Combining Philosophers

All the ideas for Harold Noonan, Thomas Grundmann and Feferman / Feferman

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


28 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 7. Decidability
'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
It is controversial whether only 'numerical identity' allows two things to be counted as one [Noonan]
9. Objects / E. Objects over Time / 4. Four-Dimensionalism
I could have died at five, but the summation of my adult stages could not [Noonan]
9. Objects / E. Objects over Time / 5. Temporal Parts
Stage theorists accept four-dimensionalism, but call each stage a whole object [Noonan]
9. Objects / F. Identity among Objects / 2. Defining Identity
Problems about identity can't even be formulated without the concept of identity [Noonan]
Identity is usually defined as the equivalence relation satisfying Leibniz's Law [Noonan]
Identity definitions (such as self-identity, or the smallest equivalence relation) are usually circular [Noonan]
Identity can only be characterised in a second-order language [Noonan]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
Indiscernibility is basic to our understanding of identity and distinctness [Noonan]
Leibniz's Law must be kept separate from the substitutivity principle [Noonan]
11. Knowledge Aims / B. Certain Knowledge / 3. Fallibilism
Indefeasibility does not imply infallibility [Grundmann]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / c. Defeasibility
Can a defeater itself be defeated? [Grundmann]
Simple reliabilism can't cope with defeaters of reliably produced beliefs [Grundmann]
You can 'rebut' previous beliefs, 'undercut' the power of evidence, or 'reason-defeat' the truth [Grundmann]
Defeasibility theory needs to exclude defeaters which are true but misleading [Grundmann]
Knowledge requires that there are no facts which would defeat its justification [Grundmann]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
'Moderate' foundationalism has basic justification which is defeasible [Grundmann]