Combining Texts

All the ideas for 'Abstract Objects: a Case Study', 'Intro to 'Modality and Tense'' and 'First-order Logic, 2nd-order, Completeness'

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

23 ideas

1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
9208 Philosophers with a new concept are like children with a new toy [Fine,K]
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 / 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]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
10580 Mathematics is both necessary and a priori because it really consists of logical truths [Yablo]
6. Mathematics / C. Sources of Mathematics / 9. Fictional Mathematics
10579 Putting numbers in quantifiable position (rather than many quantifiers) makes expression easier [Yablo]
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
10577 Concrete objects have few essential properties, but properties of abstractions are mostly essential [Yablo]
9210 Possible objects are abstract; actual concrete objects are possible; so abstract/concrete are compatible [Fine,K]
10578 We are thought to know concreta a posteriori, and many abstracta a priori [Yablo]
7. Existence / D. Theories of Reality / 3. Reality
9211 A non-standard realism, with no privileged standpoint, might challenge its absoluteness or coherence [Fine,K]
9. Objects / A. Existence of Objects / 3. Objects in Thought
9202 Objects, as well as sentences, can have logical form [Fine,K]
9. Objects / D. Essence of Objects / 7. Essence and Necessity / b. Essence not necessities
9206 We must distinguish between the identity or essence of an object, and its necessary features [Fine,K]
10. Modality / A. Necessity / 3. Types of Necessity
9205 The three basic types of necessity are metaphysical, natural and normative [Fine,K]
10. Modality / A. Necessity / 5. Metaphysical Necessity
9209 Metaphysical necessity may be 'whatever the circumstance', or 'regardless of circumstances' [Fine,K]
10. Modality / A. Necessity / 11. Denial of Necessity
9200 Empiricists suspect modal notions: either it happens or it doesn't; it is just regularities. [Fine,K]
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
9207 If sentence content is all worlds where it is true, all necessary truths have the same content! [Fine,K]