Combining Texts

All the ideas for 'fragments/reports', 'Interview with Philippa Foot' and 'First-order Logic, 2nd-order, Completeness'

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20 ideas

5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
10757 Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg]
10751 Second-order logic needs the sets, and its consequence has epistemological problems [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]
9. Objects / C. Structure of Objects / 6. Constitution of an Object
6019 If someone squashed a horse to make a dog, something new would now exist [Mnesarchus]
18. Thought / A. Modes of Thought / 5. Rationality / b. Human rationality
23438 Full rationality must include morality [Foot]
20. Action / C. Motives for Action / 3. Acting on Reason / a. Practical reason
23437 Practical reason is goodness in choosing actions [Foot]
20. Action / C. Motives for Action / 3. Acting on Reason / c. Reasons as causes
23436 It is an odd Humean view to think a reason to act must always involve caring [Foot]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / d. Biological ethics
23431 Human defects are just like plant or animal defects [Foot]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / k. Ethics from nature
23433 Humans need courage like a plant needs roots [Foot]
23432 Concepts such as function, welfare, flourishing and interests only apply to living things [Foot]
22. Metaethics / B. Value / 1. Nature of Value / b. Fact and value
23434 There is no fact-value gap in 'owls should see in the dark' [Foot]
22. Metaethics / B. Value / 1. Nature of Value / f. Ultimate value
23439 Principles are not ultimate, but arise from the necessities of human life [Foot]
22. Metaethics / B. Value / 2. Values / a. Normativity
23435 If you demonstrate the reason to act, there is no further question of 'why should I?' [Foot]