27 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. |
| 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. |
| 12056 | An ancestral relation is either direct or transitively indirect [Wiggins] |
| Full Idea: x bears to y the 'ancestral' of the relation R just if either x bears R to y, or x bears R to some w that bears R to y, or x bears R to some w that bears R to some z that bears R to y, or..... | |
| From: David Wiggins (Substance [1995], 4.10.1) | |
| A reaction: A concept invented by Frege (1879). |
| 12050 | Substances contain a source of change or principle of activity [Wiggins] |
| Full Idea: Substances are things that have a source of change or principle of activity within them. | |
| From: David Wiggins (Substance [1995], 4.4.1) | |
| A reaction: A vey significant concession. I think we can talk of 'essences' and 'powers', and drop talk of 'substances'. 'Powers' is a much better word, because it immediately pushes the active ingredient to the forefront. |
| 12052 | We never single out just 'this', but always 'this something-or-other' [Wiggins] |
| Full Idea: What is singled out is never a bare this or that, but this or that something or other. | |
| From: David Wiggins (Substance [1995], 4.5.1) | |
| A reaction: I like, in ontological speculation, to contemplate the problem of the baffling archaeological find. 'This thing I have dug up - what the hell IS it?'. Wiggins is contemptuous of the term 'thisness', and the idea of bare particulars. |
| 12055 | Sortal predications are answers to the question 'what is x?' [Wiggins] |
| Full Idea: Predications which answer the question 'what is x?' are often called 'sortal predications' in present-day philosophy. | |
| From: David Wiggins (Substance [1995], 4.10.1) | |
| A reaction: The word 'sortal' comes from Locke. Wiggins is the guru of 'sortal essentialism'. I just can't believe that in answer to the question 'what really is David Wiggins?' that he would be happy with a sequence of categorisations. |
| 12059 | A river may change constantly, but not in respect of being a river [Wiggins] |
| Full Idea: To say that the river is changing constantly in every respect is not to say that it is changing in respect of being a river. | |
| From: David Wiggins (Substance [1995], 4.11.2) | |
| A reaction: Can't a river become a lake, or a mere stream? Wiggins's proposal does not help with the problem of a river which sometimes dries up (as my local river sometimes does). At what point do we decide it is no longer a river? |
| 12063 | Sortal classification becomes science, with cross reference clarifying individuals [Wiggins] |
| Full Idea: The sense of the sortal term under which we pick out an individual expands into the scientific account of things of that kind, where the account clarifies what is at issue in questions of sameness and difference of specimens of that kind. | |
| From: David Wiggins (Substance [1995], 4.13.1) | |
| A reaction: This is how the sortal approach is supposed to deal with individuals. So the placid tiger reveals much by falling under 'tiger', and a crucial extra bit by falling under 'placid'. See Idea 12053 for problems with this proposal. |
| 12051 | If the kinds are divided realistically, they fall into substances [Wiggins] |
| Full Idea: Substance are what the world is articulated into when the segments of kinds corresponds to the real divisions in reality. | |
| From: David Wiggins (Substance [1995], 4.5.1) | |
| A reaction: This is very helpful in clarifying Wiggins's very obscurely expressed views. He appears to be saying that if we divide the sheep from the goats correctly, we reveal sheep-substance and goat-substance (one substance per species). Crazy! |
| 12053 | 'Human being' is a better answer to 'what is it?' than 'poet', as the latter comes in degrees [Wiggins] |
| Full Idea: One person can be more or less of a poet than another, so 'poet' is not a conclusory answer to the question 'What is it that is singled out here?' 'Poet' rides on the back of the answer 'human being'. | |
| From: David Wiggins (Substance [1995], 4.5.1) | |
| A reaction: So apparently one must assign a natural kind, and not just a class. Wiggins lacks science fiction imagination. In the genetic salad of the far future, being a poet may be more definitive than being a human being. See Idea 12063. |
| 12054 | Secondary substances correctly divide primary substances by activity-principles and relations [Wiggins] |
| Full Idea: A system of secondary substances with a claim to separate reality into its genuine primary substances must arise from an understanding of a set of principles of activity on the basis of which identities can be glossed in terms of determinate relations. | |
