24 ideas
| 1708 | In "Callias is just/not just/unjust", which of these are contraries? [Aristotle] |
| Full Idea: Take, for example, "Callias is just", "Callias is not just", and "Callias is unjust"; which of these are contraries? | |
| From: Aristotle (On Interpretation [c.330 BCE], 23a31) |
| 1703 | It is necessary that either a sea-fight occurs tomorrow or it doesn't, though neither option is in itself necessary [Aristotle] |
| Full Idea: It is not necessary for a sea-battle to take place tomorrow, nor for one not to take place tomorrow - though it is necessary for one to take place OR not take place tomorrow. | |
| From: Aristotle (On Interpretation [c.330 BCE], 19a30) |
| 1704 | Statements are true according to how things actually are [Aristotle] |
| Full Idea: Statements are true according to how things actually are. | |
| From: Aristotle (On Interpretation [c.330 BCE], 19a33) |
| 22272 | Aristotle's later logic had to treat 'Socrates' as 'everything that is Socrates' [Potter on Aristotle] |
| Full Idea: When Aristotle moved from basic name+verb (in 'De Interpretatione') to noun+noun logic...names had to be treated as special cases, so that 'Socrates' is treated as short for 'everything that is Socrates'. | |
| From: comment on Aristotle (On Interpretation [c.330 BCE]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 02 'Supp' | |
| A reaction: Just the sort of rewriting that Russell introduced for definite descriptions. 'Twas ever the logicians' fate to shoehorn ordinary speech into awkward containers. |
| 9405 | Square of Opposition: not both true, or not both false; one-way implication; opposite truth-values [Aristotle] |
| Full Idea: Square of Opposition: horizontals - 'contraries' can't both be true, and 'subcontraries' can't both be false; verticals - 'subalternatives' have downwards-only implication; diagonals - 'contradictories' have opposite truth values. | |
| From: Aristotle (On Interpretation [c.330 BCE], Ch.12-13) | |
| A reaction: This is still used in modern discussion (e.g. by Stalnaker against Kripke), and there is a modal version of it (Fitting and Mendelsohn p.7). Corners read: 'All F are G', 'No F are G', 'Some F are G' and 'Some F are not G'. |
| 9728 | Modal Square 1: □P and ¬◊¬P are 'contraries' of □¬P and ¬◊P [Aristotle, by Fitting/Mendelsohn] |
| Full Idea: Modal Square of Opposition 1: 'It is necessary that P' and 'It is not possible that not P' are the contraries (not both true) of 'It is necessary that not P' and 'It is not possible that P'. | |
| From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12a) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4 |
| 9729 | Modal Square 2: ¬□¬P and ◊P are 'subcontraries' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn] |
| Full Idea: Modal Square of Opposition 2: 'It is not necessary that not P' and 'It is possible that P' are the subcontraries (not both false) of 'It is not necessary that P' and 'It is possible that not P'. | |
| From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12b) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4 |
| 9730 | Modal Square 3: □P and ¬◊¬P are 'contradictories' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn] |
| Full Idea: Modal Square of Opposition 3: 'It is necessary that P' and 'It is not possible that not P' are the contradictories (different truth values) of 'It is not necessary that P' and 'It is possible that not P'. | |
| From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12c) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4 |
| 9731 | Modal Square 4: □¬P and ¬◊P are 'contradictories' of ¬□¬P and ◊P [Aristotle, by Fitting/Mendelsohn] |
| Full Idea: Modal Square of Opposition 4: 'It is necessary that not P' and 'It is not possible that P' are the contradictories (different truth values) of 'It is not necessary that not P' and 'It is possible that P'. | |
| From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12d) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4 |
| 9732 | Modal Square 5: □P and ¬◊¬P are 'subalternatives' of ¬□¬P and ◊P [Aristotle, by Fitting/Mendelsohn] |
| Full Idea: Modal Square of Opposition 5: 'It is necessary that P' and 'It is not possible that not P' are the subalternatives (first implies second) of 'It is not necessary that not P' and 'It is possible that P'. | |
| From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12e) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4 |
| 9733 | Modal Square 6: □¬P and ¬◊P are 'subalternatives' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn] |
| Full Idea: Modal Square of Opposition 6: 'It is necessary that not P' and 'It is not possible that P' are the subalternatives (first implies second) of 'It is not necessary that P' and 'It is possible that not P'. | |
