Combining Texts

All the ideas for 'Particulars in Particular Clothing', 'Parts of Classes' and 'Letters to Schlick'

expand these ideas     |    start again     |     specify just one area for these texts


37 ideas

4. Formal Logic / F. Set Theory ST / 1. Set Theory
Sets are mereological sums of the singletons of their members [Lewis, by Armstrong]
We can build set theory on singletons: classes are then fusions of subclasses, membership is the singleton [Lewis]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
Classes divide into subclasses in many ways, but into members in only one way [Lewis]
A subclass of a subclass is itself a subclass; a member of a member is not in general a member [Lewis]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
We needn't accept this speck of nothingness, this black hole in the fabric of Reality! [Lewis]
We can accept the null set, but there is no null class of anything [Lewis]
There are four main reasons for asserting that there is an empty set [Lewis]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
We can replace the membership relation with the member-singleton relation (plus mereology) [Lewis]
If we don't understand the singleton, then we don't understand classes [Lewis]
If singleton membership is external, why is an object a member of one rather than another? [Lewis]
Maybe singletons have a structure, of a thing and a lasso? [Lewis]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Set theory has some unofficial axioms, generalisations about how to understand it [Lewis]
Set theory reduces to a mereological theory with singletons as the only atoms [Lewis, by MacBride]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / a. Sets as existing
Set theory isn't innocent; it generates infinities from a single thing; but mathematics needs it [Lewis]
If singletons are where their members are, then so are all sets [Lewis]
A huge part of Reality is only accepted as existing if you have accepted set theory [Lewis]
5. Theory of Logic / G. Quantification / 6. Plural Quantification
Plural quantification lacks a complete axiom system [Lewis]
I like plural quantification, but am not convinced of its connection with second-order logic [Lewis]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / f. Zermelo numbers
Zermelo's model of arithmetic is distinctive because it rests on a primitive of set theory [Lewis]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Giving up classes means giving up successful mathematics because of dubious philosophy [Lewis]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
To be a structuralist, you quantify over relations [Lewis]
7. Existence / A. Nature of Existence / 2. Types of Existence
Existence doesn't come in degrees; once asserted, it can't then be qualified [Lewis]
7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff
We have no idea of a third sort of thing, that isn't an individual, a class, or their mixture [Lewis]
Atomless gunk is an individual whose parts all have further proper parts [Lewis]
8. Modes of Existence / B. Properties / 11. Properties as Sets
A property is any class of possibilia [Lewis]
8. Modes of Existence / B. Properties / 13. Tropes / a. Nature of tropes
Internal relations combine some tropes into a nucleus, which bears the non-essential tropes [Simons, by Edwards]
9. Objects / C. Structure of Objects / 5. Composition of an Object
The many are many and the one is one, so they can't be identical [Lewis]
Lewis affirms 'composition as identity' - that an object is no more than its parts [Lewis, by Merricks]
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
In mereology no two things consist of the same atoms [Lewis]
Trout-turkeys exist, despite lacking cohesion, natural joints and united causal power [Lewis]
Given cats, a fusion of cats adds nothing further to reality [Lewis]
The one has different truths from the many; it is one rather than many, one rather than six [Lewis]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
Lewis prefers giving up singletons to giving up sums [Lewis, by Fine,K]
Lewis only uses fusions to create unities, but fusions notoriously flatten our distinctions [Oliver/Smiley on Lewis]
A commitment to cat-fusions is not a further commitment; it is them and they are it [Lewis]
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / a. Qualities in perception
Some say qualities are parts of things - as repeatable universals, or as particulars [Lewis]
19. Language / F. Communication / 6. Interpreting Language / a. Translation
All translation loses some content (but language does not create reality) [Carnap]