19125
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If we define truth, we can eliminate it [Halbach/Leigh]
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Full Idea:
If truth can be explicitly defined, it can be eliminated.
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From:
Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.3)
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A reaction:
That we could just say p corresponds to the facts, or p coheres with our accepted beliefs, or p is the aim of our enquiries, and never mention the word 'true'. Definition is a strategy for reduction or elimination.
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19127
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The T-sentences are deductively weak, and also not deductively conservative [Halbach/Leigh]
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Full Idea:
Although the theory is materially adequate, Tarski thought that the T-sentences are deductively too weak. …Also it seems that the T-sentences are not conservative, because they prove in PA that 0=0 and ¬0=0 are different, so at least two objects exist.
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From:
Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 3.2)
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A reaction:
They are weak because they can't prove completeness. This idea give two reasons for looking for a better theory of truth.
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19124
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A natural theory of truth plays the role of reflection principles, establishing arithmetic's soundness [Halbach/Leigh]
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Full Idea:
If a natural theory of truth is added to Peano Arithmetic, it is not necessary to add explicity global reflection principles to assert soundness, as the truth theory proves them. Truth theories thus prove soundess, and allows its expression.
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From:
Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.2)
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A reaction:
This seems like a big attraction of axiomatic theories of truth for students of metamathematics.
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19126
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If deflationary truth is not explanatory, truth axioms should be 'conservative', proving nothing new [Halbach/Leigh]
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Full Idea:
If truth does not have any explanatory force, as some deflationists claim, the axioms of truth should not allow us to prove any new theorems that do not involve the truth predicate. That is, a deflationary axiomatisation of truth should be 'conservative'.
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From:
Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.3)
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A reaction:
So does truth have 'explanatory force'? These guys are interested in explaining theorems of arithmetic, but I'm more interested in real life. People do daft things because they have daft beliefs. Logic should be neutral, but truth has values?
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19129
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The FS axioms use classical logical, but are not fully consistent [Halbach/Leigh]
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Full Idea:
It is a virtue of the Friedman-Sheard axiomatisation that it is thoroughly classical in its logic. Its drawback is that it is ω-inconsistent. That is, it proves &exists;x¬φ(x), but proves also φ(0), φ(1), φ(2), …
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From:
Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 4.3)
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A reaction:
It seems the theory is complete (and presumably sound), yet not fully consistent. FS also proves the finite levels of Tarski's hierarchy, but not the transfinite levels.
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19130
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KF is formulated in classical logic, but describes non-classical truth, which allows truth-value gluts [Halbach/Leigh]
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Full Idea:
KF is formulated in classical logic, but describes a non-classical notion of truth. It allow truth-value gluts, making some sentences (such as the Liar) both true and not-true. Some authors add an axiom ruling out such gluts.
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From:
Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 4.4)
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A reaction:
[summary, which I hope is correct! Stanford is not wholly clear]
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19121
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We can reduce properties to true formulas [Halbach/Leigh]
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Full Idea:
One might say that 'x is a poor philosopher' is true of Tom instead of saying that Tom has the property of being a poor philosopher. We quantify over formulas instead of over definable properties, and thus reduce properties to truth.
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From:
Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.1)
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A reaction:
[compressed] This stuff is difficult (because the axioms are complex and hard to compare), but I am excited (yes!) about this idea. Their point is that you need a truth predicate within the object language for this, which disquotational truth forbids.
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14753
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The 'dominant' of two coinciding sortals is the one that entails the widest range of properties [Burke,M, by Sider]
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Full Idea:
Burke claims that the 'dominant' sortal is the one whose satisfaction entails possession of the widest range of properties. For example, the statue (unlike the lump of clay) also possesses aesthetic properties, and hence is dominant.
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From:
report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Theodore Sider - Four Dimensionalism 5.4
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A reaction:
[there are three papers by Burke on this; see all the quotations from Burke] Presumably one sortal could entail a single very important property, and the other sortal entail a huge range of trivial properties. What does being a 'thing' entail?
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16072
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'The rock' either refers to an object, or to a collection of parts, or to some stuff [Burke,M, by Wasserman]
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Full Idea:
Burke distinguishes three different readings of 'the rock'. It can be a singular description denoting an object, or a plural description denoting all the little pieces of rock, or a mass description the relevant rocky stuff.
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From:
report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Ryan Wasserman - Material Constitution 5
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A reaction:
Idea 16068 is an objection to the second reading. Only the first reading seems plausible, so we must just get over all the difficulties philosophers have unearthed about knowing exactly what an 'object' is. I offer you essentialism. Rocks have unity.
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16234
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Burke says when two object coincide, one of them is destroyed in the process [Burke,M, by Hawley]
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Full Idea:
Michael Burke argues that a sweater is identical with the thread that consitutes it, that both were created at the moment when they began to coincide, and that the original thread was destroyed in the process.
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From:
report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Katherine Hawley - How Things Persist 5.3
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A reaction:
[Burke's ideas are spread over three articles] It is the thread which is destroyed, because the sweater is the 'dominant sortal' (which strikes me as a particularlyd desperate concept).
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14750
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Two entities can coincide as one, but only one of them (the dominant sortal) fixes persistence conditions [Burke,M, by Sider]
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Full Idea:
Michael Burke has given an account that avoids distinguishing coinciding entities. ...The statue/lump satisfies both 'lump' and 'statue', but only the latter determines that object's persistence conditions, and so is that object's 'dominant sortal'.
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From:
report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Theodore Sider - Four Dimensionalism 5.4
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A reaction:
Presumably a lump on its own can have its own persistance conditions (as a 'lump'), but those would presumably be lost if you shaped it into a statue. Burke concedes that. Can of worms. Using a book as a doorstop...
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