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All the ideas for 'On the Question of Absolute Undecidability', 'Concluding Unscientific Postscript' and 'Philosophical Logic'

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49 ideas

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / d. Philosophy as puzzles
I conceived it my task to create difficulties everywhere [Kierkegaard]
1. Philosophy / D. Nature of Philosophy / 8. Humour
Wherever there is painless contradiction there is also comedy [Kierkegaard]
3. Truth / A. Truth Problems / 2. Defining Truth
Kierkegaard's truth draws on authenticity, fidelity and honesty [Kierkegaard, by Carlisle]
3. Truth / A. Truth Problems / 3. Value of Truth
Pure truth is for infinite beings only; I prefer endless striving for truth [Kierkegaard]
3. Truth / A. Truth Problems / 8. Subjective Truth
The highest truth we can get is uncertainty held fast by an inward passion [Kierkegaard]
4. Formal Logic / D. Modal Logic ML / 6. Temporal Logic
With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess]
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
The temporal Barcan formulas fix what exists, which seems absurd [Burgess]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Is classical logic a part of intuitionist logic, or vice versa? [Burgess]
It is still unsettled whether standard intuitionist logic is complete [Burgess]
4. Formal Logic / E. Nonclassical Logics / 5. Relevant Logic
Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner]
'Reflection principles' say the whole truth about sets can't be captured [Koellner]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Classical logic neglects the non-mathematical, such as temporality or modality [Burgess]
The Cut Rule expresses the classical idea that entailment is transitive [Burgess]
Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess]
5. Theory of Logic / A. Overview of Logic / 9. Philosophical Logic
Philosophical logic is a branch of logic, and is now centred in computer science [Burgess]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
Formalising arguments favours lots of connectives; proving things favours having very few [Burgess]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / e. or
Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
All occurrences of variables in atomic formulas are free [Burgess]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions
The denotation of a definite description is flexible, rather than rigid [Burgess]
5. Theory of Logic / H. Proof Systems / 1. Proof Systems
'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess]
5. Theory of Logic / H. Proof Systems / 6. Sequent Calculi
The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess]
We can build one expanding sequence, instead of a chain of deductions [Burgess]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess]
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Models leave out meaning, and just focus on truth values [Burgess]
We only need to study mathematical models, since all other models are isomorphic to these [Burgess]
We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
We have no argument to show a statement is absolutely undecidable [Koellner]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess]
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]
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]
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]
10. Modality / A. Necessity / 4. De re / De dicto modality
De re modality seems to apply to objects a concept intended for sentences [Burgess]
10. Modality / A. Necessity / 6. Logical Necessity
General consensus is S5 for logical modality of validity, and S4 for proof [Burgess]
Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess]
It is doubtful whether the negation of a conditional has any clear meaning [Burgess]
16. Persons / B. Nature of the Self / 2. Ethical Self
The real subject is ethical, not cognitive [Kierkegaard]
23. Ethics / F. Existentialism / 1. Existentialism
While big metaphysics is complete without ethics, personal philosophy emphasises ethics [Kierkegaard]
Speculative philosophy loses the individual in a vast vision of humanity [Kierkegaard]
23. Ethics / F. Existentialism / 6. Authentic Self
People want to lose themselves in movements and history, instead of being individuals [Kierkegaard]
Becoming what one is is a huge difficulty, because we strongly aspire to be something else [Kierkegaard]
28. God / A. Divine Nature / 2. Divine Nature
God does not think or exist; God creates, and is eternal [Kierkegaard]
28. God / B. Proving God / 3. Proofs of Evidence / d. Religious Experience
God cannot be demonstrated objectively, because God is a subject, only existing inwardly [Kierkegaard]
28. God / C. Attitudes to God / 2. Pantheism
Pantheism destroys the distinction between good and evil [Kierkegaard]
29. Religion / D. Religious Issues / 1. Religious Commitment / e. Fideism
Faith is the highest passion in the sphere of human subjectivity [Kierkegaard]
Without risk there is no faith [Kierkegaard]