Combining Texts

All the ideas for 'A Pragmatic Conception of the A Priori', 'Absolute Necessities' and 'First-order Logic, 2nd-order, Completeness'

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25 ideas

5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
9358 There are several logics, none of which will ever derive falsehoods from truth [Lewis,CI]
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 / D. Assumptions for Logic / 2. Excluded Middle
9357 Excluded middle is just our preference for a simplified dichotomy in experience [Lewis,CI]
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 / F. Referring in Logic / 1. Naming / a. Names
9364 Names represent a uniformity in experience, or they name nothing [Lewis,CI]
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]
10. Modality / A. Necessity / 2. Nature of Necessity
15086 Absolute necessity might be achievable either logically or metaphysically [Hale]
10. Modality / A. Necessity / 3. Types of Necessity
8261 Maybe not-p is logically possible, but p is metaphysically necessary, so the latter is not absolute [Hale]
15081 A strong necessity entails a weaker one, but not conversely; possibilities go the other way [Hale]
15080 'Relative' necessity is just a logical consequence of some statements ('strong' if they are all true) [Hale]
10. Modality / A. Necessity / 5. Metaphysical Necessity
15082 Metaphysical necessity says there is no possibility of falsehood [Hale]
10. Modality / A. Necessity / 6. Logical Necessity
15085 'Broadly' logical necessities are derived (in a structure) entirely from the concepts [Hale]
15088 Logical necessities are true in virtue of the nature of all logical concepts [Hale]
10. Modality / A. Necessity / 11. Denial of Necessity
9362 Necessary truths are those we will maintain no matter what [Lewis,CI]
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
15087 Conceptual necessities are made true by all concepts [Hale]
12. Knowledge Sources / A. A Priori Knowledge / 7. A Priori from Convention
9365 We can maintain a priori principles come what may, but we can also change them [Lewis,CI]
18. Thought / E. Abstraction / 2. Abstracta by Selection
9361 We have to separate the mathematical from physical phenomena by abstraction [Lewis,CI]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / a. Scientific essentialism
9363 Science seeks classification which will discover laws, essences, and predictions [Lewis,CI]