23 ideas
| 6396 | A sentence is held true because of a combination of meaning and belief [Davidson] |
| Full Idea: A sentence is held true because of two factors: what the holder takes the sentence to mean, and what he believes. | |
| From: Donald Davidson (Thought and Talk [1975], p.20) | |
| A reaction: A key question is whether a belief (e.g. an imagistic one, or one held by an animal) could be true, even though no sentence is involved. Linguistic philosophers tend to avoid this question, or assume the answer is 'no'. |
| 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. |
| 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) |
| 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. |
| 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'. |
| 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) |
| 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. |
| 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. |
| 8568 | A property is merely a constituent of laws of nature; temperature is just part of thermodynamics [Mellor] |
| Full Idea: Being a constituent of probabilistic laws of nature is all there is to being a property. There is no more to temperature than the thermodynamics and other laws they occur in. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: How could thermodynamics be worked out without a prior concept of temperature? I think it is at least plausible to deny that there are any 'laws' of nature. But even Quine can't deny that some things are too hot to touch. |
| 8564 | There is obviously a possible predicate for every property [Mellor] |
| Full Idea: To every property there obviously corresponds a possible predicate applying to all and only those particulars with that property. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Intro') | |
| A reaction: This doesn't strike me as at all obvious. If nature dictates the properties, there may be vastly more than any human language could cope with. It is daft to say that a property can only exist if humanity can come up with a predicate for it. |
| 8566 | We need universals for causation and laws of nature; the latter give them their identity [Mellor] |
| Full Idea: I take the main reason for believing in contingent universals to be the roles they play in causation and in laws of nature, and those laws are what I take to give those universals their identity. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: He agrees with Armstrong. Sounds a bit circular - laws are built on universals, and universals are identified by laws. It resembles a functionalist account of mental events. I think it is wrong. A different account of laws will be needed... |
| 8565 | If properties were just the meanings of predicates, they couldn't give predicates their meaning [Mellor] |
| Full Idea: One reason for denying that properties just are the meanings of our predicates is that, if they were, they could not give our predicates their meanings. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: Neither way round sounds quite right to me. Predicate nominalism is wrong, but what is meant by a property 'giving' a predicate its meaning? It doesn't seem to allow room for error in our attempts to name the properties. |
| 11145 | Having a belief involves the possibility of being mistaken [Davidson] |
| Full Idea: Someone cannot have a belief unless he understands the possibility of being mistaken. | |
| From: Donald Davidson (Thought and Talk [1975], p.170) | |
| A reaction: If you pretend to throw a ball for a dog, but don't release it, the dog experiences being mistaken very dramatically. |
| 6397 | The concept of belief can only derive from relationship to a speech community [Davidson] |
| Full Idea: We have the idea of belief from its role in the interpretation of language; as a private attitude it is not intelligible except in relation to public language. So a creature must be a member of a speech community to have the concept of belief. | |
| From: Donald Davidson (Thought and Talk [1975], p.22) | |
| A reaction: This shows how Wittgenstein's Private Language Argument (e.g. Idea 4152) hovers behind Davidson's philosophy. The idea is quite persuasive. A solitary creature just follows its mental states. The question of whether it believes them is a meta-thought. |
| 6392 | Thought depends on speech [Davidson] |
| Full Idea: The thesis I want to refine and then argue for is that thought depends on speech. | |
| From: Donald Davidson (Thought and Talk [1975], p.8) | |
| A reaction: This has the instant and rather implausible implication that animals don't think. He is not, of course, saying that all thought is speech, which would leave out thinking in images. You can't do much proper thought without concepts and propositions. |
| 6393 | A creature doesn't think unless it interprets another's speech [Davidson] |
| Full Idea: A creature cannot have a thought unless it is an interpreter of the speech of another. | |
| From: Donald Davidson (Thought and Talk [1975], p.9) | |
| A reaction: His use of the word 'creature' shows that he is perfectly aware of the issue of whether animals think, and he is, presumably, denying it. At first glance this sounds silly, but maybe animals don't really 'think', in our sense of the word. |
| 11144 | Concepts are only possible in a language community [Davidson] |
| Full Idea: A private attitude is not intelligible except as an adjustment to the public norms provided by language. It follows that a creature must be a member of speech community if it is to have the concept of belief. | |
| From: Donald Davidson (Thought and Talk [1975], p.170) | |
| A reaction: This obviously draws on Wittgenstein's private language argument, and strikes me as blatantly wrong, because I take higher animals to have concepts without language. Pure vision gives rise to concepts. I don't even think they are necessarily conscious. |
| 6395 | An understood sentence can be used for almost anything; it isn't language if it has only one use [Davidson] |
| Full Idea: Once a sentence is understood, an utterance of it may be used to serve almost any extra-linguistic purpose; an instrument that could be put to only one use would lack autonomy of meaning, which means it should not be counted as language. | |
| From: Donald Davidson (Thought and Talk [1975], p.17) | |
| A reaction: I find this point very appealing, in opposition to the Wittgenstein view of meaning as use. Passwords seem to me a striking case of the separation of meaning and use. I like the phrase 'autonomy of meaning'. Random sticks can form a word. |
| 6394 | The pattern of sentences held true gives sentences their meaning [Davidson] |
| Full Idea: Although most utterances are not concerned with truth, it is the pattern of sentences held true that gives sentences their meaning. | |
| From: Donald Davidson (Thought and Talk [1975], p.14) | |
| A reaction: Davidson's distinctive version of meaning holism, as opposed to Quine's rather behaviouristic version. I agree that we relate to people through the pattern of sentences they hold true, but I am unconvinced that this 'gives sentences their meaning'. |
| 8567 | Singular causation requires causes to raise the physical probability of their effects [Mellor] |
| Full Idea: Singular causation entails physical probabilities or chances. ...Causal laws require causes to raise their effects' chances, as when fires have a greater chance of occurring when explosions do. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: It seems fairly obvious that a probability can be increased without actually causing something. Just after a harmless explosion is a good moment for arsonists, especially if Mellor will be the investigating officer. |