25 ideas
| 14179 | The finest branch of wisdom is justice and moderation in ordering states and families [Plato] |
| Full Idea: By far the greatest and fairest branch of wisdom is that which is concerned with the due ordering of states and families, whose name is moderation and justice. | |
| From: Plato (The Symposium [c.384 BCE], 209a) | |
| A reaction: ['Justice' is probably 'dikaiosune'] It is hard to disagree with this, and it relegates ivory tower philosophical contemplation to second place, unlike the late books of Aristotle's Ethics. |
| 15946 | Cantor developed sets from a progression into infinity by addition, multiplication and exponentiation [Cantor, by Lavine] |
| Full Idea: Cantor's development of set theory began with his discovery of the progression 0, 1, ....∞, ∞+1, ∞+2, ..∞x2, ∞x3, ...∞^2, ..∞^3, ...∞^∞, ...∞^∞^∞..... | |
| From: report of George Cantor (Grundlagen (Foundations of Theory of Manifolds) [1883]) by Shaughan Lavine - Understanding the Infinite VIII.2 |
| 15911 | Ordinals are generated by endless succession, followed by a limit ordinal [Cantor, by Lavine] |
| Full Idea: Ordinal numbers are generated by two principles: each ordinal has an immediate successor, and each unending sequence has an ordinal number as its limit (that is, an ordinal that is next after such a sequence). | |
| From: report of George Cantor (Grundlagen (Foundations of Theory of Manifolds) [1883]) by Shaughan Lavine - Understanding the Infinite III.4 |
| 10580 | Mathematics is both necessary and a priori because it really consists of logical truths [Yablo] |
| Full Idea: Mathematics seems necessary because the real contents of mathematical statements are logical truths, which are necessary, and it seems a priori because logical truths really are a priori. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 10) | |
| A reaction: Yablo says his logicism has a Kantian strain, because numbers and sets 'inscribed on our spectacles', but he takes a different view (in the present Idea) from Kant about where the necessity resides. Personally I am tempted by an a posteriori necessity. |
| 10579 | Putting numbers in quantifiable position (rather than many quantifiers) makes expression easier [Yablo] |
| Full Idea: Saying 'the number of Fs is 5', instead of using five quantifiers, puts the numeral in quantifiable position, which brings expressive advantages. 'There are more sheep in the field than cows' is an infinite disjunction, expressible in finite compass. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 08) | |
| A reaction: See Hofweber with similar thoughts. This idea I take to be a key one in explaining many metaphysical confusions. The human mind just has a strong tendency to objectify properties, relations, qualities, categories etc. - for expression and for reasoning. |
| 10577 | Concrete objects have few essential properties, but properties of abstractions are mostly essential [Yablo] |
| Full Idea: Objects like me have a few essential properties, and numerous accidental ones. Abstract objects are a different story. The intrinsic properties of the empty set are mostly essential. The relations of numbers are also mostly essential. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 01) |
| 10578 | We are thought to know concreta a posteriori, and many abstracta a priori [Yablo] |
| Full Idea: Our knowledge of concreta is a posteriori, but our knowledge of numbers, at least, has often been considered a priori. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 02) |
| 1607 | Diotima said the Forms are the objects of desire in philosophical discourse [Plato, by Roochnik] |
| Full Idea: According to Diotima, the Forms are the objects of desire operative in philosophical discourse. | |
| From: report of Plato (The Symposium [c.384 BCE], 210a4-) by David Roochnik - The Tragedy of Reason p.199 |
| 174 | True opinion without reason is midway between wisdom and ignorance [Plato] |
| Full Idea: There is a state of mind half-way between wisdom and ignorance - having true opinions without being able to give reasons for them. | |
| From: Plato (The Symposium [c.384 BCE], 202a) | |
| A reaction: Compare Idea 2140, where Plato scorns this state of mind. What he describes could be split into two - purely lucky true beliefs, and 'externalist knowledge', with non-conscious justification. |
| 181 | Only the gods stay unchanged; we replace our losses with similar acquisitions [Plato] |
| Full Idea: We retain identity not by staying the same (the preserve of gods) but by replacing losses with new similar acquisitions. | |
| From: Plato (The Symposium [c.384 BCE], 208b) | |
| A reaction: Any modern student of personal identity should be intrigued by this remark! It appears to take a rather physical view of the matter, and to be aware of human biology as a process. Are my continuing desires token-identical, or just 'similar'? |
