Combining Texts

All the ideas for 'A Résumé of Metaphysics', 'A Tour through Mathematical Logic' and 'Truth and Ontology'

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


48 ideas

3. Truth / B. Truthmakers / 2. Truthmaker Relation
A ground must be about its truth, and not just necessitate it [Merricks]
3. Truth / B. Truthmakers / 5. What Makes Truths / a. What makes truths
Truthmaker needs truths to be 'about' something, and that is often unclear [Merricks]
3. Truth / B. Truthmakers / 5. What Makes Truths / b. Objects make truths
If a ball changes from red to white, Truthmaker says some thing must make the change true [Merricks]
Truthmaker says if an entity is removed, some nonexistence truthmaker must replace it [Merricks]
If Truthmaker says each truth is made by the existence of something, the theory had de re modality at is core [Merricks]
3. Truth / B. Truthmakers / 5. What Makes Truths / c. States of affairs make truths
Truthmaker demands not just a predication, but an existing state of affairs with essential ingredients [Merricks]
3. Truth / B. Truthmakers / 5. What Makes Truths / d. Being makes truths
If 'truth supervenes on being', worlds with the same entities, properties and relations have the same truths [Merricks]
If truth supervenes on being, that won't explain why truth depends on being [Merricks]
3. Truth / B. Truthmakers / 6. Making Negative Truths
It is implausible that claims about non-existence are about existing things [Merricks]
3. Truth / B. Truthmakers / 11. Truthmaking and Correspondence
Truthmaker isn't the correspondence theory, because it offers no analysis of truth [Merricks]
3. Truth / B. Truthmakers / 12. Rejecting Truthmakers
Speculations about non-existent things are not about existent things, so Truthmaker is false [Merricks]
I am a truthmaker for 'that a human exists', but is it about me? [Merricks]
3. Truth / C. Correspondence Truth / 3. Correspondence Truth critique
Being true is not a relation, it is a primitive monadic property [Merricks]
If the correspondence theory is right, then necessary truths must correspond to something [Merricks]
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
Deflationism just says there is no property of being truth [Merricks]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
A 'tautology' must include connectives [Wolf,RS]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
Deduction Theorem: T∪{P}|-Q, then T|-(P→Q), which justifies Conditional Proof [Wolf,RS]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / d. Universal quantifier ∀
Universal Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [Wolf,RS]
Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / e. Existential quantifier ∃
Existential Generalization (or 'proof by example'): if we can say P(t), then we can say something is P [Wolf,RS]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / e. Axiom of the Empty Set IV
Empty Set: ∃x∀y ¬(y∈x). The unique empty set exists [Wolf,RS]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / n. Axiom of Comprehension
Comprehension Axiom: if a collection is clearly specified, it is a set [Wolf,RS]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
In first-order logic syntactic and semantic consequence (|- and |=) nicely coincide [Wolf,RS]
First-order logic is weakly complete (valid sentences are provable); we can't prove every sentence or its negation [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory reveals the structures of mathematics [Wolf,RS]
Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS]
Model theory uses sets to show that mathematical deduction fits mathematical truth [Wolf,RS]
First-order model theory rests on completeness, compactness, and the Löwenheim-Skolem-Tarski theorem [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
An 'isomorphism' is a bijection that preserves all structural components [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The LST Theorem is a serious limitation of first-order logic [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 4. Completeness
If a theory is complete, only a more powerful language can strengthen it [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 10. Monotonicity
Most deductive logic (unlike ordinary reasoning) is 'monotonic' - we don't retract after new givens [Wolf,RS]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
An ordinal is an equivalence class of well-orderings, or a transitive set whose members are transitive [Wolf,RS]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Modern mathematics has unified all of its objects within set theory [Wolf,RS]
7. Existence / A. Nature of Existence / 3. Being / d. Non-being
The totality state is the most plausible truthmaker for negative existential truths [Merricks]
8. Modes of Existence / B. Properties / 3. Types of Properties
Some properties seem to be primitive, but others can be analysed [Merricks]
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / c. Dispositions as conditional
An object can have a disposition when the revelant conditional is false [Merricks]
9. Objects / A. Existence of Objects / 4. Impossible objects
Fregeans say 'hobbits do not exist' is just 'being a hobbit' is not exemplified [Merricks]
9. Objects / E. Objects over Time / 5. Temporal Parts
You believe you existed last year, but your segment doesn't, so they have different beliefs [Merricks]
10. Modality / B. Possibility / 9. Counterfactuals
Counterfactuals aren't about actuality, so they lack truthmakers or a supervenience base [Merricks]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
If 'Fido is possibly black' depends on Fido's counterparts, then it has no actual truthmaker [Merricks]
22. Metaethics / C. The Good / 3. Pleasure / a. Nature of pleasure
Intelligent pleasure is the perception of beauty, order and perfection [Leibniz]
27. Natural Reality / D. Time / 1. Nature of Time / h. Presentism
Presentists say that things have existed and will exist, not that they are instantaneous [Merricks]
Presentist should deny there is a present time, and just say that things 'exist' [Merricks]
Maybe only presentism allows change, by now having a property, and then lacking it [Merricks]
27. Natural Reality / D. Time / 2. Passage of Time / k. Temporal truths
How can a presentist explain an object's having existed? [Merricks]
28. God / A. Divine Nature / 3. Divine Perfections
Perfection is simply quantity of reality [Leibniz]
29. Religion / D. Religious Issues / 3. Problem of Evil / b. Human Evil
Evil serves a greater good, and pain is necessary for higher pleasure [Leibniz]