Combining Philosophers

All the ideas for Speussipus, Rudolph Carnap and Graeme Forbes

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54 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]
There must be a plausible epistemological theory alongside any metaphysical theory [Forbes,G]
1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
Metaphysics uses empty words, or just produces pseudo-statements [Carnap]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / a. Symbols of PL
The symbol 'ι' forms definite descriptions; (ιx)F(x) says 'the x which is such that F(x)' [Forbes,G]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Carnap defined consequence by contradiction, but this is unintuitive and changes with substitution [Tarski on Carnap]
5. Theory of Logic / C. Ontology of Logic / 4. Logic by Convention
Each person is free to build their own logic, just by specifying a syntax [Carnap]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / d. and
Is the meaning of 'and' given by its truth table, or by its introduction and elimination rules? [Forbes,G]
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 / 10. Vagueness / d. Vagueness as linguistic
Vagueness problems arise from applying sharp semantics to vague languages [Forbes,G]
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 / 5. Individuation / a. Individuation
In all instances of identity, there must be some facts to ensure the identity [Forbes,G]
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 / B. Unity of Objects / 2. Substance / c. Types of substance
Speusippus suggested underlying principles for every substance, and ended with a huge list [Speussipus, by Aristotle]
9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects
If we combined two clocks, it seems that two clocks may have become one clock. [Forbes,G]
9. Objects / D. Essence of Objects / 3. Individual Essences
Only individual essences will ground identities across worlds in other properties [Forbes,G, by Mackie,P]
An individual essence is a set of essential properties which only that object can have [Forbes,G]
Non-trivial individual essence is properties other than de dicto, or universal, or relational [Forbes,G]
9. Objects / D. Essence of Objects / 5. Essence as Kind
Essential properties depend on a category, and perhaps also on particular facts [Forbes,G]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
A property is essential iff the object would not exist if it lacked that property [Forbes,G]
Properties are trivially essential if they are not grounded in a thing's specific nature [Forbes,G]
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
Essential properties are those without which an object could not exist [Forbes,G]
A relation is essential to two items if it holds in every world where they exist [Forbes,G]
9. Objects / D. Essence of Objects / 7. Essence and Necessity / c. Essentials are necessary
Trivially essential properties are existence, self-identity, and de dicto necessities [Forbes,G]
9. Objects / D. Essence of Objects / 9. Essence and Properties
A property is 'extraneously essential' if it is had only because of the properties of other objects [Forbes,G]
9. Objects / D. Essence of Objects / 11. Essence of Artefacts
Same parts does not ensure same artefact, if those parts could constitute a different artefact [Forbes,G]
Artefacts have fuzzy essences [Forbes,G]
One might be essentialist about the original bronze from which a statue was made [Forbes,G]
9. Objects / E. Objects over Time / 12. Origin as Essential
An individual might change their sex in a world, but couldn't have differed in sex at origin [Forbes,G]
9. Objects / F. Identity among Objects / 1. Concept of Identity
Identities must hold because of other facts, which must be instrinsic [Forbes,G, by Mackie,P]
10. Modality / A. Necessity / 4. De re / De dicto modality
De re modal formulae, unlike de dicto, are sensitive to transworld identities [Forbes,G]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
In the truth-functional account a burnt-up match was soluble because it never entered water [Carnap]
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
De re necessity is a form of conceptual necessity, just as de dicto necessity is [Forbes,G]
The source of de dicto necessity is not concepts, but the actual properties of the thing [Forbes,G]
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
Unlike places and times, we cannot separate possible worlds from what is true at them [Forbes,G]
The problem with possible worlds realism is epistemological; we can't know properties of possible objects [Forbes,G]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Possible worlds are points of logical space, rather like other times than our own [Forbes,G]
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Transworld identity concerns the limits of possibility for ordinary things [Forbes,G]
The problem of transworld identity can be solved by individual essences [Forbes,G]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Counterpart theory is not good at handling the logic of identity [Forbes,G]
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
Haecceitism attributes to each individual a primitive identity or thisness [Forbes,G]
We believe in thisnesses, because we reject bizarre possibilities as not being about that individual [Forbes,G]
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 / 1. Scientific Theory
Carnap tried to define all scientific predicates in terms of primitive relations, using type theory [Carnap, by Button]
14. Science / B. Scientific Theories / 3. Instrumentalism
All linguistic forms in science are merely judged by their efficiency as instruments [Carnap]
14. Science / D. Explanation / 1. Explanation / b. Aims of explanation
Good explications are exact, fruitful, simple and similar to the explicandum [Carnap, by Salmon]
18. Thought / D. Concepts / 4. Structure of Concepts / g. Conceptual atomism
All concepts can be derived from a few basics, making possible one science of everything [Carnap, by Brody]
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
The intension of a sentence is the set of all possible worlds in which it is true [Carnap, by Kaplan]
19. Language / F. Communication / 6. Interpreting Language / a. Translation
All translation loses some content (but language does not create reality) [Carnap]
28. God / C. Attitudes to God / 5. Atheism
Speusippus said things were governed by some animal force rather than the gods [Speussipus, by Cicero]