Combining Texts

All the ideas for 'fragments/reports', 'Logical Necessity' and 'Short History of Modern Philosophy'

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18 ideas

2. Reason / C. Styles of Reason / 1. Dialectic
Like spiderswebs, dialectical arguments are clever but useless [Ariston, by Diog. Laertius]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
The logic of metaphysical necessity is S5 [Rumfitt]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
Nowadays logic is seen as the science of extensions, not intensions [Scruton]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Soundness in argument varies with context, and may be achieved very informally indeed [Rumfitt]
There is a modal element in consequence, in assessing reasoning from suppositions [Rumfitt]
We reject deductions by bad consequence, so logical consequence can't be deduction [Rumfitt]
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
Contradictions include 'This is red and not coloured', as well as the formal 'B and not-B' [Rumfitt]
5. Theory of Logic / H. Proof Systems / 2. Axiomatic Proof
Geometrical axioms in logic are nowadays replaced by inference rules (which imply the logical truths) [Rumfitt]
10. Modality / A. Necessity / 3. Types of Necessity
A distinctive type of necessity is found in logical consequence [Rumfitt, by Hale/Hoffmann,A]
10. Modality / A. Necessity / 6. Logical Necessity
Logical necessity is when 'necessarily A' implies 'not-A is contradictory' [Rumfitt]
A logically necessary statement need not be a priori, as it could be unknowable [Rumfitt]
Narrow non-modal logical necessity may be metaphysical, but real logical necessity is not [Rumfitt]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
If a world is a fully determinate way things could have been, can anyone consider such a thing? [Rumfitt]
18. Thought / C. Content / 2. Ideas
Cartesian 'ideas' confuse concepts and propositions [Scruton]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / f. The Mean
The chief good is indifference to what lies midway between virtue and vice [Ariston, by Diog. Laertius]
23. Ethics / D. Deontological Ethics / 1. Deontology
Ariston says rules are useless for the virtuous and the non-virtuous [Ariston, by Annas]
24. Political Theory / A. Basis of a State / 3. Natural Values / c. Natural rights
Allegiance is prior to the recognition of individual rights [Scruton]
25. Social Practice / C. Rights / 1. Basis of Rights
A right is a power which is enforced in the name of justice [Scruton]