45 ideas
| 501 | Reason is a more powerful persuader than gold [Democritus (attr)] |
| Full Idea: In power of persuasion, reasoning is far stronger than gold. | |
| From: Democritus (attrib) (reports [c.250 BCE], B051), quoted by John Stobaeus - Anthology 2.04.12 |
| 13838 | A decent modern definition should always imply a semantics [Hacking] |
| Full Idea: Today we expect that anything worth calling a definition should imply a semantics. | |
| From: Ian Hacking (What is Logic? [1979], §10) | |
| A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives. |
| 15647 | Truth definitions don't produce a good theory, because they go beyond your current language [Halbach] |
| Full Idea: It is far from clear that a definition of truth can lead to a philosophically satisfactory theory of truth. Tarski's theorem on the undefinability of the truth predicate needs resources beyond those of the language for which it is being defined. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1) | |
| A reaction: The idea is that you need a 'metalanguage' for the definition. If I say 'p' is a true sentence in language 'L', I am not making that observation from within language L. The dream is a theory confined to the object language. |
| 15649 | In semantic theories of truth, the predicate is in an object-language, and the definition in a metalanguage [Halbach] |
| Full Idea: In semantic theories of truth (Tarski or Kripke), a truth predicate is defined for an object-language. This definition is carried out in a metalanguage, which is typically taken to include set theory or another strong theory or expressive language. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1) | |
| A reaction: Presumably the metalanguage includes set theory because that connects it with mathematics, and enables it to be formally rigorous. Tarski showed, in his undefinability theorem, that the meta-language must have increased resources. |
| 15655 | Should axiomatic truth be 'conservative' - not proving anything apart from implications of the axioms? [Halbach] |
| Full Idea: If truth is not explanatory, truth axioms should not allow proof of new theorems not involving the truth predicate. It is hence said that axiomatic truth should be 'conservative' - not implying further sentences beyond what the axioms can prove. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1.3) | |
| A reaction: [compressed] |
| 15654 | If truth is defined it can be eliminated, whereas axiomatic truth has various commitments [Halbach] |
| Full Idea: If truth can be explicitly defined, it can be eliminated, whereas an axiomatized notion of truth may bring all kinds of commitments. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1.3) | |
| A reaction: The general principle that anything which can be defined can be eliminated (in an abstract theory, presumably, not in nature!) raises interesting questions about how many true theories there are which are all equivalent to one another. |
| 15648 | Instead of a truth definition, add a primitive truth predicate, and axioms for how it works [Halbach] |
| Full Idea: The axiomatic approach does not presuppose that truth can be defined. Instead, a formal language is expanded by a new primitive predicate of truth, and axioms for that predicate are then laid down. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1) | |
| A reaction: Idea 15647 explains why Halbach thinks the definition route is no good. |
| 15650 | Axiomatic theories of truth need a weak logical framework, and not a strong metatheory [Halbach] |
| Full Idea: Axiomatic theories of truth can be presented within very weak logical frameworks which require very few resources, and avoid the need for a strong metalanguage and metatheory. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1) |
| 15656 | Deflationists say truth merely serves to express infinite conjunctions [Halbach] |
| Full Idea: According to many deflationists, truth serves merely the purpose of expressing infinite conjunctions. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1.3) | |
| A reaction: That is, it asserts sentences that are too numerous to express individually. It also seems, on a deflationist view, to serve for anaphoric reference to sentences, such as 'what she just said is true'. |
| 13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
| Full Idea: 'Dilution' (or 'Thinning') provides an essential contrast between deductive and inductive reasoning; for the introduction of new premises may spoil an inductive inference. | |
