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'works', 'The Concept of a Person' and 'Introducing the Philosophy of Mathematics'
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49 ideas
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
15910
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Cantor named the third realm between the finite and the Absolute the 'transfinite' [Cantor, by Lavine]
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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
15905
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Cantor proved the points on a plane are in one-to-one correspondence to the points on a line [Cantor, by Lavine]
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8667
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The 'integers' are the positive and negative natural numbers, plus zero [Friend]
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8668
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The 'rational' numbers are those representable as fractions [Friend]
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8670
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A number is 'irrational' if it cannot be represented as a fraction [Friend]
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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
9983
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Cantor took the ordinal numbers to be primary [Cantor, by Tait]
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8661
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The natural numbers are primitive, and the ordinals are up one level of abstraction [Friend]
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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / d. Natural numbers
17798
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Cantor presented the totality of natural numbers as finite, not infinite [Cantor, by Mayberry]
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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
9971
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Cantor introduced the distinction between cardinals and ordinals [Cantor, by Tait]
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9892
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Cantor showed that ordinals are more basic than cardinals [Cantor, by Dummett]
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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / f. Cardinal numbers
14136
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A cardinal is an abstraction, from the nature of a set's elements, and from their order [Cantor]
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8664
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Cardinal numbers answer 'how many?', with the order being irrelevant [Friend]
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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
15906
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Cantor tried to prove points on a line matched naturals or reals - but nothing in between [Cantor, by Lavine]
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11015
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Cantor's diagonal argument proved you can't list all decimal numbers between 0 and 1 [Cantor, by Read]
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8671
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The 'real' numbers (rationals and irrationals combined) is the Continuum, which has no gaps [Friend]
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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / h. