Combining Texts

All the ideas for 'fragments/reports', 'Introduction to the Philosophy of Mathematics' and 'Four Dimensionalism'

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52 ideas

1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
Metaphysical enquiry can survive if its conclusions are tentative [Sider]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Rejecting double negation elimination undermines reductio proofs [Colyvan]
Showing a disproof is impossible is not a proof, so don't eliminate double negation [Colyvan]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim proved his result for a first-order sentence, and Skolem generalised it [Colyvan]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Axioms are 'categorical' if all of their models are isomorphic [Colyvan]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinal numbers represent order relations [Colyvan]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Intuitionists only accept a few safe infinities [Colyvan]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / j. Infinite divisibility
Infinitesimals were sometimes zero, and sometimes close to zero [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Reducing real numbers to rationals suggested arithmetic as the foundation of maths [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Transfinite induction moves from all cases, up to the limit ordinal [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Most mathematical proofs are using set theory, but without saying so [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Structuralism say only 'up to isomorphism' matters because that is all there is to it [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
If 'in re' structures relies on the world, does the world contain rich enough structures? [Colyvan]
7. Existence / B. Change in Existence / 2. Processes
Four-dimensionalism sees things and processes as belonging in the same category [Sider]
8. Modes of Existence / B. Properties / 6. Categorical Properties
Proper ontology should only use categorical (actual) properties, not hypothetical ones [Sider]
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
If sortal terms fix the kind and the persistence conditions, we need to know what kinds there are [Sider]
9. Objects / B. Unity of Objects / 3. Unity Problems / b. Cat and its tail
If Tib is all of Tibbles bar her tail, when Tibbles loses her tail, two different things become one [Sider]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
Artists 'create' statues because they are essentially statues, and so lack identity with the lump of clay [Sider]
9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects
The stage view of objects is best for dealing with coincident entities [Sider]
9. Objects / C. Structure of Objects / 5. Composition of an Object
'Composition as identity' says that an object just is the objects which compose it [Sider]
9. Objects / D. Essence of Objects / 12. Essential Parts
Mereological essentialism says an object's parts are necessary for its existence [Sider]
9. Objects / E. Objects over Time / 3. Three-Dimensionalism
Three-dimensionalists assert 'enduring', being wholly present at each moment, and deny 'temporal parts' [Sider]
Some might say that its inconsistency with time travel is a reason to favour three-dimensionalism [Sider]
9. Objects / E. Objects over Time / 4. Four-Dimensionalism
Four-dimensionalists assert 'temporal parts', 'perduring', and being spread out over time [Sider]
4D says intrinsic change is difference between successive parts [Sider]
4D says each spatiotemporal object must have a temporal part at every moment at which it exists [Sider]
9. Objects / E. Objects over Time / 5. Temporal Parts
Temporal parts exist, but are not prior building blocks for objects [Sider]
Temporal parts are instantaneous [Sider]
How can an instantaneous stage believe anything, if beliefs take time? [Sider]
Four-dimensionalism says temporal parts are caused (through laws of motion) by previous temporal parts [Sider]
9. Objects / E. Objects over Time / 9. Ship of Theseus
The ship undergoes 'asymmetric' fission, where one candidate is seen as stronger [Sider]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
If you say Leibniz's Law doesn't apply to 'timebound' properties, you are no longer discussing identity [Sider]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Counterparts rest on similarity, so there are many such relations in different contexts [Sider]
14. Science / C. Induction / 6. Bayes's Theorem
Probability supports Bayesianism better as degrees of belief than as ratios of frequencies [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
Mathematics can reveal structural similarities in diverse systems [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / f. Necessity in explanations
Mathematics can show why some surprising events have to occur [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / m. Explanation by proof
Proof by cases (by 'exhaustion') is said to be unexplanatory [Colyvan]
Reductio proofs do not seem to be very explanatory [Colyvan]
If inductive proofs hold because of the structure of natural numbers, they may explain theorems [Colyvan]
Can a proof that no one understands (of the four-colour theorem) really be a proof? [Colyvan]
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
Mathematical generalisation is by extending a system, or by abstracting away from it [Colyvan]
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
Maybe motion is a dynamical quantity intrinsic to a thing at a particular time [Sider]
27. Natural Reality / C. Space / 6. Space-Time
Space is 3D and lacks a direction; time seems connected to causation [Sider]
27. Natural Reality / D. Time / 1. Nature of Time / g. Growing block
Between presentism and eternalism is the 'growing block' view - the past is real, the future is not [Sider]
27. Natural Reality / D. Time / 1. Nature of Time / h. Presentism
For Presentists there must always be a temporal vantage point for any description [Sider]
Presentists must deny truths about multiple times [Sider]
27. Natural Reality / D. Time / 2. Passage of Time / c. Tenses and time
Talk using tenses can be eliminated, by reducing it to indexical connections for an utterance [Sider]
27. Natural Reality / D. Time / 2. Passage of Time / f. Tenseless (B) series
The B-theory is adequate, except that it omits to say which time is present [Sider]
The B-series involves eternalism, and the reduction of tense [Sider]
27. Natural Reality / G. Biology / 3. Evolution
Archelaus said life began in a primeval slime [Archelaus, by Schofield]