Combining Texts

All the ideas for 'On Divination', 'On Formally Undecidable Propositions' and 'How Things Persist'

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58 ideas

1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
Philosophers are good at denying the obvious [Hawley]
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 / F. Referring in Logic / 1. Naming / b. Names as descriptive
Part of the sense of a proper name is a criterion of the thing's identity [Hawley]
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]
7. Existence / C. Structure of Existence / 5. Supervenience / d. Humean supervenience
A homogeneous rotating disc should be undetectable according to Humean supervenience [Hawley]
7. Existence / D. Theories of Reality / 10. Vagueness / b. Vagueness of reality
Non-linguistic things cannot be indeterminate, because they don't have truth-values at all [Hawley]
Maybe for the world to be vague, it must be vague in its foundations? [Hawley]
7. Existence / D. Theories of Reality / 10. Vagueness / c. Vagueness as ignorance
Epistemic vagueness seems right in the case of persons [Hawley]
7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness
Supervaluation refers to one vaguely specified thing, through satisfaction by everything in some range [Hawley]
Supervaluationism takes what the truth-value would have been if indecision was resolved [Hawley]
8. Modes of Existence / B. Properties / 1. Nature of Properties
Maybe the only properties are basic ones like charge, mass and spin [Hawley]
9. Objects / A. Existence of Objects / 1. Physical Objects
An object is 'natural' if its stages are linked by certain non-supervenient relations [Hawley]
9. Objects / B. Unity of Objects / 3. Unity Problems / b. Cat and its tail
Are sortals spatially maximal - so no cat part is allowed to be a cat? [Hawley]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
The modal features of statue and lump are disputed; when does it stop being that statue? [Hawley]
Perdurantists can adopt counterpart theory, to explain modal differences of identical part-sums [Hawley]
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
Vagueness is either in our knowledge, in our talk, or in reality [Hawley]
Indeterminacy in objects and in properties are not distinct cases [Hawley]
9. Objects / C. Structure of Objects / 6. Constitution of an Object
The constitution theory is endurantism plus more than one object in a place [Hawley]
Constitution theory needs sortal properties like 'being a sweater' to distinguish it from its thread [Hawley]
If the constitution view says thread and sweater are two things, why do we talk of one thing? [Hawley]
9. Objects / E. Objects over Time / 2. Objects that Change
'Adverbialism' explains change by saying an object has-at-some-time a given property [Hawley]
Presentism solves the change problem: the green banana ceases, so can't 'relate' to the yellow one [Hawley]
The problem of change arises if there must be 'identity' of a thing over time [Hawley]
9. Objects / E. Objects over Time / 3. Three-Dimensionalism
Endurance theory can relate properties to times, or timed instantiations to properties [Hawley]
Endurance is a sophisticated theory, covering properties, instantiation and time [Hawley]
9. Objects / E. Objects over Time / 4. Four-Dimensionalism
How does perdurance theory explain our concern for our own future selves? [Hawley]
Perdurance needs an atemporal perspective, to say that the object 'has' different temporal parts [Hawley]
If an object is the sum of all of its temporal parts, its mass is staggeringly large! [Hawley]
Perdurance says things are sums of stages; Stage Theory says each stage is the thing [Hawley]
If a life is essentially the sum of its temporal parts, it couldn't be shorter or longer than it was? [Hawley]
9. Objects / E. Objects over Time / 5. Temporal Parts
Stage Theory seems to miss out the link between stages of the same object [Hawley]
Stage Theory says every stage is a distinct object, which gives too many objects [Hawley]
An isolated stage can't be a banana (which involves suitable relations to other stages) [Hawley]
Stages of one thing are related by extrinsic counterfactual and causal relations [Hawley]
The stages of Stage Theory seem too thin to populate the world, or to be referred to [Hawley]
Stages must be as fine-grained in length as change itself, so any change is a new stage [Hawley]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
If two things might be identical, there can't be something true of one and false of the other [Hawley]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
To decide whether something is a counterpart, we need to specify a relevant sortal concept [Hawley]
16. Persons / D. Continuity of the Self / 5. Concerns of the Self
On any theory of self, it is hard to explain why we should care about our future selves [Hawley]
16. Persons / F. Free Will / 6. Determinism / a. Determinism
Whoever knows future causes knows everything that will be [Cicero]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
26. Natural Theory / C. Causation / 9. General Causation / c. Counterfactual causation
Causation is nothing more than the counterfactuals it grounds? [Hawley]
27. Natural Reality / D. Time / 3. Parts of Time / b. Instants
Time could be discrete (like integers) or dense (rationals) or continuous (reals) [Hawley]