Combining Texts

All the ideas for 'Principia Mathematica', 'Draft Statement of Human Obligations' and 'Discourse on Metaphysics'

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50 ideas

2. Reason / B. Laws of Thought / 6. Ockham's Razor
Reason avoids multiplying hypotheses or principles [Leibniz]
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]
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 took arithmetic to be higher-order logic [Russell/Whitehead, by Hodes]
Russell and Whitehead were not realists, but embraced nearly all of maths in logic [Russell/Whitehead, by Friend]
'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]
8. Modes of Existence / C. Powers and Dispositions / 1. Powers
The immediate cause of movements is more real [than geometry] [Leibniz]
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
The complete notion of a substance implies all of its predicates or attributes [Leibniz]
9. Objects / B. Unity of Objects / 2. Substance / c. Types of substance
Substances mirror God or the universe, each from its own viewpoint [Leibniz]
9. Objects / C. Structure of Objects / 2. Hylomorphism / b. Form as principle
Forms are of no value in physics, but are indispensable in metaphysics [Leibniz]
9. Objects / D. Essence of Objects / 1. Essences of Objects
Subjects include predicates, so full understanding of subjects reveals all the predicates [Leibniz]
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 / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
Leibniz is some form of haecceitist [Leibniz, by Cover/O'Leary-Hawthorne]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
Knowledge doesn't just come from the senses; we know the self, substance, identity, being etc. [Leibniz]
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]
16. Persons / D. Continuity of the Self / 2. Mental Continuity / a. Memory is Self
If a person's memories became totally those of the King of China, he would be the King of China [Leibniz]
16. Persons / F. Free Will / 1. Nature of Free Will
Future contingent events are certain, because God foresees them, but that doesn't make them necessary [Leibniz]
16. Persons / F. Free Will / 6. Determinism / a. Determinism
People argue for God's free will, but it isn't needed if God acts in perfection following supreme reason [Leibniz]
17. Mind and Body / A. Mind-Body Dualism / 4. Occasionalism
Mind and body can't influence one another, but God wouldn't intervene in the daily routine [Leibniz]
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]
19. Language / D. Propositions / 3. Concrete Propositions
Propositions as objects of judgement don't exist, because we judge several objects, not one [Russell/Whitehead]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / a. Preconditions for ethics
Animals lack morality because they lack self-reflection [Leibniz]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / a. Idealistic ethics
Every human yearns for an unattainable transcendent good [Weil]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
Where human needs are satisfied we find happiness, friendship and beauty [Weil]
23. Ethics / C. Virtue Theory / 3. Virtues / h. Respect
We cannot equally respect what is unequal, so equal respect needs a shared ground [Weil]
23. Ethics / F. Existentialism / 4. Boredom
Life needs risks to avoid sickly boredom [Weil]
24. Political Theory / B. Nature of a State / 4. Citizenship
We all need to partipate in public tasks, and take some initiative [Weil]
24. Political Theory / D. Ideologies / 3. Conservatism
We need both equality (to attend to human needs) and hierarchy (as a scale of responsibilities) [Weil]
25. Social Practice / A. Freedoms / 3. Free speech
Deliberate public lying should be punished [Weil]
25. Social Practice / A. Freedoms / 6. Political freedom
We have liberty in the space between nature and accepted authority [Weil]
25. Social Practice / C. Rights / 4. Property rights
People need personal and collective property, and a social class lacking property is shameful [Weil]
25. Social Practice / D. Justice / 3. Punishment / d. Reform of offenders
Crime should be punished, to bring the perpetrator freely back to morality [Weil]
28. God / A. Divine Nature / 6. Divine Morality / c. God is the good
Attention to a transcendent reality motivates a duty to foster the good of humanity [Weil]