Combining Philosophers

All the ideas for Penelope Maddy, M.R. Ayers and J Pollock / J Cruz

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94 ideas

4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
'Forcing' can produce new models of ZFC from old models [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
A Large Cardinal Axiom would assert ever-increasing stages in the hierarchy [Maddy]
New axioms are being sought, to determine the size of the continuum [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / b. Axiom of Extensionality I
The Axiom of Extensionality seems to be analytic [Maddy]
Extensional sets are clearer, simpler, unique and expressive [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
The Axiom of Infinity states Cantor's breakthrough that launched modern mathematics [Maddy]
Infinite sets are essential for giving an account of the real numbers [Maddy]
Axiom of Infinity: completed infinite collections can be treated mathematically [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / g. Axiom of Powers VI
The Power Set Axiom is needed for, and supported by, accounts of the continuum [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / i. Axiom of Foundation VIII
The Axiom of Foundation says every set exists at a level in the set hierarchy [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
Efforts to prove the Axiom of Choice have failed [Maddy]
Modern views say the Choice set exists, even if it can't be constructed [Maddy]
A large array of theorems depend on the Axiom of Choice [Maddy]
The Axiom of Choice paradoxically allows decomposing a sphere into two identical spheres [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
Axiom of Reducibility: propositional functions are extensionally predicative [Maddy]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets
The Iterative Conception says everything appears at a stage, derived from the preceding appearances [Maddy]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / f. Limitation of Size
Limitation of Size is a vague intuition that over-large sets may generate paradoxes [Maddy]
4. Formal Logic / F. Set Theory ST / 7. Natural Sets
The master science is physical objects divided into sets [Maddy]
Maddy replaces pure sets with just objects and perceived sets of objects [Maddy, by Shapiro]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Henkin semantics is more plausible for plural logic than for second-order logic [Maddy]
5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
Critics of if-thenism say that not all starting points, even consistent ones, are worth studying [Maddy]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
'Propositional functions' are propositions with a variable as subject or predicate [Maddy]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Hilbert's geometry and Dedekind's real numbers were role models for axiomatization [Maddy]
If two mathematical themes coincide, that suggest a single deep truth [Maddy]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / d. Counting via concepts
Counting 'coin in this box' may have coin as the unit, with 'in this box' merely as the scope [Ayers]
If counting needs a sortal, what of things which fall under two sortals? [Ayers]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
Completed infinities resulted from giving foundations to calculus [Maddy]
Cantor and Dedekind brought completed infinities into mathematics [Maddy]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / g. Continuum Hypothesis
Every infinite set of reals is either countable or of the same size as the full set of reals [Maddy]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
Infinity has degrees, and large cardinals are the heart of set theory [Maddy]
For any cardinal there is always a larger one (so there is no set of all sets) [Maddy]
An 'inaccessible' cardinal cannot be reached by union sets or power sets [Maddy]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / l. Limits
Theorems about limits could only be proved once the real numbers were understood [Maddy]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / c. Fregean numbers
The extension of concepts is not important to me [Maddy]
In the ZFC hierarchy it is impossible to form Frege's set of all three-element sets [Maddy]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
Frege solves the Caesar problem by explicitly defining each number [Maddy]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Set theory (unlike the Peano postulates) can explain why multiplication is commutative [Maddy]
Standardly, numbers are said to be sets, which is neat ontology and epistemology [Maddy]
Numbers are properties of sets, just as lengths are properties of physical objects [Maddy]
A natural number is a property of sets [Maddy, by Oliver]
Making set theory foundational to mathematics leads to very fruitful axioms [Maddy]
Unified set theory gives a final court of appeal for mathematics [Maddy]
Set theory brings mathematics into one arena, where interrelations become clearer [Maddy]
Mathematics rests on the logic of proofs, and on the set theoretic axioms [Maddy]
Identifying geometric points with real numbers revealed the power of set theory [Maddy]
The line of rationals has gaps, but set theory provided an ordered continuum [Maddy]
Set-theory tracks the contours of mathematical depth and fruitfulness [Maddy]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / b. Mathematics is not set theory
Number theory doesn't 'reduce' to set theory, because sets have number properties [Maddy]
Sets exist where their elements are, but numbers are more like universals [Maddy]
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / b. Against mathematical platonism
If mathematical objects exist, how can we know them, and which objects are they? [Maddy]
6. Mathematics / C. Sources of Mathematics / 2. Intuition of Mathematics
Intuition doesn't support much mathematics, and we should question its reliability [Maddy, by Shapiro]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
