Combining Texts

All the ideas for 'Letters to Edward Stillingfleet', 'The Aim and Structure of Physical Theory' and 'Logical Necessity'

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15 ideas

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 / 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]
9. Objects / D. Essence of Objects / 3. Individual Essences
Every individual thing which exists has an essence, which is its internal constitution [Locke]
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]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
If it is knowledge, it is certain; if it isn't certain, it isn't knowledge [Locke]
14. Science / A. Basis of Science / 6. Falsification
Observation can force rejection of some part of the initial set of claims [Duhem, by Boulter]
14. Science / B. Scientific Theories / 6. Theory Holism
Experiments only test groups of hypotheses, and can't show which one is wrong [Duhem]