Combining Texts

All the ideas for 'A Priori', 'Parts of Classes' and 'A Theory of Conditionals'

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50 ideas

1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
After 1903, Husserl avoids metaphysical commitments [Mares]
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
If we don't understand the singleton, then we don't understand classes [Lewis]
We can replace the membership relation with the member-singleton relation (plus mereology) [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
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]
Set theory isn't innocent; it generates infinities from a single thing; but mathematics needs it [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 / 4. Axioms for Number / a. Axioms for numbers
The truth of the axioms doesn't matter for pure mathematics, but it does for applied [Mares]
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]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
Mathematics is relations between properties we abstract from experience [Mares]
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]
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 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]
Lewis prefers giving up singletons to giving up sums [Lewis, by Fine,K]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
In nearby worlds where A is true, 'if A,B' is true or false if B is true or false [Stalnaker]
10. Modality / D. Knowledge of Modality / 2. A Priori Contingent
Light in straight lines is contingent a priori; stipulated as straight, because they happen to be so [Mares]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
A possible world is the ontological analogue of hypothetical beliefs [Stalnaker]
12. Knowledge Sources / A. A Priori Knowledge / 6. A Priori from Reason
Aristotelians dislike the idea of a priori judgements from pure reason [Mares]
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]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Empiricists say rationalists mistake imaginative powers for modal insights [Mares]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
The most popular view is that coherent beliefs explain one another [Mares]
14. Science / B. Scientific Theories / 3. Instrumentalism
Operationalism defines concepts by our ways of measuring them [Mares]
18. Thought / D. Concepts / 2. Origin of Concepts / b. Empirical concepts
Aristotelian justification uses concepts abstracted from experience [Mares]
18. Thought / D. Concepts / 4. Structure of Concepts / c. Classical concepts
The essence of a concept is either its definition or its conceptual relations? [Mares]
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
Possible worlds semantics has a nice compositional account of modal statements [Mares]
19. Language / D. Propositions / 3. Concrete Propositions
Unstructured propositions are sets of possible worlds; structured ones have components [Mares]
27. Natural Reality / C. Space / 3. Points in Space
Maybe space has points, but processes always need regions with a size [Mares]