Combining Texts

Ideas for 'Letters to Antoine Arnauld', 'Difficulties of Transfinite Numbers and Types' and 'Letter to G.H. Schaller'

unexpand these ideas     |    start again     |     choose another area for these texts

display all the ideas for this combination of texts


3 ideas

6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
It is possible that an omnipotent God might make one and two fail to equal three [Descartes]
     Full Idea: Since every basic truth depends on God's omnipotence, I would not dare to say that God cannot make it....that one and two should not be three.
     From: René Descartes (Letters to Antoine Arnauld [1645]), quoted by A.W. Moore - The Evolution of Modern Metaphysics 01.3
     A reaction: An unusual view. Most people would say that if Descartes can doubt something that simple, he should also doubt his reasons for believing in God's existence.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
We need rules for deciding which norms are predicative (unless none of them are) [Russell]
     Full Idea: We need rules for deciding what norms are predicative and what are not, unless we adopt the view (which has much to recommend it) that no norms are predicative. ...[146] A predative propositional function is one which determines a class.
     From: Bertrand Russell (Difficulties of Transfinite Numbers and Types [1905], p.141)
     A reaction: He is referring to his 'no class' theory, which he favoured at that time.
'Predicative' norms are those which define a class [Russell]
     Full Idea: Norms (containing one variable) which do not define classes I propose to call 'non-predicative'; those which do define classes I shall call 'predicative'.
     From: Bertrand Russell (Difficulties of Transfinite Numbers and Types [1905], p.141)