| From: David Wiggins (Substance [1995], 4.5.1) | |
| A reaction: I translate this as saying that individual essences are categorised according to principles which explain behaviour and relations. I'm increasingly bewildered by the 'secondary substances' Wiggins got from 'Categories', and loves so much. |
| 12047 | We refer to persisting substances, in perception and in thought, and they aid understanding [Wiggins] |
| Full Idea: A substance is a persisting and somehow basic object of reference that is there to be discovered in perception and thought, an object whose claim to be recognized as a real entity is a claim on our aspirations to understand the world. | |
| From: David Wiggins (Substance [1995], 4.1) | |
| A reaction: A lot of components are assigned by Wiggins to the concept, and the tricky job, inititiated by Aristotle, is to fit all the pieces together nicely. Personally I am wondering if the acceptance of 'essences' implies dropping 'substances'. |
| 12057 | Matter underlies things, composes things, and brings them to be [Wiggins] |
| Full Idea: Matter ex hypothesi is what ultimately underlies (to huperkeimenon) a thing; it is that from which something comes to be and which remains as a non-coincidental component in the thing's make-up. | |
| From: David Wiggins (Substance [1995], 192a30) | |
| A reaction: This is an interesting prelude to the much more comprehensive discussion of matter in Metaphysics, where he crucially adds the notion of 'form', and gives it priority over the underlying matter. |
| 335 | Do the gods also hold different opinions about what is right and honourable? [Plato] |
| Full Idea: Do the gods too hold different opinions about what is right, and similarly about what is honourable and dishonourable, good and bad? | |
| From: Plato (Euthyphro [c.398 BCE], 07e) |
| 12064 | The category of substance is more important for epistemology than for ontology [Wiggins] |
| Full Idea: For us the importance of the category of substance, if it has any importance, is not so much ontological as relative to our epistemological circumstances and the conditions under which we have to undertake inquiry. | |
| From: David Wiggins (Substance [1995], 4.13.2) | |
| A reaction: This seems to be a rather significant concession. Wiggins has revived the notion of substance in recent times, but he is not quite adding it to the furniture of the world. Personally I increasingly think we can dump it, in ontology and epistemology. |
| 12049 | Naming the secondary substance provides a mass of general information [Wiggins] |
| Full Idea: Answering 'what is it?' with the secondary substance identifies an object with a class of continuants which survive certain changes, come into being in certain ways, are qualified in certain ways, behave in certain ways, and cease to be in certain ways. | |
| From: David Wiggins (Substance [1995], 4.3.3) | |
| A reaction: Thus the priority of this sort of answer is that a huge range of explanations immediately flow from it. I take the explanation to be prior, and the primary substance to be prior, since secondary substance is inductively derived from it. |
| 12065 | Seeing a group of soldiers as an army is irresistible, in ontology and explanation [Wiggins] |
| Full Idea: It seems mandatory to an observer of soldiers to give 'the final touch of unity' to their aggregate entity (the army). ...Similar claims arise with the ontological and explanatory claims of other corporate entities. | |
| From: David Wiggins (Substance [1995], 4.13.3) | |
| A reaction: Wiggins must say (following Leibniz Essays II.xxiv,1) that we add the unity, but I take the view that an army has powers, and hence offers explanations, which are lacking in a merely group of disparate soldiers. So an army has an essence and identity. |
| 336 | Is what is pious loved by the gods because it is pious, or is it pious because they love it? (the 'Euthyphro Question') [Plato] |
| Full Idea: Is what is pious loved by the gods because it is pious, or is it pious because they love it? | |
| From: Plato (Euthyphro [c.398 BCE], 10a) | |
| A reaction: The famous Euthyphro Question, the key question about the supposed religious basis of morality. The answer of Socrates is Idea 337. |
| 337 | It seems that the gods love things because they are pious, rather than making them pious by loving them [Plato] |
| Full Idea: So things are loved by the gods because they are pious, and not pious because they are loved? It seems so. | |
| From: Plato (Euthyphro [c.398 BCE], 10e) | |
| A reaction: Socrates' answer to the Euthyphro Question (see Idea 336). The form of piety precedes the gods. |