Combining Philosophers

All the ideas for Menedemus, Gerhard Gentzen and Henry Laycock

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17 ideas

5. Theory of Logic / A. Overview of Logic / 2. History of Logic
Gentzen introduced a natural deduction calculus (NK) in 1934 [Gentzen, by Read]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna]
The logical connectives are 'defined' by their introduction rules [Gentzen]
Each logical symbol has an 'introduction' rule to define it, and hence an 'elimination' rule [Gentzen]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
If plural variables have 'some values', then non-count variables have 'some value' [Laycock]
5. Theory of Logic / G. Quantification / 6. Plural Quantification
Plurals are semantical but not ontological [Laycock]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
Some non-count nouns can be used for counting, as in 'several wines' or 'fewer cheeses' [Laycock]
Some apparent non-count words can take plural forms, such as 'snows' or 'waters' [Laycock]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave]
7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff
The category of stuff does not suit reference [Laycock]
Descriptions of stuff are neither singular aggregates nor plural collections [Laycock]
7. Existence / C. Structure of Existence / 8. Stuff / b. Mixtures
We shouldn't think some water retains its identity when it is mixed with air [Laycock]
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
Parts must be of the same very general type as the wholes [Laycock]
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
'Humility is a virtue' has an abstract noun, but 'water is a liquid' has a generic concrete noun [Laycock]
19. Language / B. Reference / 1. Reference theories
It is said that proper reference is our intellectual link with the world [Laycock]
23. Ethics / A. Egoism / 1. Ethical Egoism
The greatest good is not the achievement of desire, but to desire what is proper [Menedemus, by Diog. Laertius]