| From: report of Aristotle (On Interpretation [c.330 BCE], Ch.12f) by M Fitting/R Mendelsohn - First-Order Modal Logic 1.4 |
| 21593 | In talking of future sea-fights, Aristotle rejects bivalence [Aristotle, by Williamson] |
| Full Idea: Unlike Aristotle, Stoics did not reject Bivalence for future contingencies; it is true or false that there will be a sea-fight tomorrow. | |
| From: report of Aristotle (On Interpretation [c.330 BCE], 19a31) by Timothy Williamson - Vagueness 1.2 | |
| A reaction: I'd never quite registered this simple account of the sea-fight. As Williamson emphasises, one should not lightly reject the principle of bivalence. Has Aristotle entered a slippery slope? Stoics disagreed with Aristotle. |
| 1701 | A prayer is a sentence which is neither true nor false [Aristotle] |
| Full Idea: A prayer is a sentence which is neither true nor false. | |
| From: Aristotle (On Interpretation [c.330 BCE], 17a01) |
| 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. |
| 1706 | Non-existent things aren't made to exist by thought, because their non-existence is part of the thought [Aristotle] |
| Full Idea: It is not true to say that what is not, since it is thought about, is something that is; for what is thought about it is not that it is, but that it is not. | |
| From: Aristotle (On Interpretation [c.330 BCE], 21a31) | |
| A reaction: At least there has been one philosopher who was quite clear about the distinction between a thought and what the thought is about (its content). Often forgotten! |
| 1707 | Maybe necessity and non-necessity are the first principles of ontology [Aristotle] |
| Full Idea: Perhaps the necessary and non-necessary are first principles of everything's either being or not being. | |
| From: Aristotle (On Interpretation [c.330 BCE], 23a18) |
| 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) |
| 2337 | For Aristotle meaning and reference are linked to concepts [Aristotle, by Putnam] |
| Full Idea: In 'De Interpretatione' Aristotle laid out an enduring theory of reference and meaning, in which we understand a word or any other sign by associating that word with a concept. This concept determines what the word refers to. | |
| From: report of Aristotle (On Interpretation [c.330 BCE]) by Hilary Putnam - Representation and Reality 2 p.19 | |
| A reaction: Sounds right to me, despite all this Wittgensteinian stuff about beetles in boxes. When you meet a new technical term in philosophy, you must struggle to fully grasp the concept it proposes. |
| 13763 | Spoken sounds vary between people, but are signs of affections of soul, which are the same for all [Aristotle] |
| Full Idea: Spoken sounds are symbols of affections in the soul, ...and just as written marks are not the same for all men, neither are spoken sounds. But what these are in the first place signs of - affections of the soul - are the same for all. | |
| From: Aristotle (On Interpretation [c.330 BCE], 16a03-08) | |
| A reaction: Loux identifies this passage as the source of the 'conceptualist' view of propositions, which I immediately identify with. The view that these propositions are 'the same for all' is plausible for normal objects, but dubious for complex abstractions. |
| 1705 | It doesn't have to be the case that in opposed views one is true and the other false [Aristotle] |
| Full Idea: It is not necessary that of every affirmation and opposite negation one should be true and the other false. For what holds for things that are does not hold for things that are not but may possibly be or not be. | |
| From: Aristotle (On Interpretation [c.330 BCE], 19a39) | |
| A reaction: Thus even if Bivalence holds, and the only truth-values are T and F, it doesn't follow that Excluded Middle holds, which says that every proposition must have one of those two values. |
| 1702 | Things may be necessary once they occur, but not be unconditionally necessary [Aristotle] |
| Full Idea: To say that everything that is, is of necessity, when it is, is not the same as saying unconditionally that it is of necessity. | |
| From: Aristotle (On Interpretation [c.330 BCE], 19a25) |
| 20698 | Irenaeus says evil is necessary for perfect human development [Irenaeus, by Davies,B] |
| Full Idea: Echoing Irenaeus, John Hick argues that the existence of evil is necessary for the perfect development of human beings. Hick understands evil in the light of God's desire not to coerce people into accepting him. | |
| From: report of Irenaeus (works [c.190]) by Brian Davies - Introduction to the Philosophy of Religion 3 'Notable' | |
| A reaction: I don't suppose I could opt out of perfect development? If I endure the evil, can I be guaranteed that my development will be 'perfect'. Oh, and could I just check what is meant by 'development'? |