Combining Texts

All the ideas for 'Aristotle and Descartes on Matter', 'Does Conceivability Entail Possibility?' and 'Symbolic Reasoning'

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4 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
21548 The null class is the class with all the non-existents as its members [MacColl, by Lackey]
     Full Idea: In 1905 the Scottish logician Hugh MacColl published a paper in which he argued that the null class in logic should be taken as the class with all the non-existents as its members.
     From: report of Hugh MacColl (Symbolic Reasoning [1905]) by Douglas Lackey - Intros to Russell's 'Essays in Analysis' p.95
     A reaction: For the null object (zero) Frege just chose one sample concept with an empty extension. MacColl's set seems to have a lot of members, given that it is 'null'. How many, I wonder? Russell responded to this paper.
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
16473 Modal Rationalism: conceivability gives a priori access to modal truths [Chalmers, by Stalnaker]
     Full Idea: Chalmers' 'modal rationalist' is one who identifies what is possible with what is conceivable; the central claim of the doctrine is that we have a priori access to modal truth.
     From: report of David J.Chalmers (Does Conceivability Entail Possibility? [2002]) by Robert C. Stalnaker - Mere Possibilities 5
     A reaction: A helpful clarification, as I can now see how hopelessly and utterly wrong Chalmers is (about almost everything), and I find my confidence in any sort of genuine a priori knowledge (except of conceptual relations) dwindling by the minute.
19258 Evaluate primary possibility from some world, and secondary possibility from this world [Chalmers, by Vaidya]
     Full Idea: For Chalmers, that water is XYZ is 'primary possible' (a priori, or conceptually), because it is true in some world considered as actual. It is 'secondary impossible', when it is evaluated from the Earth as actual.
     From: report of David J.Chalmers (Does Conceivability Entail Possibility? [2002]) by Anand Vaidya - Understanding and Essence Intro
     A reaction: [compressed] This is Chalmers' account of how we can know possibility from conceivability, via his two-dimensional semantics (see alphabetical themes).
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / b. Prime matter
19399 Prime matter is nothing when it is at rest [Leibniz]
     Full Idea: Primary matter is nothing if considered at rest.
     From: Gottfried Leibniz (Aristotle and Descartes on Matter [1671], p.90)
     A reaction: This goes with Leibniz's Idea 13393, that activity is the hallmark of existence. No one seems to have been able to make good sense of prime matter, and it plays little role in Aristotle's writings.