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All the ideas for 'Philosophy of Mathematics', 'In Defence of Pure Reason' and 'Gravity and Grace (9 extracts)'

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75 ideas

1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Philosophy is a priori if it is anything [Bonjour]
2. Reason / A. Nature of Reason / 3. Pure Reason
Perceiving necessary connections is the essence of reasoning [Bonjour]
2. Reason / A. Nature of Reason / 6. Coherence
Coherence can't be validated by appeal to coherence [Bonjour]
2. Reason / D. Definition / 8. Impredicative Definition
Impredicative definitions are wrong, because they change the set that is being defined? [Bostock]
3. Truth / A. Truth Problems / 3. Value of Truth
We seek truth only because it is good [Weil]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Classical interdefinitions of logical constants and quantifiers is impossible in intuitionism [Bostock]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
There is no single agreed structure for set theory [Bostock]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / a. Types of set
A 'proper class' cannot be a member of anything [Bostock]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
We could add axioms to make sets either as small or as large as possible [Bostock]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice relies on reference to sets that we are unable to describe [Bostock]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / f. Limitation of Size
Replacement enforces a 'limitation of size' test for the existence of sets [Bostock]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
The completeness of first-order logic implies its compactness [Bostock]
First-order logic is not decidable: there is no test of whether any formula is valid [Bostock]
5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
Substitutional quantification is just standard if all objects in the domain have a name [Bostock]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
The Deduction Theorem is what licenses a system of natural deduction [Bostock]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / c. Berry's paradox
Berry's Paradox considers the meaning of 'The least number not named by this name' [Bostock]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
ω + 1 is a new ordinal, but its cardinality is unchanged [Bostock]
Each addition changes the ordinality but not the cardinality, prior to aleph-1 [Bostock]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
A cardinal is the earliest ordinal that has that number of predecessors [Bostock]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / f. Cardinal numbers
Aleph-1 is the first ordinal that exceeds aleph-0 [Bostock]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
Instead of by cuts or series convergence, real numbers could be defined by axioms [Bostock]
The number of reals is the number of subsets of the natural numbers [Bostock]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts
For Eudoxus cuts in rationals are unique, but not every cut makes a real number [Bostock]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / k. Infinitesimals
Infinitesimals are not actually contradictory, because they can be non-standard real numbers [Bostock]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Modern axioms of geometry do not need the real numbers [Bostock]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
The Peano Axioms describe a unique structure [Bostock]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / d. Hume's Principle
There are many criteria for the identity of numbers [Bostock]
Hume's Principle is a definition with existential claims, and won't explain numbers [Bostock]
Many things will satisfy Hume's Principle, so there are many interpretations of it [Bostock]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
Frege makes numbers sets to solve the Caesar problem, but maybe Caesar is a set! [Bostock]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
Numbers can't be positions, if nothing decides what position a given number has [Bostock]
Structuralism falsely assumes relations to other numbers are numbers' only properties [Bostock]
6. Mathematics / C. Sources of Mathematics / 3. Mathematical Nominalism
Nominalism about mathematics is either reductionist, or fictionalist [Bostock]
Nominalism as based on application of numbers is no good, because there are too many applications [Bostock]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / b. Indispensability of mathematics
Actual measurement could never require the precision of the real numbers [Bostock]
6. Mathematics / C. Sources of Mathematics / 5. Numbers as Adjectival
Ordinals are mainly used adjectively, as in 'the first', 'the second'... [Bostock]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / b. Type theory
Simple type theory has 'levels', but ramified type theory has 'orders' [Bostock]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
Neo-logicists agree that HP introduces number, but also claim that it suffices for the job [Bostock]
Neo-logicists meet the Caesar problem by saying Hume's Principle is unique to number [Bostock]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Treating numbers as objects doesn't seem like logic, since arithmetic fixes their totality [Bostock]
Many crucial logicist definitions are in fact impredicative [Bostock]
If Hume's Principle is the whole story, that implies structuralism [Bostock]
6. Mathematics / C. Sources of Mathematics / 9. Fictional Mathematics
Higher cardinalities in sets are just fairy stories [Bostock]
A fairy tale may give predictions, but only a true theory can give explanations [Bostock]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / c. Conceptualism
The best version of conceptualism is predicativism [Bostock]
Conceptualism fails to grasp mathematical properties, infinity, and objective truth values [Bostock]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
The usual definitions of identity and of natural numbers are impredicative [Bostock]
If abstracta only exist if they are expressible, there can only be denumerably many of them [Bostock]
Predicativism makes theories of huge cardinals impossible [Bostock]
If mathematics rests on science, predicativism may be the best approach [Bostock]
If we can only think of what we can describe, predicativism may be implied [Bostock]
The predicativity restriction makes a difference with the real numbers [Bostock]
10. Modality / B. Possibility / 1. Possibility
The concept of possibility is prior to that of necessity [Bonjour]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Moderate rationalists believe in fallible a priori justification [Bonjour]
Our rules of thought can only be judged by pure rational insight [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / d. Rational foundations
A priori justification can vary in degree [Bonjour]
A priori justification requires understanding but no experience [Bonjour]
You can't explain away a priori justification as analyticity, and you can't totally give it up [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
The induction problem blocks any attempted proof of physical statements [Bonjour]
13. Knowledge Criteria / C. External Justification / 1. External Justification
Externalist theories of justification don't require believers to have reasons for their beliefs [Bonjour]
13. Knowledge Criteria / C. External Justification / 10. Anti External Justification
Externalism means we have no reason to believe, which is strong scepticism [Bonjour]
14. Science / C. Induction / 2. Aims of Induction
Induction must go beyond the evidence, in order to explain why the evidence occurred [Bonjour]
18. Thought / C. Content / 1. Content
All thought represents either properties or indexicals [Bonjour]
19. Language / F. Communication / 2. Assertion
In logic a proposition means the same when it is and when it is not asserted [Bostock]
19. Language / F. Communication / 6. Interpreting Language / b. Indeterminate translation
Indeterminacy of translation is actually indeterminacy of meaning and belief [Bonjour]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / a. Idealistic ethics
Beauty, goodness and truth are only achieved by applying full attention [Weil]
22. Metaethics / C. The Good / 1. Goodness / a. Form of the Good
The good is a nothingness, and yet real [Weil]
There are two goods - the absolute good we want, and the reachable opposite of evil [Weil]
24. Political Theory / C. Ruling a State / 1. Social Power
The essence of power is illusory prestige [Weil]
24. Political Theory / D. Ideologies / 1. Ideology
A group is only dangerous if it endorses an abstract entity [Weil]
24. Political Theory / D. Ideologies / 2. Anarchism
Our only social duty is to try to limit evil [Weil]
24. Political Theory / D. Ideologies / 9. Communism
The collective is the one and only object of false idolatry [Weil]
24. Political Theory / D. Ideologies / 14. Nationalism
Charity is the only love, and you can feel that for a country (a place with traditions), but not a nation [Weil]
25. Social Practice / A. Freedoms / 1. Slavery
If effort is from necessity rather than for a good, it is slavery [Weil]
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
The soul is the intrinsic value of a human [Weil]