Combining Texts

All the ideas for 'Intro to G��del's Theorems', 'Outline of a System of the Philosophy of Nature' and 'Knowledge by Agreement'

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76 ideas

3. Truth / C. Correspondence Truth / 1. Correspondence Truth
Correspondence could be with other beliefs, rather than external facts [Kusch]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
Tarskians distinguish truth from falsehood by relations between members of sets [Kusch]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
There cannot be a set theory which is complete [Smith,P]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order arithmetic can prove new sentences of first-order [Smith,P]
5. Theory of Logic / E. Structures of Logic / 5. Functions in Logic
A 'partial function' maps only some elements to another set [Smith,P]
A 'total function' maps every element to one element in another set [Smith,P]
An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P]
The 'range' of a function is the set of elements in the output set created by the function [Smith,P]
Two functions are the same if they have the same extension [Smith,P]
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
The Comprehension Schema says there is a property only had by things satisfying a condition [Smith,P]
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
A 'theorem' of a theory is a sentence derived from the axioms using the proof system [Smith,P]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
A 'natural deduction system' has no axioms but many rules [Smith,P]
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
No nice theory can define truth for its own language [Smith,P]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
An 'injective' ('one-to-one') function creates a distinct output element from each original [Smith,P]
A 'surjective' ('onto') function creates every element of the output set [Smith,P]
A 'bijective' function has one-to-one correspondence in both directions [Smith,P]
5. Theory of Logic / K. Features of Logics / 3. Soundness
If everything that a theory proves is true, then it is 'sound' [Smith,P]
Soundness is true axioms and a truth-preserving proof system [Smith,P]
A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P]
5. Theory of Logic / K. Features of Logics / 4. Completeness
A theory is 'negation complete' if it proves all sentences or their negation [Smith,P]
'Complete' applies both to whole logics, and to theories within them [Smith,P]
A theory is 'negation complete' if one of its sentences or its negation can always be proved [Smith,P]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
Two routes to Incompleteness: semantics of sound/expressible, or syntax of consistency/proof [Smith,P]
5. Theory of Logic / K. Features of Logics / 7. Decidability
'Effective' means simple, unintuitive, independent, controlled, dumb, and terminating [Smith,P]
A theory is 'decidable' if all of its sentences could be mechanically proved [Smith,P]
Any consistent, axiomatized, negation-complete formal theory is decidable [Smith,P]
5. Theory of Logic / K. Features of Logics / 8. Enumerability
A set is 'enumerable' is all of its elements can result from a natural number function [Smith,P]
A set is 'effectively enumerable' if a computer could eventually list every member [Smith,P]
A finite set of finitely specifiable objects is always effectively enumerable (e.g. primes) [Smith,P]
The set of ordered pairs of natural numbers <i,j> is effectively enumerable [Smith,P]
The thorems of a nice arithmetic can be enumerated, but not the truths (so they're diffferent) [Smith,P]
5. Theory of Logic / K. Features of Logics / 9. Expressibility
Being 'expressible' depends on language; being 'capture/represented' depends on axioms and proof system [Smith,P]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
For primes we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))) [Smith,P]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
The reals contain the naturals, but the theory of reals doesn't contain the theory of naturals [Smith,P]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / f. Arithmetic
The truths of arithmetic are just true equations and their universally quantified versions [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
All numbers are related to zero by the ancestral of the successor relation [Smith,P]
The number of Fs is the 'successor' of the Gs if there is a single F that isn't G [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / b. Baby arithmetic
Baby arithmetic covers addition and multiplication, but no general facts about numbers [Smith,P]
Baby Arithmetic is complete, but not very expressive [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / c. Robinson arithmetic
Robinson Arithmetic (Q) is not negation complete [Smith,P]
Robinson Arithmetic 'Q' has basic axioms, quantifiers and first-order logic [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
Natural numbers have zero, unique successors, unending, no circling back, and no strays [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
The logic of arithmetic must quantify over properties of numbers to handle induction [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Multiplication only generates incompleteness if combined with addition and successor [Smith,P]
Incompleteness results in arithmetic from combining addition and successor with multiplication [Smith,P]
8. Modes of Existence / A. Relations / 4. Formal Relations / c. Ancestral relation
The 'ancestral' of a relation is a new relation which creates a long chain of the original relation [Smith,P]
11. Knowledge Aims / A. Knowledge / 4. Belief / a. Beliefs
We can have knowledge without belief, if others credit us with knowledge [Kusch]
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / d. Absolute idealism
For Schelling the Absolute spirit manifests as nature in which self-consciousness evolves [Schelling, by Lewis,PB]
Metaphysics aims at the Absolute, which goes beyond subjective and objective viewpoints [Schelling, by Pinkard]
11. Knowledge Aims / C. Knowing Reality / 4. Solipsism
Methodological Solipsism assumes all ideas could be derived from one mind [Kusch]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
Foundations seem utterly private, even from oneself at a later time [Kusch]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
Testimony is reliable if it coheres with evidence for a belief, and with other beliefs [Kusch]
The coherentist restricts the space of reasons to the realm of beliefs [Kusch]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / c. Coherentism critique
Individualistic coherentism lacks access to all of my beliefs, or critical judgement of my assessment [Kusch]
Individual coherentism cannot generate the necessary normativity [Kusch]
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
Cultures decide causal routes, and they can be critically assessed [Kusch]
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
Process reliabilism has been called 'virtue epistemology', resting on perception, memory, reason [Kusch]
13. Knowledge Criteria / C. External Justification / 6. Contextual Justification / a. Contextualism
Justification depends on the audience and one's social role [Kusch]
13. Knowledge Criteria / C. External Justification / 7. Testimony
Testimony is an area in which epistemology meets ethics [Kusch]
Powerless people are assumed to be unreliable, even about their own lives [Kusch]
Testimony does not just transmit knowledge between individuals - it actually generates knowledge [Kusch]
Some want to reduce testimony to foundations of perceptions, memories and inferences [Kusch]
Testimony won't reduce to perception, if perception depends on social concepts and categories [Kusch]
A foundation is what is intelligible, hence from a rational source, and tending towards truth [Kusch]
Vindicating testimony is an expression of individualism [Kusch]
13. Knowledge Criteria / C. External Justification / 8. Social Justification
Myths about lonely genius are based on epistemological individualism [Kusch]
Communitarian Epistemology says 'knowledge' is a social status granted to groups of people [Kusch]
Private justification is justification to imagined other people [Kusch]
16. Persons / E. Rejecting the Self / 2. Self as Social Construct
To be considered 'an individual' is performed by a society [Kusch]
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
Our experience may be conceptual, but surely not the world itself? [Kusch]
19. Language / F. Communication / 1. Rhetoric
Often socialising people is the only way to persuade them [Kusch]
24. Political Theory / D. Ideologies / 7. Communitarianism / a. Communitarianism
Communitarianism in epistemology sees the community as the primary knower [Kusch]
26. Natural Theory / A. Speculations on Nature / 1. Nature
Schelling sought a union between the productivities of nature and of the mind [Schelling, by Bowie]
Schelling made organisms central to nature, because mere mechanism could never produce them [Schelling, by Pinkard]
26. Natural Theory / B. Natural Kinds / 7. Critique of Kinds
Natural kinds are social institutions [Kusch]
28. God / A. Divine Nature / 4. Divine Contradictions
Omniscience is incoherent, since knowledge is a social concept [Kusch]