Combining Texts

All the ideas for '67: Platonic Questions', 'Letters to Foucher' and 'Elements of Intuitionism (2nd ed)'

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4 ideas

4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Mathematical statements and entities that result from an infinite process must lack a truth-value [Dummett]
     Full Idea: On an intuitionistic view, neither the truth-value of a statement nor any other mathematical entity can be given as the final result of an infinite process, since an infinite process is precisely one that does not have a final result.
     From: Michael Dummett (Elements of Intuitionism (2nd ed) [2000], p.41), quoted by Ian Rumfitt - The Boundary Stones of Thought 7.3
     A reaction: This is rather a persuasive reason to sympathise with intuitionism. Mathematical tricks about 'limits' have lured us into believing in completed infinities, but actually that idea is incoherent.
8. Modes of Existence / C. Powers and Dispositions / 4. Powers as Essence
Essence is primitive force, or a law of change [Leibniz]
     Full Idea: The essence of substances consists in the primitive force of action, or the law of the sequence of changes.
     From: Gottfried Leibniz (Letters to Foucher [1675], 1676)
     A reaction: [a 1676 note on Foucher's reply] It take these to be the two key distinctive Leibnizian contributions to the sort of metaphysic that is needed by modern science. Nature works with intrinsic essences, which are forces determining action.
15. Nature of Minds / A. Nature of Mind / 2. Psuche
When the soul is intelligent and harmonious, it is part of god and derives from god [Plutarch]
     Full Idea: The soul, when it has partaken of intelligence and reason and concord, is not merely a work but also a part of god and has come to be not by his agency but both from him as source and out of his substance.
     From: Plutarch (67: Platonic Questions [c.85], II.1001)
     A reaction: A most intriguing shift of view from earlier concepts of the psuché. How did this come about? This man is a pagan. The history is in the evolution of Platonism. See 'The Middle Platonists' by John Dillon. Davidson is also very impressed by reason.
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
The connection in events enables us to successfully predict the future, so there must be a constant cause [Leibniz]
     Full Idea: There is a connection among our appearances that provides us the means to predict future appearances with success, and this connection must have a constant cause.
     From: Gottfried Leibniz (Letters to Foucher [1675])