Combining Texts

All the ideas for 'On the Question of Absolute Undecidability', 'Identity and Necessity' and 'Things and Their Parts'

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22 ideas

4. Formal Logic / F. Set Theory ST / 1. Set Theory
17884 Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner]
     Full Idea: There are many coherent stopping points in the hierarchy of increasingly strong mathematical systems, starting with strict finitism, and moving up through predicativism to the higher reaches of set theory.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], Intro)
17893 'Reflection principles' say the whole truth about sets can't be captured [Koellner]
     Full Idea: Roughly speaking, 'reflection principles' assert that anything true in V [the set hierarchy] falls short of characterising V in that it is true within some earlier level.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 2.1)
4. Formal Logic / G. Formal Mereology / 1. Mereology
13331 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 / F. Referring in Logic / 1. Naming / b. Names as descriptive
9175 We may fix the reference of 'Cicero' by a description, but thereafter the name is rigid [Kripke]
     Full Idea: We may fix the reference of 'Cicero' by use of some descriptive phrase, such as 'author of these works'. But once we have this reference fixed, we then use the name 'Cicero' rigidly to designate the man who in fact we have identified by his authorship.
     From: Saul A. Kripke (Identity and Necessity [1971], p.183)
     A reaction: Even supposedly rigid names can shift reference, as Evans's example of 'Madagascar' shows (Idea 9041). Reference is a much more social activity than Kripke is willing to admit. There is a 'tradition' of reference (Dummett) for the name 'Cicero'.
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
9171 The function of names is simply to refer [Kripke]
     Full Idea: The function of names is simply to refer.
     From: Saul A. Kripke (Identity and Necessity [1971], p.167)
     A reaction: This is Kripke reverting to the John Stuart Mill view of names. If I say "you are a right Casanova" I don't simply refer to Casanova. In notorious examples like 'Homer' reference is fine, but the object of reference is a bit elusive.
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
17894 We have no argument to show a statement is absolutely undecidable [Koellner]
     Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
17890 There are at least eleven types of large cardinal, of increasing logical strength [Koellner]
     Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable).
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
     A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
17887 PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner]
     Full Idea: To the extent that we are justified in accepting Peano Arithmetic we are justified in accepting its consistency, and so we know how to expand the axiom system so as to overcome the limitation [of Gödel's Second Theorem].
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.1)
     A reaction: Each expansion brings a limitation, but then you can expand again.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
17891 Arithmetical undecidability is always settled at the next stage up [Koellner]
     Full Idea: The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
9. Objects / B. Unity of Objects / 1. Unifying an Object / c. Unity as conceptual
13332 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
13333 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
13326 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.
13327 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
13329 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.
13330 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
13328 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).
10. Modality / D. Knowledge of Modality / 3. A Posteriori Necessary
9174 It is necessary that this table is not made of ice, but we don't know it a priori [Kripke]
     Full Idea: Although the statement that this table (if it exists at all) was not made of ice, is necessary, it certainly is not something that we know a priori.
     From: Saul A. Kripke (Identity and Necessity [1971], p.180)
     A reaction: One of the key thoughts in modern philosophy. Kit Fine warns against treating it as a new and exciting toy, but it is a new and exciting toy. Scientific essentialism, which I so want to be true, is built on this proposal.
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
9172 A 'rigid designator' designates the same object in all possible worlds [Kripke]
     Full Idea: By 'rigid designator' I mean a term that designates the same object in all possible worlds.
     From: Saul A. Kripke (Identity and Necessity [1971])
     A reaction: I am persistently troubled by the case of objects which are slightly different in another possible world. Does 'Aristotle' refer to him as young or old? Might the very same man have had a mole on his cheek?
9173 We cannot say that Nixon might have been a different man from the one he actually was [Kripke]
     Full Idea: It seems that we cannot say "Nixon might have been a different man from the man he in fact was", unless we mean it metaphorically. He might have been a different sort of person.
     From: Saul A. Kripke (Identity and Necessity [1971], p.176)
     A reaction: The problem is that being a 'different sort of person' could become more and more drastic, till Nixon is unrecognisable. I don't see how I can stipulate that a small and dim mouse is Richard Nixon, even in a possible world with magicians.
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
9176 Modal statements about this table never refer to counterparts; that confuses epistemology and metaphysics [Kripke]
     Full Idea: Statements about the modal properties of this table never refer to counterparts. However, if someone confuses the epistemological problems and the metaphysical problems he will be well on the way to the counterpart theory of Lewis.
     From: Saul A. Kripke (Identity and Necessity [1971], p.184 n16)
     A reaction: I can't make out what we should say about a possible object which is very nearly this table. Kripke needs the table to have a clear and unwavering essence, but tables are not that sort of thing. How would Kripke define 'physical object'?
17. Mind and Body / A. Mind-Body Dualism / 7. Zombies
9177 Identity theorists must deny that pains can be imagined without brain states [Kripke]
     Full Idea: The identity theorist has to hold that we are under some illusion in thinking that we can imagine that there could have been pains without brain states.
     From: Saul A. Kripke (Identity and Necessity [1971], p.190)
     A reaction: The origin of Robert Kirk's idea that there might be zombies. Kripke is wrong. Of course Kripke and his friends can imagine disembodied pains; the question is whether being able to imagine them makes them possible, which it doesn't.
17. Mind and Body / E. Mind as Physical / 7. Anti-Physicalism / e. Modal argument
9178 Pain, unlike heat, is picked out by an essential property [Kripke]
     Full Idea: 'Heat' is a rigid designator, which is picked out by the contingent property of being felt in a certain way; pain, on the other hand, is picked out by an essential (indeed necessary and sufficient) property.
     From: Saul A. Kripke (Identity and Necessity [1971], p.190 n19)
     A reaction: Hm. I could pick out your pain by your contingent whimpering behaviour. I can spot my own potential pain by a combination of bodily damage and pain killing tablets. I suspect him of the same blunder as Descartes on this one.