Combining Texts

All the ideas for 'World and Essence', 'The Philosophy of Mathematics' and 'Empiricism, Semantics and Ontology'

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29 ideas

1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
No possible evidence could decide the reality of numbers, so it is a pseudo-question [Carnap]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
ZF set theory has variables which range over sets, 'equals' and 'member', and extensionality [Dummett]
The main alternative to ZF is one which includes looser classes as well as sets [Dummett]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Intuitionists reject excluded middle, not for a third value, but for possibility of proof [Dummett]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
First-order logic concerns objects; second-order adds properties, kinds, relations and functions [Dummett]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Logical truths and inference are characterized either syntactically or semantically [Dummett]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
Ordinals seem more basic than cardinals, since we count objects in sequence [Dummett]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
The number 4 has different positions in the naturals and the wholes, with the same structure [Dummett]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Questions about numbers are answered by analysis, and are analytic, and hence logically true [Carnap]
Logical positivists incorporated geometry into logicism, saying axioms are just definitions [Carnap, by Shapiro]
7. Existence / A. Nature of Existence / 4. Abstract Existence
Internal questions about abstractions are trivial, and external ones deeply problematic [Carnap, by Szabó]
7. Existence / D. Theories of Reality / 1. Ontologies
Existence questions are 'internal' (within a framework) or 'external' (concerning the whole framework) [Carnap]
7. Existence / D. Theories of Reality / 3. Reality
To be 'real' is to be an element of a system, so we cannot ask reality questions about the system itself [Carnap]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / a. Ontological commitment
A linguistic framework involves commitment to entities, so only commitment to the framework is in question [Carnap]
9. Objects / A. Existence of Objects / 4. Impossible objects
Plantinga proposes necessary existent essences as surrogates for the nonexistent things [Plantinga, by Stalnaker]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
The 'identity criteria' of a name are a group of essential and established facts [Plantinga]
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
'Being Socrates' and 'being identical with Socrates' characterise Socrates, so they are among his properties [Plantinga]
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
We only accept 'things' within a language with formation, testing and acceptance rules [Carnap]
9. Objects / D. Essence of Objects / 2. Types of Essence
Does Socrates have essential properties, plus a unique essence (or 'haecceity') which entails them? [Plantinga]
9. Objects / D. Essence of Objects / 9. Essence and Properties
Properties are 'trivially essential' if they are instantiated by every object in every possible world [Plantinga]
X is essentially P if it is P in every world, or in every X-world, or in the actual world (and not ¬P elsewhere) [Plantinga]
If a property is ever essential, can it only ever be an essential property? [Plantinga]
Essences are instantiated, and are what entails a thing's properties and lack of properties [Plantinga]
9. Objects / F. Identity among Objects / 5. Self-Identity
Does 'being identical with Socrates' name a property? I can think of no objections to it [Plantinga]
10. Modality / A. Necessity / 4. De re / De dicto modality
'De re' modality is as clear as 'de dicto' modality, because they are logically equivalent [Plantinga]
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
We can imagine being beetles or alligators, so it is possible we might have such bodies [Plantinga]
12. Knowledge Sources / D. Empiricism / 1. Empiricism
Empiricists tend to reject abstract entities, and to feel sympathy with nominalism [Carnap]
12. Knowledge Sources / D. Empiricism / 3. Pragmatism
New linguistic claims about entities are not true or false, but just expedient, fruitful or successful [Carnap]
14. Science / B. Scientific Theories / 3. Instrumentalism
All linguistic forms in science are merely judged by their efficiency as instruments [Carnap]