| 180 | We call a person the same throughout life, but all their attributes change [Plato] |
| Full Idea: During the period from boyhood to old age, man does not retain the same attributes, though he is called the same person. | |
| From: Plato (The Symposium [c.384 BCE], 207d) | |
| A reaction: This precisely identifies the basic problem of personal identity over time. If this is the problem, DNA looks more and more significant for the answer, though it would be an awful mistake to think a pattern of DNA was a person. |
| 4026 | Beauty is harmony with what is divine, and ugliness is lack of such harmony [Plato] |
| Full Idea: Ugliness is out of harmony with everything that is godly; beauty, however, is in harmony with the divine. | |
| From: Plato (The Symposium [c.384 BCE], 206d) | |
| A reaction: This remark shows how the concept of 'harmony' is at the centre of Greek thought (and is a potential bridge of the is/ought gap). |
| 172 | Love of ugliness is impossible [Plato] |
| Full Idea: There cannot be such a thing as love of ugliness. | |
| From: Plato (The Symposium [c.384 BCE], 201a) |
| 173 | Beauty and goodness are the same [Plato] |
| Full Idea: What is good is the same as what is beautiful. | |
| From: Plato (The Symposium [c.384 BCE], 201c) |
| 183 | Stage two is the realisation that beauty of soul is of more value than beauty of body [Plato] |
| Full Idea: The second stage of progress is to realise that beauty of soul is more valuable than beauty of body. | |
| From: Plato (The Symposium [c.384 BCE], 210b) |
| 184 | Progress goes from physical beauty, to moral beauty, to the beauty of knowledge, and reaches absolute beauty [Plato] |
| Full Idea: One should step up from physical beauty, to moral beauty, to the beauty of knowledge, until at last one knows what absolute beauty is. | |
| From: Plato (The Symposium [c.384 BCE], 211c) | |
| A reaction: Presumably this is why Socrates refused sexual favours to Alcibiades. The idea is inspiring, and yet it is a rejection of humanity. |
| 171 | Music is a knowledge of love in the realm of harmony and rhythm [Plato] |
| Full Idea: Music may be called a knowledge of the principles of love in the realm of harmony and rhythm. | |
| From: Plato (The Symposium [c.384 BCE], 187c) |
| 176 | Love follows beauty, wisdom is exceptionally beautiful, so love follows wisdom [Plato] |
| Full Idea: Wisdom is one of the most beautiful of things, and Love is love of beauty, so it follows that Love must be a love of wisdom. | |
| From: Plato (The Symposium [c.384 BCE], 204b) | |
| A reaction: Good, but wisdom isn't the only exceptionally beautiful thing. Music is beautiful partly because it is devoid of ideas. |
| 14177 | Love assists men in achieving merit and happiness [Plato] |
| Full Idea: Phaedrus: Love is not only the oldest and most honourable of the gods, but also the most powerful to assist men in the acquisition of merit and happiness, both here and hereafter. | |
| From: Plato (The Symposium [c.384 BCE], 180b) | |
| A reaction: Maybe we should talk less of love as a feeling, and more as a motivation, not just in human relationships, but in activities like gardening and database compilation. |
| 179 | Love is desire for perpetual possession of the good [Plato] |
| Full Idea: Love is desire for perpetual possession of the good. | |
| From: Plato (The Symposium [c.384 BCE], 206a) | |
| A reaction: Even the worst human beings often have lovers. 'Perpetual' is a nice observation. |
| 177 | If a person is good they will automatically become happy [Plato] |
| Full Idea: 'What will be gained by a man who is good?' 'That is easy - he will be happy'. | |
| From: Plato (The Symposium [c.384 BCE], 205a) | |
| A reaction: Suppose you tried to assassinate Hitler in 1944 (a good deed), but failed. Happiness presumably results from success, rather than mere good intentions. |
| 14178 | Happiness is secure enjoyment of what is good and beautiful [Plato] |
| Full Idea: By happy you mean in secure enjoyment of what is good and beautiful? - Certainly. | |
| From: Plato (The Symposium [c.384 BCE], 202c) | |
| A reaction: We seem to have lost track of the idea that beauty might be an essential ingredient of happiness. |
| 170 | The only slavery which is not dishonourable is slavery to excellence [Plato] |
| Full Idea: The only form of servitude which has no dishonour has for its object the acquisition of excellence. | |
| From: Plato (The Symposium [c.384 BCE], 184c) |
| 182 | The first step on the right path is the contemplation of physical beauty when young [Plato] |
| Full Idea: The man who would pursue the right way to his goal must begin, when he is young, by contemplating physical beauty. | |
| From: Plato (The Symposium [c.384 BCE], 210a) |
| 175 | Gods are not lovers of wisdom, because they are already wise [Plato] |
| Full Idea: No god is a lover of wisdom or desires to be wise, for he is wise already. | |
| From: Plato (The Symposium [c.384 BCE], 204a) |