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All the ideas for 'Thinking About Mathematics', 'On Formally Undecidable Propositions' and 'The Rationality of Science'

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50 ideas

1. Philosophy / G. Scientific Philosophy / 1. Aims of Science
We do not wish merely to predict, we also want to explain [Newton-Smith]
The real problem of science is how to choose between possible explanations [Newton-Smith]
For science to be rational, we must explain scientific change rationally [Newton-Smith]
1. Philosophy / G. Scientific Philosophy / 2. Positivism
Critics attack positivist division between theory and observation [Newton-Smith]
Positivists hold that theoretical terms change, but observation terms don't [Newton-Smith]
3. Truth / A. Truth Problems / 6. Verisimilitude
More truthful theories have greater predictive power [Newton-Smith]
Theories generate infinite truths and falsehoods, so they cannot be used to assess probability [Newton-Smith]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
Prior to Gödel we thought truth in mathematics consisted in provability [Gödel, by Quine]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Gödel show that the incompleteness of set theory was a necessity [Gödel, by Hallett,M]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
The limitations of axiomatisation were revealed by the incompleteness theorems [Gödel, by Koellner]
5. Theory of Logic / K. Features of Logics / 2. Consistency
Second Incompleteness: nice theories can't prove their own consistency [Gödel, by Smith,P]
5. Theory of Logic / K. Features of Logics / 3. Soundness
If soundness can't be proved internally, 'reflection principles' can be added to assert soundness [Gödel, by Halbach/Leigh]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
Gödel's First Theorem sabotages logicism, and the Second sabotages Hilbert's Programme [Smith,P on Gödel]
The undecidable sentence can be decided at a 'higher' level in the system [Gödel]
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
There can be no single consistent theory from which all mathematical truths can be derived [Gödel, by George/Velleman]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / h. Reals from Cauchy
Cauchy gave a formal definition of a converging sequence. [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Categories are the best foundation for mathematics [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Gödel showed that arithmetic is either incomplete or inconsistent [Gödel, by Rey]
First Incompleteness: arithmetic must always be incomplete [Gödel, by Smith,P]
Arithmetical truth cannot be fully and formally derived from axioms and inference rules [Gödel, by Nagel/Newman]
Gödel's Second says that semantic consequence outruns provability [Gödel, by Hanna]
First Incompleteness: a decent consistent system is syntactically incomplete [Gödel, by George/Velleman]
Second Incompleteness: a decent consistent system can't prove its own consistency [Gödel, by George/Velleman]
There is a sentence which a theory can show is true iff it is unprovable [Gödel, by Smith,P]
'This system can't prove this statement' makes it unprovable either way [Gödel, by Clegg]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / f. Zermelo numbers
Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Numbers do not exist independently; the essence of a number is its relations to other numbers [Shapiro]
A 'system' is related objects; a 'pattern' or 'structure' abstracts the pure relations from them [Shapiro]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Logicism seems to be a non-starter if (as is widely held) logic has no ontology of its own [Shapiro]
6. Mathematics / C. Sources of Mathematics / 7. Formalism
Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro]
Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro]
Deductivism says mathematics is logical consequences of uninterpreted axioms [Shapiro]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / c. Conceptualism
Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
Realists are happy with impredicative definitions, which describe entities in terms of other existing entities [Gödel, by Shapiro]
'Impredicative' definitions refer to the thing being described [Shapiro]
10. Modality / C. Sources of Modality / 1. Sources of Necessity
De re necessity arises from the way the world is [Newton-Smith]
11. Knowledge Aims / A. Knowledge / 4. Belief / a. Beliefs
We must assess the truth of beliefs in identifying them [Newton-Smith]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Rationalism tries to apply mathematical methodology to all of knowledge [Shapiro]
13. Knowledge Criteria / E. Relativism / 6. Relativism Critique
Defeat relativism by emphasising truth and reference, not meaning [Newton-Smith]
14. Science / A. Basis of Science / 1. Observation
A full understanding of 'yellow' involves some theory [Newton-Smith]
14. Science / A. Basis of Science / 5. Anomalies
All theories contain anomalies, and so are falsified! [Newton-Smith]
The anomaly of Uranus didn't destroy Newton's mechanics - it led to Neptune's discovery [Newton-Smith]
Anomalies are judged against rival theories, and support for the current theory [Newton-Smith]
14. Science / B. Scientific Theories / 1. Scientific Theory
Why should it matter whether or not a theory is scientific? [Newton-Smith]
14. Science / B. Scientific Theories / 5. Commensurability
If theories are really incommensurable, we could believe them all [Newton-Smith]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
20. Action / C. Motives for Action / 3. Acting on Reason / c. Reasons as causes
Explaining an action is showing that it is rational [Newton-Smith]