Combining Texts

All the ideas for 'Logical Necessity', 'What is the Source of Knowledge of Modal Truths?' and '26: Oracles in Decline'

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31 ideas

2. Reason / D. Definition / 6. Definition by Essence
A definition of a circle will show what it is, and show its generating principle [Lowe]
Defining an ellipse by conic sections reveals necessities, but not the essence of an ellipse [Lowe]
An essence is what an entity is, revealed by a real definition; this is not an entity in its own right [Lowe]
2. Reason / D. Definition / 11. Ostensive Definition
Simple things like 'red' can be given real ostensive definitions [Lowe]
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 / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
The essence of lumps and statues shows that two objects coincide but are numerically distinct [Lowe]
The essence of a bronze statue shows that it could be made of different bronze [Lowe]
9. Objects / D. Essence of Objects / 4. Essence as Definition
Grasping an essence is just grasping a real definition [Lowe]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
Explanation can't give an account of essence, because it is too multi-faceted [Lowe]
9. Objects / D. Essence of Objects / 14. Knowledge of Essences
If we must know some entity to know an essence, we lack a faculty to do that [Lowe]
10. Modality / A. Necessity / 3. Types of Necessity
Logical necessities, based on laws of logic, are a proper sub-class of metaphysical necessities [Lowe]
A distinctive type of necessity is found in logical consequence [Rumfitt, by Hale/Hoffmann,A]
10. Modality / A. Necessity / 5. Metaphysical Necessity
'Metaphysical' necessity is absolute and objective - the strongest kind of necessity [Lowe]
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 / B. Possibility / 2. Epistemic possibility
'Epistemic' necessity is better called 'certainty' [Lowe]
10. Modality / C. Sources of Modality / 6. Necessity from Essence
If an essence implies p, then p is an essential truth, and hence metaphysically necessary [Lowe]
Metaphysical necessity is either an essential truth, or rests on essential truths [Lowe]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
We could give up possible worlds if we based necessity on essences [Lowe]
If a world is a fully determinate way things could have been, can anyone consider such a thing? [Rumfitt]
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / a. Idealism
The sun is always bright; it doesn't become bright when it emerges [Plutarch]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
'Intuitions' are just unreliable 'hunches'; over centuries intuitions change enormously [Lowe]
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
A concept is a way of thinking of things or kinds, whether or not they exist [Lowe]
19. Language / B. Reference / 3. Direct Reference / a. Direct reference
Direct reference doesn't seem to require that thinkers know what it is they are thinking about [Lowe]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / e. Anti scientific essentialism
H2O isn't necessary, because different laws of nature might affect how O and H combine [Lowe]