Combining Philosophers

All the ideas for Rescher,N/Oppenheim,P, Michal Walicki and Hamid Vahid

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29 ideas

4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Post proved the consistency of propositional logic in 1921 [Walicki]
Propositional language can only relate statements as the same or as different [Walicki]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
Boolean connectives are interpreted as functions on the set {1,0} [Walicki]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]
The empty set avoids having to take special precautions in case members vanish [Walicki]
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki]
Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki]
The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki]
Two infinite ordinals can represent a single infinite cardinal [Walicki]
Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Inductive proof depends on the choice of the ordering [Walicki]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
A whole must have one characteristic, an internal relation, and a structure [Rescher/Oppenheim]
10. Modality / A. Necessity / 2. Nature of Necessity
Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
11. Knowledge Aims / A. Knowledge / 1. Knowledge
Maybe there is plain 'animal' knowledge, and clearly justified 'reflective' knowledge [Vahid]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / a. Justification issues
Epistemic is normally marked out from moral or pragmatic justifications by its truth-goal [Vahid]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / a. Pro-internalism
'Mentalist' internalism seems to miss the main point, if it might not involve an agent's access [Vahid]
Strong access internalism needs actual awareness; weak versions need possibility of access [Vahid]
Maybe we need access to our justification, and also to know why it justifies [Vahid]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / b. Pro-externalism
Internalism in epistemology over-emphasises deliberation about beliefs [Vahid]
13. Knowledge Criteria / C. External Justification / 1. External Justification
Externalism may imply that identical mental states might go with different justifications [Vahid]
13. Knowledge Criteria / C. External Justification / 4. Tracking the Facts
With a counterfactual account of the causal theory, we get knowledge as tracking or sensitive to truth [Vahid]
13. Knowledge Criteria / C. External Justification / 10. Anti External Justification
Externalism makes the acquisition of knowledge too easy? [Vahid]