| From: Ian Hacking (What is Logic? [1979], §06.2) | |
| A reaction: That is, inductive logic (if there is such a thing) is clearly non-monotonic, whereas classical inductive logic is monotonic. |
| 13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
| Full Idea: If A |- B and B |- C, then A |- C. This generalises to: If Γ|-A,Θ and Γ,A |- Θ, then Γ |- Θ. Gentzen called this 'cut'. It is the transitivity of a deduction. | |
| From: Ian Hacking (What is Logic? [1979], §06.3) | |
| A reaction: I read the generalisation as 'If A can be either a premise or a conclusion, you can bypass it'. The first version is just transitivity (which by-passes the middle step). |
| 13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
| Full Idea: Only the cut rule can have a conclusion that is less complex than its premises. Hence when cut is not used, a derivation is quite literally constructive, building up from components. Any theorem obtained by cut can be obtained without it. | |
| From: Ian Hacking (What is Logic? [1979], §08) |
| 15657 | To prove the consistency of set theory, we must go beyond set theory [Halbach] |
| Full Idea: The consistency of set theory cannot be established without assumptions transcending set theory. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 2.1) |
| 13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
| Full Idea: I don't believe English is by nature classical or intuitionistic etc. These are abstractions made by logicians. Logicians attend to numerous different objects that might be served by 'If...then', like material conditional, strict or relevant implication. | |
| From: Ian Hacking (What is Logic? [1979], §15) | |
| A reaction: The idea that they are 'abstractions' is close to my heart. Abstractions from what? Surely 'if...then' has a standard character when employed in normal conversation? |
| 13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
| Full Idea: First-order logic is the strongest complete compact theory with a Löwenheim-Skolem theorem. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
| Full Idea: Henkin proved that there is no first-order treatment of branching quantifiers, which do not seem to involve any idea that is fundamentally different from ordinary quantification. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: See Hacking for an example of branching quantifiers. Hacking is impressed by this as a real limitation of the first-order logic which he generally favours. |
| 13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
| Full Idea: Second-order logic has no chance of a completeness theorem unless one ventures into intensional entities and possible worlds. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 15652 | We can use truth instead of ontologically loaded second-order comprehension assumptions about properties [Halbach] |
| Full Idea: The reduction of 2nd-order theories (of properties or sets) to axiomatic theories of truth may be conceived as a form of reductive nominalism, replacing existence assumptions (for comprehension axioms) by ontologically innocent truth assumptions. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1.1) | |
| A reaction: I like this very much, as weeding properties out of logic (without weeding them out of the world). So-called properties in logic are too abundant, so there is a misfit with their role in science. |
| 13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
| Full Idea: My doctrine is that the peculiarity of the logical constants resides precisely in that given a certain pure notion of truth and consequence, all the desirable semantic properties of the constants are determined by their syntactic properties. | |
| From: Ian Hacking (What is Logic? [1979], §09) | |
| A reaction: He opposes this to Peacocke 1976, who claims that the logical connectives are essentially semantic in character, concerned with the preservation of truth. |
| 13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
| Full Idea: For some purposes the variables of first-order logic can be regarded as prepositions and place-holders that could in principle be dispensed with, say by a system of arrows indicating what places fall in the scope of which quantifier. | |
| From: Ian Hacking (What is Logic? [1979], §11) | |
| A reaction: I tend to think of variables as either pronouns, or as definite descriptions, or as temporary names, but not as prepositions. Must address this new idea... |
