Combining Philosophers

Ideas for Roger Penrose, Chris Swoyer and Hugh MacColl

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

display all the ideas for this combination of philosophers

---

2 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set

21548	The null class is the class with all the non-existents as its members [MacColl, by Lackey]
	Full Idea: In 1905 the Scottish logician Hugh MacColl published a paper in which he argued that the null class in logic should be taken as the class with all the non-existents as its members.
	From: report of Hugh MacColl (Symbolic Reasoning [1905]) by Douglas Lackey - Intros to Russell's 'Essays in Analysis' p.95
	A reaction: For the null object (zero) Frege just chose one sample concept with an empty extension. MacColl's set seems to have a lot of members, given that it is 'null'. How many, I wonder? Russell responded to this paper.

4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets

10405	In the iterative conception of sets, they form a natural hierarchy [Swoyer]
	Full Idea: In the iterative conception of sets, they form a natural hierarchy.
	From: Chris Swoyer (Properties [2000], 4.1)