Combining Texts

Ideas for 'Logical Consequence', 'Travels in Four Dimensions' and 'Letter to Weber'

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

display all the ideas for this combination of texts

---

2 ideas

6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts

18244	I say the irrational is not the cut itself, but a new creation which corresponds to the cut [Dedekind]
	Full Idea: Of my theory of irrationals you say that the irrational number is nothing else than the cut itself, whereas I prefer to create something new (different from the cut), which corresponds to the cut. We have the right to claim such a creative power.
	From: Richard Dedekind (Letter to Weber [1888], 1888 Jan), quoted by Stewart Shapiro - Philosophy of Mathematics 5.4
	A reaction: Clearly a cut will not locate a unique irrational number, so something more needs to be done. Shapiro remarks here that for Dedekind numbers are objects.

6. Mathematics / B. Foundations for Mathematics / 2. Proof in Mathematics

10692	Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall]
	Full Idea: There are many proof-systems, the main being Hilbert proofs (with simple rules and complex axioms), or natural deduction systems (with few axioms and many rules, and the rules constitute the meaning of the connectives).
	From: JC Beall / G Restall (Logical Consequence [2005], 3)