Combining Texts

All the ideas for 'That Politics may be reduced to a Science', 'First-order Logic, 2nd-order, Completeness' and 'Philosophy of Logics'

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15 ideas

3. Truth / C. Correspondence Truth / 3. Correspondence Truth critique
Logical truth seems much less likely to 'correspond to the facts' than factual truth does [Haack]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
The same sentence could be true in one language and meaningless in another, so truth is language-relative [Haack]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg]
Henkin semantics has a second domain of predicates and relations (in upper case) [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 / C. Virtue Theory / 4. External Goods / d. Friendship
Friendship without community spirit misses out on the main part of virtue [Hume]
24. Political Theory / B. Nature of a State / 3. Constitutions
It would be absurd if even a free constitution did not impose restraints, for the public good [Hume]
24. Political Theory / C. Ruling a State / 2. Leaders / d. Elites
Nobility either share in the power of the whole, or they compose the power of the whole [Hume]