Combining Texts

All the ideas for 'Principles of Theoretical Logic', 'First-order Logic, 2nd-order, Completeness' and 'Statements about Universals'

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13 ideas

4. Formal Logic / C. Predicate Calculus PC / 1. Predicate Calculus PC
The first clear proof of the consistency of the first order predicate logic was in 1928 [Hilbert/Ackermann, by Walicki]
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]
8. Modes of Existence / D. Universals / 4. Uninstantiated Universals
Nominalists cannot translate 'red resembles pink more than blue' into particulars [Jackson]
8. Modes of Existence / E. Nominalism / 2. Resemblance Nominalism
Colour resemblance isn't just resemblance between things; 'colour' must be mentioned [Jackson]