Combining Texts

All the ideas for 'fragments/reports', 'On Formally Undecidable Propositions' and 'On Eternal and Immutable Morality'

expand these ideas     |    start again     |     specify just one area for these texts


28 ideas

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 / 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 / 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 / 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]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / c. Tabula rasa
If the soul were a tabula rasa, with no innate ideas, there could be no moral goodness or justice [Cudworth]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
Senses cannot judge one another, so what judges senses cannot be a sense, but must be superior [Cudworth]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
17. Mind and Body / E. Mind as Physical / 7. Anti-Physicalism / a. Physicalism critique
Sense is fixed in the material form, and so can't grasp abstract universals [Cudworth]
22. Metaethics / B. Value / 1. Nature of Value / c. Objective value
Keeping promises and contracts is an obligation of natural justice [Cudworth]
25. Social Practice / D. Justice / 2. The Law / c. Natural law
Obligation to obey all positive laws is older than all laws [Cudworth]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / c. Ultimate substances
Pherecydes said the first principle and element is earth [Pherecydes, by Sext.Empiricus]
28. God / A. Divine Nature / 4. Divine Contradictions
An omnipotent will cannot make two things equal or alike if they aren't [Cudworth]
28. God / A. Divine Nature / 6. Divine Morality / d. God decrees morality
If the will and pleasure of God controls justice, then anything wicked or unjust would become good if God commanded it [Cudworth]
The requirement that God must be obeyed must precede any authority of God's commands [Cudworth]
29. Religion / D. Religious Issues / 2. Immortality / a. Immortality
Pherecydes was the first to say that the soul is eternal [Pherecydes, by Cicero]