Combining Texts

All the ideas for 'First-order Logic, 2nd-order, Completeness', 'Does Moral Subjectivism Rest on a Mistake?' and 'On the Essence of Truth'

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

---

14 ideas

3. Truth / A. Truth Problems / 1. Truth

21953

For Heidegger there is 'ontic' truth or 'uncoveredness', as in "he is a true friend" [Heidegger, by Wrathall]

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]

22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / f. Ethical non-cognitivism

22485

Non-cognitivists give the conditions of use of moral sentences as facts about the speaker [Foot]

22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism

22486

The mistake is to think good grounds aren't enough for moral judgement, which also needs feelings [Foot]

22. Metaethics / B. Value / 1. Nature of Value / b. Fact and value

22487

Moral arguments are grounded in human facts [Foot]