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All the ideas for '', 'First-order Logic, 2nd-order, Completeness' and 'Necessity and Non-Existence'

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30 ideas

3. Truth / B. Truthmakers / 5. What Makes Truths / a. What makes truths
15063 Some sentences depend for their truth on worldly circumstances, and others do not [Fine,K]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
11211 If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
10751 Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg]
10757 Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg]
10759 There are at least seven possible systems of semantics for second-order logic [Rossberg]
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
10753 Logical consequence is intuitively semantic, and captured by model theory [Rossberg]
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
10752 Γ |- S says S can be deduced from Γ; Γ |= S says a good model for Γ makes S true [Rossberg]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
10754 In proof-theory, logical form is shown by the logical constants [Rossberg]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
11212 The sense of a connective comes from primitively obvious rules of inference [Rumfitt]
11210 Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10756 A model is a domain, and an interpretation assigning objects, predicates, relations etc. [Rossberg]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
10758 If models of a mathematical theory are all isomorphic, it is 'categorical', with essentially one model [Rossberg]
5. Theory of Logic / K. Features of Logics / 4. Completeness
10761 Completeness can always be achieved by cunning model-design [Rossberg]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
10755 A deductive system is only incomplete with respect to a formal semantics [Rossberg]
7. Existence / A. Nature of Existence / 2. Types of Existence
15078 There are levels of existence, as well as reality; objects exist at the lowest level in which they can function [Fine,K]
7. Existence / D. Theories of Reality / 3. Reality
15072 Bottom level facts are subject to time and world, middle to world but not time, and top to neither [Fine,K]
7. Existence / D. Theories of Reality / 8. Facts / b. Types of fact
15071 Tensed and tenseless sentences state two sorts of fact, which belong to two different 'realms' of reality [Fine,K]
9. Objects / B. Unity of Objects / 1. Unifying an Object / a. Intrinsic unification
15075 Modal features are not part of entities, because they are accounted for by the entity [Fine,K]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
15065 What it is is fixed prior to existence or the object's worldly features [Fine,K]
9. Objects / D. Essence of Objects / 9. Essence and Properties
15076 Essential features of an object have no relation to how things actually are [Fine,K]
9. Objects / F. Identity among Objects / 5. Self-Identity
15073 Self-identity should have two components, its existence, and its neutral identity with itself [Fine,K]
9. Objects / F. Identity among Objects / 6. Identity between Objects
15074 We would understand identity between objects, even if their existence was impossible [Fine,K]
10. Modality / A. Necessity / 8. Transcendental Necessity
15064 Proper necessary truths hold whatever the circumstances; transcendent truths regardless of circumstances [Fine,K]
10. Modality / C. Sources of Modality / 6. Necessity from Essence
15070 It is the nature of Socrates to be a man, so necessarily he is a man [Fine,K]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
15069 Possible worlds may be more limited, to how things might actually turn out [Fine,K]
15068 The actual world is a totality of facts, so we also think of possible worlds as totalities [Fine,K]
19. Language / F. Communication / 3. Denial
11214 We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt]
27. Natural Reality / D. Time / 2. Passage of Time / c. Tenses and time
15077 It is said that in the A-theory, all existents and objects must be tensed, as well as the sentences [Fine,K]
15067 A-theorists tend to reject the tensed/tenseless distinction [Fine,K]
27. Natural Reality / D. Time / 2. Passage of Time / f. Tenseless (B) series
15066 B-theorists say tensed sentences have an unfilled argument-place for a time [Fine,K]