Combining Texts

All the ideas for 'Analyzing Modality', 'Essays on Intellectual Powers 1: Preliminary' and 'Principia Mathematica'

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44 ideas

4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
The best known axiomatization of PL is Whitehead/Russell, with four axioms and two rules [Russell/Whitehead, by Hughes/Cresswell]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
Russell saw Reducibility as legitimate for reducing classes to logic [Linsky,B on Russell/Whitehead]
4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory
Russell denies extensional sets, because the null can't be a collection, and the singleton is just its element [Russell/Whitehead, by Shapiro]
We regard classes as mere symbolic or linguistic conveniences [Russell/Whitehead]
5. Theory of Logic / B. Logical Consequence / 7. Strict Implication
Lewis's 'strict implication' preserved Russell's confusion of 'if...then' with implication [Quine on Russell/Whitehead]
Russell's implication means that random sentences imply one another [Lewis,CI on Russell/Whitehead]
5. Theory of Logic / C. Ontology of Logic / 1. Ontology of Logic
Russell unusually saw logic as 'interpreted' (though very general, and neutral) [Russell/Whitehead, by Linsky,B]
5. Theory of Logic / E. Structures of Logic / 6. Relations in Logic
In 'Principia' a new abstract theory of relations appeared, and was applied [Russell/Whitehead, by Gödel]
5. Theory of Logic / G. Quantification / 3. Objectual Quantification
'All horses' either picks out the horses, or the things which are horses [Jubien]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts
A real number is the class of rationals less than the number [Russell/Whitehead, by Shapiro]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / a. Defining numbers
Russell takes numbers to be classes, but then reduces the classes to numerical quantifiers [Russell/Whitehead, by Bostock]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Russell and Whitehead were not realists, but embraced nearly all of maths in logic [Russell/Whitehead, by Friend]
Russell and Whitehead took arithmetic to be higher-order logic [Russell/Whitehead, by Hodes]
'Principia' lacks a precise statement of the syntax [Gödel on Russell/Whitehead]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / b. Type theory
The ramified theory of types used propositional functions, and covered bound variables [Russell/Whitehead, by George/Velleman]
The Russell/Whitehead type theory was limited, and was not really logic [Friend on Russell/Whitehead]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
In 'Principia Mathematica', logic is exceeded in the axioms of infinity and reducibility, and in the domains [Bernays on Russell/Whitehead]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / a. Constructivism
Russell and Whitehead consider the paradoxes to indicate that we create mathematical reality [Russell/Whitehead, by Friend]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
To avoid vicious circularity Russell produced ramified type theory, but Ramsey simplified it [Russell/Whitehead, by Shapiro]
9. Objects / A. Existence of Objects / 1. Physical Objects
Being a physical object is our most fundamental category [Jubien]
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
Haecceities implausibly have no qualities [Jubien]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
An object is identical with itself, and no different indiscernible object can share that [Russell/Whitehead, by Adams,RM]
10. Modality / A. Necessity / 11. Denial of Necessity
De re necessity is just de dicto necessity about object-essences [Jubien]
10. Modality / C. Sources of Modality / 5. Modality from Actuality
Modal propositions transcend the concrete, but not the actual [Jubien]
Your properties, not some other world, decide your possibilities [Jubien]
Modal truths are facts about parts of this world, not about remote maximal entities [Jubien]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
We have no idea how many 'possible worlds' there might be [Jubien]
If other worlds exist, then they are scattered parts of the actual world [Jubien]
If all possible worlds just happened to include stars, their existence would be necessary [Jubien]
If there are no other possible worlds, do we then exist necessarily? [Jubien]
Possible worlds just give parallel contingencies, with no explanation at all of necessity [Jubien]
Worlds don't explain necessity; we use necessity to decide on possible worlds [Jubien]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
We mustn't confuse a similar person with the same person [Jubien]
12. Knowledge Sources / E. Direct Knowledge / 1. Common Sense
Many truths seem obvious, and point to universal agreement - which is what we find [Reid]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
Russell showed, through the paradoxes, that our basic logical intuitions are self-contradictory [Russell/Whitehead, by Gödel]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
The multiple relations theory says assertions about propositions are about their ingredients [Russell/Whitehead, by Linsky,B]
A judgement is a complex entity, of mind and various objects [Russell/Whitehead]
The meaning of 'Socrates is human' is completed by a judgement [Russell/Whitehead]
The multiple relation theory of judgement couldn't explain the unity of sentences [Morris,M on Russell/Whitehead]
Only the act of judging completes the meaning of a statement [Russell/Whitehead]
18. Thought / C. Content / 2. Ideas
Only philosophers treat ideas as objects [Reid]
19. Language / A. Nature of Meaning / 9. Ambiguity
The ambiguity of words impedes the advancement of knowledge [Reid]
19. Language / D. Propositions / 3. Concrete Propositions
Propositions as objects of judgement don't exist, because we judge several objects, not one [Russell/Whitehead]
26. Natural Theory / C. Causation / 1. Causation
Similar effects come from similar causes, and causes are only what are sufficient for the effects [Reid]