Combining Texts

All the ideas for 'On the Question of Absolute Undecidability', 'On Duties ('De Officiis')' and 'Why Propositions Aren't Truth-Supporting Circumstance'

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11 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
Cicero sees wisdom in terms of knowledge, but earlier Stoics saw it as moral [Cicero, by Long]
     Full Idea: Cicero (drawing on Panaetius) treats wisdom as if its province were primarily a disinterested pursuit of knowledge. But earlier Stoics gave purely moral definitions of wisdom.
     From: report of M. Tullius Cicero (On Duties ('De Officiis') [c.44 BCE], 1.11-20) by A.A. Long - Hellenistic Philosophy 5
     A reaction: I would have thought that after long discussion most ancient (and even modern) philosophers would conclude that it is both. The 'intellectualism' of Socrates hovers in the background, implying that healthy knowledge produces virtue.
1. Philosophy / A. Wisdom / 2. Wise People
Unfortunately we choose a way of life before we are old enough to think clearly [Cicero]
     Full Idea: At the beginning of adolescence when our deliberative capacities are weak we decide on the way of life that we find attractive. So one gets entangled in a definite manner and pattern of life before one is able to judge which one is best.
     From: M. Tullius Cicero (On Duties ('De Officiis') [c.44 BCE], 1.117)
     A reaction: Hence it is important to have lots of means for bailing out of education courses, jobs, and even marriage. At least university postpones the key life choices till the early twenties.
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 / 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)
19. Language / C. Assigning Meanings / 2. Semantics
Semantics as theory of meaning and semantics as truth-based logical consequence are very different [Soames]
     Full Idea: There are two senses of 'semantic' - as theory of meaning or as truth-based theory of logical consequence, and they are very different.
     From: Scott Soames (Why Propositions Aren't Truth-Supporting Circumstance [2008], p.78)
     A reaction: This subtle point is significant in considering the role of logic in philosophy. The logicians' semantics (based on logical consequence) is in danger of ousting the broader and more elusive notion of meaning in natural language.
19. Language / C. Assigning Meanings / 6. Truth-Conditions Semantics
Semantic content is a proposition made of sentence constituents (not some set of circumstances) [Soames]
     Full Idea: The semantic content of a sentence is not the set of circumstances supporting its truth. It is rather the semantic content of a structured proposition the constituents of which are the semantic contents of the constituents of the sentence.
     From: Scott Soames (Why Propositions Aren't Truth-Supporting Circumstance [2008], p.74)
     A reaction: I'm not sure I get this, but while I like the truth-conditions view, I am suspicious of any proposal that the semantic content of something is some actual physical ingredients of the world. Meanings aren't sticks and stones.
23. Ethics / D. Deontological Ethics / 3. Universalisability
The essence of propriety is consistency [Cicero]
     Full Idea: The whole essence of propriety is quite certainly consistency.
     From: M. Tullius Cicero (On Duties ('De Officiis') [c.44 BCE], 1.110)
     A reaction: This seems to me the key intuition on which Kant built his deontological ethical theory. However, opponents say the consistency requires principles, and these are the enemies of truly good human behaviour, which involves Aristotle's 'particulars'.