Combining Philosophers

All the ideas for Hermarchus, Fred Sommers and Alan Musgrave

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19 ideas

3. Truth / B. Truthmakers / 5. What Makes Truths / a. What makes truths
Truthmakers are facts 'of' a domain, not something 'in' the domain [Sommers]
4. Formal Logic / A. Syllogistic Logic / 3. Term Logic
'Predicable' terms come in charged pairs, with one the negation of the other [Sommers, by Engelbretsen]
Logic which maps ordinary reasoning must be transparent, and free of variables [Sommers]
5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
The If-thenist view only seems to work for the axiomatised portions of mathematics [Musgrave]
Perhaps If-thenism survives in mathematics if we stick to first-order logic [Musgrave]
5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
Predicate logic has to spell out that its identity relation '=' is an equivalent relation [Sommers]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
Translating into quantificational idiom offers no clues as to how ordinary thinkers reason [Sommers]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / c. not
Sommers promotes the old idea that negation basically refers to terms [Sommers, by Engelbretsen]
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
Predicates form a hierarchy, from the most general, down to names at the bottom [Sommers]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Logical truths may contain non-logical notions, as in 'all men are men' [Musgrave]
A statement is logically true if it comes out true in all interpretations in all (non-empty) domains [Musgrave]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
No two numbers having the same successor relies on the Axiom of Infinity [Musgrave]
6. Mathematics / C. Sources of Mathematics / 7. Formalism
Formalism seems to exclude all creative, growing mathematics [Musgrave]
Formalism is a bulwark of logical positivism [Musgrave]
7. Existence / D. Theories of Reality / 2. Realism
Unfortunately for realists, modern logic cannot say that some fact exists [Sommers]
7. Existence / E. Categories / 1. Categories
Categories can't overlap; they are either disjoint, or inclusive [Sommers, by Westerhoff]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
Logical positivists adopted an If-thenist version of logicism about numbers [Musgrave]
19. Language / B. Reference / 1. Reference theories
In standard logic, names are the only way to refer [Sommers]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]