Combining Texts

Ideas for 'Introduction to Russell's Theory of Types', 'Logic (Port-Royal Art of Thinking)' and 'Mathematics without Foundations'

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

display all the ideas for this combination of texts


2 ideas

7. Existence / C. Structure of Existence / 7. Abstract/Concrete / b. Levels of abstraction
We can rise by degrees through abstraction, with higher levels representing more things [Arnauld,A/Nicole,P]
     Full Idea: I can start with a triangle, and rise by degrees to all straight-lined figures and to extension itself. The lower degree will include the higher degree. Since the higher degree is less determinate, it can represent more things.
     From: Arnauld / Nicole (Logic (Port-Royal Art of Thinking) [1662], I.5)
     A reaction: [compressed] This attempts to explain the generalising ability of abstraction cited in Idea 10501. If you take a complex object and eliminate features one by one, it can only 'represent' more particulars; it could hardly represent fewer.
7. Existence / D. Theories of Reality / 4. Anti-realism
You can't deny a hypothesis a truth-value simply because we may never know it! [Putnam]
     Full Idea: Surely the mere fact that we may never know whether the continuum hypothesis is true or false is by itself just no reason to think that it doesn't have a truth value!
     From: Hilary Putnam (Mathematics without Foundations [1967])
     A reaction: This is Putnam in 1967. Things changed later. Personally I am with the younger man all they way, but I reserve the right to totally change my mind.