16 ideas
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'. |
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. |
7746 | We don't normally think of names as having senses (e.g. we don't give definitions of them) [Searle] |
Full Idea: If Tully=Cicero is synthetic, the names must have different senses, which seems implausible, for we don't normally think of proper names as having senses in the way that predicates do (we do not, e.g., give definitions of proper names). | |
From: John Searle (Proper Names [1958], p.89) | |
A reaction: It is probably necessary to prize apart the question of whether Tully 'has' (intrinsically) a sense, from whether we think of Tully in that way. Stacks of books have appeared about this one, since Kripke. |
7747 | How can a proper name be correlated with its object if it hasn't got a sense? [Searle] |
Full Idea: It seems that a proper name could not have a reference unless it did have a sense, for how, unless the name has a sense, is it to be correlated with the object? | |
From: John Searle (Proper Names [1958], p.91) | |
A reaction: This might (just) be the most important question ever asked in modern philosophy, since it provoked Kripke into answering it, by giving a social, causal, externalist account of how names (and hence lots of language) actually work. But Searle has a point. |
7748 | 'Aristotle' means more than just 'an object that was christened "Aristotle"' [Searle] |
Full Idea: Aristotle being identical with an object that was originally christened will not suffice, for the force of "Aristotle" is greater than the force of 'identical with an object named "Aristotle"', for not just any object named "Aristotle" will do. | |
From: John Searle (Proper Names [1958], p.93) | |
A reaction: This anticipates Kripke's proposal to base reference on baptism. I remain unsure about how rigid a designation of Aristotle could be, in a possible world where his father died young, and he became an illiterate soldier who hates philosophy. |
7749 | Reference for proper names presupposes a set of uniquely referring descriptions [Searle] |
Full Idea: To use a proper name referringly is to presuppose the truth of certain uniquely referring descriptive statements. ...Names are pegs on which to hang descriptions. | |
From: John Searle (Proper Names [1958], p.94) | |
A reaction: This 'cluster' view of Searle's has become notorious, but I think one could at least try to mount a defence. The objection to Searle is that none of the descriptions are necessary, unlike just being the named object. |
7750 | Proper names are logically connected with their characteristics, in a loose way [Searle] |
Full Idea: If asked whether or not proper names are logically connected with characteristics of the object to which they refer, the answer is 'yes, in a loose sort of way'. | |
From: John Searle (Proper Names [1958], p.96) | |
A reaction: It seems to be inviting trouble to assert that a connection is both 'logical' and 'loose'. Clearly Searle has been reading too much later Wittgenstein. This is probably the weakest point in Searle's proposal, which brought a landslide of criticism. |
9762 | We should focus less on subjects of experience, and more on the experiences themselves [Parfit] |
Full Idea: It becomes more plausible, when thinking morally, to focus less upon the person, the subject of experiences, and instead to focus more upon the experiences themselves. | |
From: Derek Parfit (Reasons and Persons [1984], §116) | |
A reaction: This pinpoints how Parfit moves from a view of persons in terms of continuity of consciousness to a utilitarian morality. It brings out nicely what is wrong with utilitarianism - the reductio of a great ball of nice experiences, with no one having them. |