Combining Texts

All the ideas for 'fragments/reports', 'Academica' and 'Alfred Tarski: life and logic'

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20 ideas

2. Reason / C. Styles of Reason / 1. Dialectic
Dialectic is speech cast in the form of logical argument [Cicero]
3. Truth / A. Truth Problems / 1. Truth
There cannot be more than one truth [Cicero]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Dialectic assumes that all statements are either true or false, but self-referential paradoxes are a big problem [Cicero]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 7. Decidability
'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
12. Knowledge Sources / B. Perception / 1. Perception
If we have complete healthy senses, what more could the gods give us? [Cicero]
12. Knowledge Sources / E. Direct Knowledge / 4. Memory
How can there be a memory of what is false? [Cicero]
13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism
Every true presentation can have a false one of the same quality [Cicero]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / c. Motivation for virtue
Virtues must be very detached, to avoid being motivated by pleasure [Cicero]
23. Ethics / C. Virtue Theory / 3. Virtues / a. Virtues
The cardinal virtues are theoretical (based on knowledge), and others are 'non-theoretical' [Hecato, by Dorandi]