Combining Philosophers

All the ideas for Thomas Grundmann, Michal Walicki and Sally Haslanger

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34 ideas

4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Post proved the consistency of propositional logic in 1921 [Walicki]
Propositional language can only relate statements as the same or as different [Walicki]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
Boolean connectives are interpreted as functions on the set {1,0} [Walicki]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]
The empty set avoids having to take special precautions in case members vanish [Walicki]
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
5. Theory of Logic / L. Paradox / 2. Aporiai
By using aporiai as his start, Aristotle can defer to the wise, as well as to the many [Haslanger]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki]
Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki]
The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki]
Two infinite ordinals can represent a single infinite cardinal [Walicki]
Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Inductive proof depends on the choice of the ordering [Walicki]
7. Existence / D. Theories of Reality / 1. Ontologies
Ontology disputes rest on more basic explanation disputes [Haslanger]
9. Objects / E. Objects over Time / 3. Three-Dimensionalism
The persistence of objects seems to be needed if the past is to explain the present [Haslanger]
Persistence makes change and its products intelligible [Haslanger]
9. Objects / E. Objects over Time / 5. Temporal Parts
We must explain change amongst 'momentary entities', or else the world is inexplicable [Haslanger]
If the things which exist prior to now are totally distinct, they need not have existed [Haslanger]
10. Modality / A. Necessity / 2. Nature of Necessity
Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
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]
14. Science / D. Explanation / 2. Types of Explanation / g. Causal explanations
Natural explanations give the causal interconnections [Haslanger]
14. Science / D. Explanation / 2. Types of Explanation / j. Explanations by reduction
Best explanations, especially natural ones, need grounding, notably by persistent objects [Haslanger]