Combining Philosophers

All the ideas for Thrasymachus, Marcus Rossberg and William Poundstone

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18 ideas

5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg]
Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg]
There are at least seven possible systems of semantics for second-order logic [Rossberg]
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
Logical consequence is intuitively semantic, and captured by model theory [Rossberg]
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
Γ |- S says S can be deduced from Γ; Γ |= S says a good model for Γ makes S true [Rossberg]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
In proof-theory, logical form is shown by the logical constants [Rossberg]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A model is a domain, and an interpretation assigning objects, predicates, relations etc. [Rossberg]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
If models of a mathematical theory are all isomorphic, it is 'categorical', with essentially one model [Rossberg]
5. Theory of Logic / K. Features of Logics / 4. Completeness
Completeness can always be achieved by cunning model-design [Rossberg]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
A deductive system is only incomplete with respect to a formal semantics [Rossberg]
23. Ethics / B. Contract Ethics / 1. Contractarianism
Self-interest can fairly divide a cake; first person cuts, second person chooses [Poundstone]
23. Ethics / B. Contract Ethics / 6. Game Theory
Formal game theory is about maximising or minimising numbers in tables [Poundstone]
The minimax theorem says a perfect game of opposed people always has a rational solution [Poundstone]
23. Ethics / B. Contract Ethics / 7. Prisoner's Dilemma
Two prisoners get the best result by being loyal, not by selfish betrayal [Poundstone]
The tragedy in prisoner's dilemma is when two 'nice' players misread each other [Poundstone]
23. Ethics / B. Contract Ethics / 8. Contract Strategies
Do unto others as you would have them do unto you - or else! [Poundstone]
TIT FOR TAT says cooperate at first, then do what the other player does [Poundstone]
28. God / C. Attitudes to God / 3. Deism
Clearly the gods ignore human affairs, or they would have given us justice [Thrasymachus]