Combining Texts

All the ideas for 'On the Question of Absolute Undecidability', 'Explanations in reply to Mr Bradley' and 'Deflating Existential Consequence'

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19 ideas

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
Philosophers should be more inductive, and test results by their conclusions, not their self-evidence [Russell]
     Full Idea: The progress of philosophy seems to demand that, like science, it should learn to practise induction, to test its premisses by the conclusions to which they lead, and not merely by their apparent self-evidence.
     From: Bertrand Russell (Explanations in reply to Mr Bradley [1899], nr end)
     A reaction: [from Twitter] Love this. It is 'one person's modus ponens is another person's modus tollens'. I think all philosophical conclusions, without exception, should be reached by evaluating the final result fully, and not just following a line of argument.
3. Truth / B. Truthmakers / 12. Rejecting Truthmakers
'Mickey Mouse is a fictional mouse' is true without a truthmaker [Azzouni]
     Full Idea: 'Mickey Mouse is a fictional mouse' can be taken as true without have any truthmaker.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.3)
     A reaction: There might be an equivocation over 'true' here. 'What, really really true that he IS a fictional mouse?'
3. Truth / H. Deflationary Truth / 1. Redundant Truth
Truth is dispensable, by replacing truth claims with the sentence itself [Azzouni]
     Full Idea: No truth predicate is ever indispensable, because Tarski biconditionals, the equivalences between sentences and explicit truth ascriptions to those sentences, allow us to replace explicit truth ascriptions with the sentences themselves.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.1)
     A reaction: Holding a sentence to be true isn't the same as saying that it is true, and it isn't the same as saying the sentence, because one might say it in an ironic tone of voice.
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
Truth lets us assent to sentences we can't explicitly exhibit [Azzouni]
     Full Idea: My take on truth is a fairly deflationary one: The role of the truth predicate is to enable us to assent to sentences we can't explicitly exhibit.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Intro)
     A reaction: Clearly this is a role for truth, as in 'I forget what he said, but I know it was true', but it isn't remotely what most people understand by true. We use 'true' about totally explicit sentences all the time.
4. Formal Logic / F. Set Theory ST / 1. Set Theory
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)
'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)
5. Theory of Logic / F. Referring in Logic / 1. Naming / e. Empty names
Names function the same way, even if there is no object [Azzouni]
     Full Idea: Names function the same way (semantically and grammatically) regardless of whether or not there's an object that they refer to.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.3 n55)
     A reaction: I take this to be a fairly clear rebuttal of the 'Fido'-Fido view of names (that the meaning of the name IS the dog), which never seems to quite go away. A name is a peg on which description may be hung, seems a good slogan to me.
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
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
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
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
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)
7. Existence / A. Nature of Existence / 6. Criterion for Existence
That all existents have causal powers is unknowable; the claim is simply an epistemic one [Azzouni]
     Full Idea: If the argument isn't that, metaphysically speaking, anything that exists must have causal powers - how on earth would we show that? - rather, the claim is an epistemic one. Any thing we're in a position to know about we must causally interact with.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.4)
     A reaction: A very good point. I am attracted to causal power as a criterion for existence, but Azzouni's distinction is vital. Maybe there is just no point in even talking about things which exist but have no causal powers.
7. Existence / D. Theories of Reality / 7. Fictionalism
If fictional objects really don't exist, then they aren't abstract objects [Azzouni]
     Full Idea: It's robustly part of common sense that fictional objects don't exist in any sense at all, and this means they aren't abstracta either.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.3)
     A reaction: Nice. It is so easy to have some philosopher dilute and equivocate over the word 'object' until you find yourself committed to all sorts of daft things as somehow having objectual existence. We can discuss things which don't exist in any way at all.
7. Existence / D. Theories of Reality / 11. Ontological Commitment / a. Ontological commitment
Modern metaphysics often derives ontology from the logical forms of sentences [Azzouni]
     Full Idea: It is widespread in contemporary metaphysics to extract commitments to various types of object on the basis of the logical form of certain sentences.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.7)
     A reaction: I'm with Azzouni in thinking that this procedure is a very bad idea. I'm increasingly inclined towards the wild view that people are only ontologically committed to things if they explicitly say that they are so committed.
7. Existence / D. Theories of Reality / 11. Ontological Commitment / b. Commitment of quantifiers
If objectual quantifiers ontologically commit, so does the metalanguage for its semantics [Azzouni]
     Full Idea: The argument that objectual quantifiers are ontologically committing has the crucial and unnoticed presupposition that the language in which the semantics for the objectual quantifiers is couched (the 'metalanguage') also has quantifiers with commitment.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.3)
     A reaction: That is, presumably we find ourselves ontologically committed to the existence of quantifiers, and are also looking at an infinite regress. See Idea 12439.
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
In the vernacular there is no unequivocal ontological commitment [Azzouni]
     Full Idea: There are no linguistic devices, no idioms (not 'there is', not 'exists') that unequivocally indicate ontological commitment in the vernacular.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Intro)
     A reaction: This seems right, since people talk in such ways about soap opera, while understanding the ontological situation perfectly well. Presumably Quine is seeking higher standards than the vernacular, if we are doing science.
We only get ontology from semantics if we have already smuggled it in [Azzouni]
     Full Idea: A slogan: One can't read ontological commitments from semantic conditions unless one has already smuggled into those semantic conditions the ontology one would like to read off.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.3)
     A reaction: The arguments supporting this are subtle, but it's good enough for me, as I never thought anyone was ontologically committed just because they used the vagueries of language to try to say what's going on around here.
9. Objects / A. Existence of Objects / 4. Impossible objects
Things that don't exist don't have any properties [Azzouni]
     Full Idea: Things that don't exist don't have any properties.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.4)
     A reaction: Sounds reasonable! I totally agree, but that is because my notion of properties is sparse and naturalistic. If you identify properties with predicates (which some weird people seem to), then non-existents can have properties like 'absence' or 'nullity'.
27. Natural Reality / F. Chemistry / 3. Periodic Table
The periodic table not only defines the elements, but also excludes other possible elements [Azzouni]
     Full Idea: The periodic table not only governs what elements there can be, with their properties, but also explicitly excludes others sorts of elements, because the elements are individuated by the number of discrete protons in their nuclei.
     From: Jody Azzouni (Deflating Existential Consequence [2004], Ch.7)
     A reaction: It has to be central to the thesis of scientific essentialism that the possibilities in nature are far more restricted than is normally thought, and this observation illustrates the view nicely. He makes a similar point about subatomic particles.