| 15651 | Instead of saying x has a property, we can say a formula is true of x - as long as we have 'true' [Halbach] |
| Full Idea: Quantification over (certain) properties can be mimicked in a language with a truth predicate by quantifying over formulas. Instead of saying that Tom has the property of being a poor philosopher, we can say 'x is a poor philosopher' is true of Tom. | |
| From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1.1) | |
| A reaction: I love this, and think it is very important. He talks of 'mimicking' properties, but I see it as philosophers mistakenly attributing properties, when actually what they were doing is asserting truths involving certain predicates. |
| 13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
| Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos. |
| 514 | Beauty is merely animal without intelligence [Democritus (attr)] |
| Full Idea: Physical beauty is merely animal unless intelligence be present. | |
| From: Democritus (attrib) (reports [c.250 BCE], B105) |
| 525 | Behave well when alone, and feel shame in you own eyes [Democritus (attr)] |
| Full Idea: Do not say or do what is base, even when you are alone. Learn to feel shame in your own eyes much more than before others. | |
| From: Democritus (attrib) (reports [c.250 BCE], B244), quoted by John Stobaeus - Anthology 3.31.7 | |
| A reaction: I like this. How you think and behave when unobserved is the true test of who you are. Feeling shame at a very private failing is an interesting phenomenon. |
| 502 | Good breeding in men means having a good character [Democritus (attr)] |
| Full Idea: Good breeding in cattle depends on physical health, but in men on a well-formed character. | |
| From: Democritus (attrib) (reports [c.250 BCE], B057), quoted by John Stobaeus - Anthology 4.29.18 | |
| A reaction: In our ultra-democratic age (supposedly) it is heresy to talk about good breeding, or some people being superior to others. But surely people should aim to improve their characters? |
| 507 | Virtuous love consists of decorous desire for the beautiful [Democritus (attr)] |
| Full Idea: Virtuous love consists of decorous desire for the beautiful. | |
| From: Democritus (attrib) (reports [c.250 BCE], B073), quoted by John Stobaeus - Anthology 3.5.23 | |
| A reaction: Is it possible to love something without seeing it as beautiful? A badly crippled dog, for example. If not, that seems to reveal something about beauty. |
| 521 | We should only choose pleasures which are concerned with the beautiful [Democritus (attr)] |
| Full Idea: One should choose not every pleasure, but only that concerned with the beautiful. | |
| From: Democritus (attrib) (reports [c.250 BCE], B207), quoted by John Stobaeus - Anthology 3.05.22 | |
| A reaction: The pleasures we should prefer are those which involve the whole person, rather than the mere stimulation of one sense. Sez me. |
| 505 | Good and true are the same for everyone, but pleasures differ [Democritus (attr)] |
| Full Idea: For all men, good and true are the same; but pleasant differs for different men. | |
| From: Democritus (attrib) (reports [c.250 BCE], B069) | |
| A reaction: Truth is not 'for' anyone, but there's good-in-itself, and good-for-me. Are there some pleasures we should all enjoy (such as watching our children flourish)? |
| 508 | Only accept beneficial pleasures [Democritus (attr)] |
| Full Idea: Accept no pleasure unless it is beneficial. | |
| From: Democritus (attrib) (reports [c.250 BCE], B074) | |
| A reaction: Maybe all pleasures bestow some benefit - even if they are linked to harm. I struggle to see what is wrong with a harmless and non-beneficial pleasure, and I doubt if anyone could explain it to me. |
| 520 | The great pleasures come from the contemplation of noble works [Democritus (attr)] |
| Full Idea: The great pleasures come from the contemplation of noble works. | |
| From: Democritus (attrib) (reports [c.250 BCE], B194), quoted by John Stobaeus - Anthology 3.03.46 | |
| A reaction: Only, of course, for those able to perceive the nobility. In what does the 'nobility' consist, other than in the morally acceptable pleasure? Hard to explain 'noble'. Just 'wow!'? |
| 522 | Moderation brings more pleasures, and so increases pleasure [Democritus (attr)] |
| Full Idea: Moderation multiplies pleasures, and increases pleasure. | |
| From: Democritus (attrib) (reports [c.250 BCE], B211), quoted by John Stobaeus - Anthology 3.05.27 | |
