Combining Texts

All the ideas for 'fragments/reports', 'First-order Logic, 2nd-order, Completeness' and 'Short History of Modern Philosophy'

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19 ideas

1. Philosophy / B. History of Ideas / 2. Ancient Thought
1597 Thales was the first western thinker to believe the arché was intelligible [Roochnik on Thales]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
5637 Nowadays logic is seen as the science of extensions, not intensions [Scruton]
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]
10. Modality / C. Sources of Modality / 5. Modality from Actuality
3013 Nothing is stronger than necessity, which rules everything [Thales, by Diog. Laertius]
18. Thought / C. Content / 2. Ideas
5636 Cartesian 'ideas' confuse concepts and propositions [Scruton]
24. Political Theory / A. Basis of a State / 3. Natural Values / c. Natural rights
5660 Allegiance is prior to the recognition of individual rights [Scruton]
25. Social Practice / C. Rights / 1. Basis of Rights
5653 A right is a power which is enforced in the name of justice [Scruton]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / c. Ultimate substances
1494 Thales said water is the first principle, perhaps from observing that food is moist [Thales, by Aristotle]
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
1713 Thales must have thought soul causes movement, since he thought magnets have soul [Thales, by Aristotle]
29. Religion / A. Polytheistic Religion / 2. Greek Polytheism
1742 Thales said the gods know our wrong thoughts as well as our evil actions [Thales, by Diog. Laertius]