understanding, because obviously mere atomistic propositional knowledge can be utterly trivial. |
20184 | The only real evil is loss of knowledge [Plato] |
Full Idea: The only real kind of faring ill is the loss of knowledge. | |
From: Plato (Protagoras [c.380 BCE], 345b) | |
A reaction: This must crucially involve the intellectualist view (of Socrates) that virtuos behaviour results from knowledge, and moral wickedness is the result of ignorance. It is hard to see how forgetting a phone number is evil. |
191 | Everything resembles everything else up to a point [Plato] |
Full Idea: Everything resembles everything else up to a point. | |
From: Plato (Protagoras [c.380 BCE], 331d) |
203 | Courage is knowing what should or shouldn't be feared [Plato] |
Full Idea: Knowledge of what is and is not to be feared is courage. | |
From: Plato (Protagoras [c.380 BCE], 360d) |
202 | No one willingly and knowingly embraces evil [Plato] |
Full Idea: No one willingly goes to meet evil, or what he thinks is evil. | |
From: Plato (Protagoras [c.380 BCE], 358d) | |
A reaction: Presumably people who actively choose satanism can override this deep-seated attitude. But their adherence to evil usually seems to be rather restrained. A danger of tautology with ideas like this. |
193 | Some things are good even though they are not beneficial to men [Plato] |
Full Idea: 'Do you mean by good those things that are beneficial to men?' 'Not only those. I call some things which are not beneficial good as well'. | |
From: Plato (Protagoras [c.380 BCE], 333e) | |
A reaction: Examples needed, but this would be bad news for utilitarians. Good health is not seen as beneficial if it is taken for granted. Not being deaf. |
197 | Some pleasures are not good, and some pains are not evil [Plato] |
Full Idea: There are some pleasures which are not good, and some pains which are not evil. | |
From: Plato (Protagoras [c.380 BCE], 351d) | |
A reaction: Sadism and child birth. Though Bentham (I think) says that there is nothing good about the pain, since the event would obviously be better without it. |
200 | People tend only to disapprove of pleasure if it leads to pain, or prevents future pleasure [Plato] |
Full Idea: The only reason the common man disapproves of pleasures is if they lead to pain and deprive us of future pleasures. | |
From: Plato (Protagoras [c.380 BCE], 354a) | |
A reaction: Plato has a strong sense that some pleasures are just innately depraved and wicked. If those pleasure don't hurt anyone, it is very hard to pinpoint what is wrong with them. |
188 | Socrates did not believe that virtue could be taught [Plato] |
Full Idea: Socrates: I do not believe that virtue can be taught. | |
From: Plato (Protagoras [c.380 BCE], 320b) |
204 | Socrates is contradicting himself in claiming virtue can't be taught, but that it is knowledge [Plato] |
Full Idea: Socrates is contradicting himself by saying virtue is not teachable, and yet trying to demonstrate that every virtue is knowledge. | |
From: Plato (Protagoras [c.380 BCE], 361b) |
189 | If we punish wrong-doers, it shows that we believe virtue can be taught [Plato] |
Full Idea: Athenians inflict punishment on wrong-doers, which shows that they too think it possible to impart and teach goodness. | |
From: Plato (Protagoras [c.380 BCE], 324c) |
20486 | Only liberty, equality and sympathy can stand up to anti-social people [Kropotkin] |
Full Idea: Liberty, equality and practical human sympathy are the only effective barriers we can oppose to the anti-social instincts of certain among us. | |
From: Peter (Pyotr) Kropotkin (Law and Authority [1886], 1 'Anarchism'), quoted by Jonathan Wolff - An Introduction to Political Philosophy (Rev) | |
A reaction: One might state it more succinctly as 'only the social can oppose the anti-social'. The dominance in society of essentially anti-social people seems to have become a major political fact in 2017, in the UK and the USA. |