| A reaction: So moderation is a sneaky trick to avoid moderation? I presume the most intense pleasures are mostly unfamiliar, and so add novelty to the mix. Apart from eating chocolate, of course. |
| 506 | Immoderate desire is the mark of a child, not an adult [Democritus (attr)] |
| Full Idea: Immoderate desire is the mark of a child, not a man. | |
| From: Democritus (attrib) (reports [c.250 BCE], B070) | |
| A reaction: Not factually correct, since the world is full of adults who have immoderate desires (notably for money). However, there are plenty of grown ups who don't seem very adult. |
| 523 | It is as brave to master pleasure as to overcome the enemy [Democritus (attr)] |
| Full Idea: The brave man is not only he who overcomes the enemy, but he who is stronger than pleasures. Some men are masters of cities, but are enslaved by women. | |
| From: Democritus (attrib) (reports [c.250 BCE], B214), quoted by John Stobaeus - Anthology 3.07.25 | |
| A reaction: I'm not sure if 'bravery' is the relevant virtue here.Sounds like self-control or temperance. I suspect that mastering a city is quite pleasurable, if that's your thing. |
| 497 | Be virtuous from duty, not from fear [Democritus (attr)] |
| Full Idea: Refrain from crimes not through fear but through duty [deon]. | |
| From: Democritus (attrib) (reports [c.250 BCE], B041), quoted by John Stobaeus - Anthology 3.01.95 | |
| A reaction: [not sure about the translation here] |
| 518 | A bad life is just a drawn-out death [Democritus (attr)] |
| Full Idea: To live badly is not just to live badly, but to spend a long time dying. | |
| From: Democritus (attrib) (reports [c.250 BCE], B160), quoted by (who?) - where? |
| 503 | Virtue doesn't just avoid evil, but also doesn't desire it [Democritus (attr)] |
| Full Idea: Virtue consists, not in avoiding wrong-doing, but in having no wish thereto. | |
| From: Democritus (attrib) (reports [c.250 BCE], B062), quoted by John Stobaeus - Anthology 3.17.37 |
| 499 | Repentance of shameful deeds is salvation [Democritus (attr)] |
| Full Idea: Repentance for shameful deeds is salvation in life. | |
| From: Democritus (attrib) (reports [c.250 BCE], B043) |
| 524 | Virtue comes more from practice than from nature [Democritus (attr)] |
| Full Idea: More men become good through practice than by nature. | |
| From: Democritus (attrib) (reports [c.250 BCE], B242), quoted by John Stobaeus - Anthology 3.29.66 |
| 519 | One must avoid even speaking of evil deeds [Democritus (attr)] |
| Full Idea: One must avoid even speaking of evil deeds. | |
| From: Democritus (attrib) (reports [c.250 BCE], B190), quoted by John Stobaeus - Anthology 3.01.91 |
| 500 | The wrongdoer is more unfortunate than the person wronged [Democritus (attr)] |
| Full Idea: The wrongdoer is more unfortunate than the man wronged. | |
| From: Democritus (attrib) (reports [c.250 BCE], B045) |
| 1539 | The endless desire for money is a crueller slavery than poverty [Democritus (attr)] |
| Full Idea: Unless a point of satiety is reached, the desire for money is far more cruel than the utmost poverty, because the greater the desire, the greater the need | |
| From: Democritus (attrib) (reports [c.250 BCE], B219), quoted by John Stobaeus - Anthology 3.10.43 |
| 526 | Small appetite makes poverty equal to wealth [Democritus (attr)] |
| Full Idea: Small appetite makes poverty equivalent to wealth. | |
| From: Democritus (attrib) (reports [c.250 BCE], B284), quoted by John Stobaeus - Anthology 4.33.24 |
| 511 | It is better to have one intelligent friend than many unintelligent [Democritus (attr)] |
| Full Idea: The friendship of one intelligent man is better than that of all the unintelligent. | |
| From: Democritus (attrib) (reports [c.250 BCE], B098) |
| 498 | It is a great thing, when one is in adversity, to think of duty [Democritus (attr)] |
| Full Idea: It is a great thing, when one is in adversity, to think of duty. | |
| From: Democritus (attrib) (reports [c.250 BCE], B042), quoted by John Stobaeus - Anthology 4.44.68 | |
| A reaction: Something wrong with the translation here, if there is no Greek word for 'duty'. |
| 1541 | It is better to be poor in a democracy than be rich without freedom [Democritus (attr)] |
| Full Idea: Poverty in a democracy is as preferable to what is called prosperity under autocracy as freedom is to slavery. | |
| From: Democritus (attrib) (reports [c.250 BCE], B251), quoted by John Stobaeus - Anthology 3.40.42 |