Combining Texts

All the ideas for 'works', 'New Foundations for Mathematical Logic' and 'Introduction to 'Properties''

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6 ideas

2. Reason / B. Laws of Thought / 6. Ockham's Razor
Ockham's Razor is the principle that we need reasons to believe in entities [Mellor/Oliver]
     Full Idea: Ockham's Razor is the principle that we need reasons to believe in entities.
     From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §9)
     A reaction: This presumably follows from an assumption that all beliefs need reasons, but is that the case? The Principle of Sufficient Reason precedes Ockham's Razor.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
NF has no models, but just blocks the comprehension axiom, to avoid contradictions [Quine, by Dummett]
     Full Idea: Quine's New Foundations system of set theory, devised with no model in mind, but on the basis of a hunch that a purely formal restriction on the comprehension axiom would block all contradictions.
     From: report of Willard Quine (New Foundations for Mathematical Logic [1937]) by Michael Dummett - Frege philosophy of mathematics Ch.18
     A reaction: The point is that Quine (who had an ontological preference for 'desert landscapes') attempted to do without an ontological commitment to objects (and their subsequent models), with a purely formal system. Quine's NF is not now highly regarded.
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
Contradiction is not a sign of falsity, nor lack of contradiction a sign of truth [Pascal]
     Full Idea: Contradiction is not a sign of falsity, nor the lack of contradiction a sign of truth.
     From: Blaise Pascal (works [1660]), quoted by A.George / D.J.Velleman - Philosophies of Mathematics Ch.6
     A reaction: [Quoted in Auden and Kronenberger's Book of Aphorisms] Presumably we would now say that contradiction is a purely formal, syntactic notion, and not a semantic one. If you hit a contradiction, something has certainly gone wrong.
8. Modes of Existence / B. Properties / 6. Categorical Properties
Properties are respects in which particular objects may be alike or differ [Mellor/Oliver]
     Full Idea: Properties are respects in which particular objects may be alike or differ.
     From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §1)
     A reaction: Note that this definition does not mention a causal role for properties.
8. Modes of Existence / B. Properties / 12. Denial of Properties
Nominalists ask why we should postulate properties at all [Mellor/Oliver]
     Full Idea: Nominalists ask why we should postulate properties at all.
     From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §3)
     A reaction: Objects might be grasped without language, but events cannot be understood, and explanations of events seem inconceivable without properties (implying that they are essentially causal).
18. Thought / E. Abstraction / 5. Abstracta by Negation
Abstractions lack causes, effects and spatio-temporal locations [Mellor/Oliver]
     Full Idea: Abstract entities (such as sets) are usually understood as lacking causes, effects, and spatio-temporal location.
     From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §10)
     A reaction: This seems to beg some questions. Has the ideal of 'honour' never caused anything? Young men dream of pure velocity.