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All the ideas for 'Axiomatic Theories of Truth (2005 ver)', 'fragments/reports' and 'Things and Their Parts'

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20 ideas

3. Truth / A. Truth Problems / 2. Defining Truth
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.
3. Truth / F. Semantic Truth / 1. Tarski's Truth / c. Meta-language for truth
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.
3. Truth / G. Axiomatic Truth / 1. Axiomatic Truth
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]
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.
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)
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.
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
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'.
4. Formal Logic / F. Set Theory ST / 1. Set Theory
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)
4. Formal Logic / G. Formal Mereology / 1. Mereology
Part and whole contribute asymmetrically to one another, so must differ [Fine,K]
     Full Idea: The whole identity of a part is relevant to whether it is a part, but the identity of the whole makes a part a part. The whole part belongs to the whole as a part. The standard account in terms of time-slices fails to respect this part/whole asymmetry.
     From: Kit Fine (Things and Their Parts [1999], §2)
     A reaction: Hard to follow, but I think the asymmetry is that the wholeness of the part contributes to the wholeness of the whole, while the wholeness of the whole contributes to the parthood of the part. Wholeness does different jobs in different directions. OK?
5. Theory of Logic / C. Ontology of Logic / 1. Ontology of Logic
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.
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
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.
9. Objects / B. Unity of Objects / 1. Unifying an Object / c. Unity as conceptual
Hierarchical set membership models objects better than the subset or aggregate relations do [Fine,K]
     Full Idea: It is the hierarchical conception of sets and their members, rather than the linear conception of set and subset or of aggregate and component, that provides us with the better model for the structure of part-whole in its application to material things.
     From: Kit Fine (Things and Their Parts [1999], §5)
     A reaction: His idea is to give some sort of internal structure. He says of {a,b,c,d} that we can create subsets {a,b} and {c,d} from that. But {{a,b},{c,d}} has given member sets, and he is looking for 'natural' divisions between the members.
9. Objects / C. Structure of Objects / 3. Matter of an Object
The matter is a relatively unstructured version of the object, like a set without membership structure [Fine,K]
     Full Idea: The wood is, as it were, a relatively unstructured version of the tree, just as the set {a,b,c,d} is an unstructured counterpart of the set {{a,b},{c,d}}.
     From: Kit Fine (Things and Their Parts [1999], §5)
     A reaction: He is trying to give a modern logicians' account of the Aristotelian concept of 'form' (as applied to matter). It is part of the modern project that objects must be connected to the formalism of mereology or set theory. If it works, are we thereby wiser?
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
A 'temporary' part is a part at one time, but may not be at another, like a carburetor [Fine,K]
     Full Idea: First, a thing can be a part in a way that is relative to a time, for example, that a newly installed carburettor is now part of my car, whereas earlier it was not. (This will be called a 'temporary' part).
     From: Kit Fine (Things and Their Parts [1999], Intro)
     A reaction: [Cf Idea 13327 for the 'second' concept of part] I'm immediately uneasy. Being a part seems to be a univocal concept. He seems to be distinguishing parts which are necessary for identity from those which aren't. Fine likes to define by example.
A 'timeless' part just is a part, not a part at some time; some atoms are timeless parts of a water molecule [Fine,K]
     Full Idea: Second, an object can be a part of another in a way that is not relative to time ('timeless'). It is not appropriate to ask when it is a part. Thus pants and jacket are parts of the suit, atoms of a water molecule, and two pints part of a quart of milk.
     From: Kit Fine (Things and Their Parts [1999], Intro)
     A reaction: [cf Idea 13326 for the other concept of 'part'] Again I am uneasy that 'part' could have two meanings. A Life Member is a member in the same way that a normal paid up member is a member.
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
An 'aggregative' sum is spread in time, and exists whenever a component exists [Fine,K]
     Full Idea: In the 'aggregative' understanding of a sum, it is spread out in time, so that exists whenever any of its components exists (just as it is located at any time wherever any of its components are located).
     From: Kit Fine (Things and Their Parts [1999], §1)
     A reaction: This works particularly well for something like an ancient forest, which steadily changes its trees. On that view, though, the ship which has had all of its planks replaced will be the identical single sum of planks all the way through. Fine agrees.
An 'compound' sum is not spread in time, and only exists when all the components exists [Fine,K]
     Full Idea: In the 'compound' notion of sum, the mereological sum is spread out only in space, not also in time. For it to exist at a time, all of its components must exist at the time.
     From: Kit Fine (Things and Their Parts [1999], §1)
     A reaction: It is hard to think of anything to which this applies, apart from for a classical mereologist. Named parts perhaps, like Tom, Dick and Harry. Most things preserve sum identity despite replacement of parts by identical components.
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
Two sorts of whole have 'rigid embodiment' (timeless parts) or 'variable embodiment' (temporary parts) [Fine,K]
     Full Idea: I develop a version of hylomorphism, in which the theory of 'rigid embodiment' provides an account of the timeless relation of part, and the theory of 'variable embodiment' is an account of the temporary relation. We must accept two new kinds of whole.
     From: Kit Fine (Things and Their Parts [1999], Intro)
     A reaction: [see Idea 13326 and Idea 13327 for the two concepts of 'part'] This is easier to take than the two meanings for 'part'. Since Aristotle, everyone has worried about true wholes (atoms, persons?) and looser wholes (houses).
9. Objects / E. Objects over Time / 8. Continuity of Rivers
Cratylus said you couldn't even step into the same river once [Cratylus, by Aristotle]
     Full Idea: Cratylus was appalled that Heraclitus said you could not step twice into the same river, because it was already going too far to admit stepping into the same river once.
     From: report of Cratylus (fragments/reports [c.425 BCE]) by Aristotle - Metaphysics 1010a
     A reaction: Compare Idea 427.
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Cratylus decided speech was hopeless, and his only expression was the movement of a finger [Cratylus, by Aristotle]
     Full Idea: Cratylus thought speech of any kind was radically inappropriate and that expression should be restricted exclusively to the movement of the finger.
     From: report of Cratylus (fragments/reports [c.425 BCE]) by Aristotle - Metaphysics 1010a