We know mind-independent mathematical truths through sets, which rest on experience [Maddy, by Jenkins]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / b. Indispensability of mathematics
Scientists posit as few entities as possible, but set theorist posit as many as possible [Maddy]
Maybe applications of continuum mathematics are all idealisations [Maddy]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
The connection of arithmetic to perception has been idealised away in modern infinitary mathematics [Maddy]
6. Mathematics / C. Sources of Mathematics / 5. Numbers as Adjectival
Number words are unusual as adjectives; we don't say 'is five', and numbers always come first [Maddy]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
We can get arithmetic directly from HP; Law V was used to get HP from the definition of number [Maddy]
7. Existence / B. Change in Existence / 4. Events / a. Nature of events
Events do not have natural boundaries, and we have to set them [Ayers]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
The theoretical indispensability of atoms did not at first convince scientists that they were real [Maddy]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
To express borderline cases of objects, you need the concept of an 'object' [Ayers]
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
Speakers need the very general category of a thing, if they are to think about it [Ayers]
We use sortals to classify physical objects by the nature and origin of their unity [Ayers]
Seeing caterpillar and moth as the same needs continuity, not identity of sortal concepts [Ayers]
Recognising continuity is separate from sortals, and must precede their use [Ayers]
9. Objects / B. Unity of Objects / 1. Unifying an Object / a. Intrinsic unification
Could the same matter have more than one form or principle of unity? [Ayers]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
If there are two objects, then 'that marble, man-shaped object' is ambiguous [Ayers]
9. Objects / D. Essence of Objects / 5. Essence as Kind
Sortals basically apply to individuals [Ayers]
9. Objects / E. Objects over Time / 5. Temporal Parts
You can't have the concept of a 'stage' if you lack the concept of an object [Ayers]
Temporal 'parts' cannot be separated or rearranged [Ayers]
9. Objects / F. Identity among Objects / 1. Concept of Identity
Some say a 'covering concept' completes identity; others place the concept in the reference [Ayers]
9. Objects / F. Identity among Objects / 3. Relative Identity
If diachronic identities need covering concepts, why not synchronic identities too? [Ayers]
11. Knowledge Aims / A. Knowledge / 1. Knowledge
The main epistemological theories are foundationalist, coherence, probabilistic and reliabilist [Pollock/Cruz]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
Most people now agree that our reasoning proceeds defeasibly, rather than deductively [Pollock/Cruz]
To believe maximum truths, believe everything; to have infallible beliefs, believe nothing [Pollock/Cruz]
11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / b. Direct realism
Direct realism says justification is partly a function of pure perceptual states, not of beliefs [Pollock/Cruz]
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
Phenomenalism offered conclusive perceptual knowledge, but conclusive reasons no longer seem essential [Pollock/Cruz]
12. Knowledge Sources / B. Perception / 1. Perception
Perception causes beliefs in us, without inference or justification [Pollock/Cruz]
12. Knowledge Sources / B. Perception / 6. Inference in Perception
Sense evidence is not beliefs, because they are about objective properties, not about appearances [Pollock/Cruz]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / a. Justification issues
Bayesian epistemology is Bayes' Theorem plus the 'simple rule' (believe P if it is probable) [Pollock/Cruz]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / a. Pro-internalism
Internalism says if anything external varies, the justifiability of the belief does not vary [Pollock/Cruz]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
People rarely have any basic beliefs, and never enough for good foundations [Pollock/Cruz]
Foundationalism requires self-justification, not incorrigibility [Pollock/Cruz]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / d. Rational foundations
Reason cannot be an ultimate foundation, because rational justification requires prior beliefs [Pollock/Cruz]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
Foundationalism is wrong, because either all beliefs are prima facie justified, or none are [Pollock/Cruz]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
Negative coherence theories do not require reasons, so have no regress problem [Pollock/Cruz]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / c. Coherentism critique
Coherence theories fail, because they can't accommodate perception as the basis of knowledge [Pollock/Cruz]
Coherence theories isolate justification from the world [Pollock/Cruz]
13. Knowledge Criteria / C. External Justification / 1. External Justification
Externalism comes as 'probabilism' (probability of truth) and 'reliabilism' (probability of good cognitive process) [Pollock/Cruz]
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
One belief may cause another, without being the basis for the second belief [Pollock/Cruz]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
We can't start our beliefs from scratch, because we wouldn't know where to start [Pollock/Cruz]
14. Science / C. Induction / 1. Induction
Enumerative induction gives a universal judgement, while statistical induction gives a proportion [Pollock/Cruz]
14. Science / C. Induction / 6. Bayes's Theorem
Since every tautology has a probability of 1, should we believe all tautologies? [Pollock/Cruz]
14. Science / D. Explanation / 3. Best Explanation / a. Best explanation
Scientific confirmation is best viewed as inference to the best explanation [Pollock/Cruz]
15. Nature of Minds / C. Capacities of Minds / 6. Idealisation
Science idealises the earth's surface, the oceans, continuities, and liquids [Maddy]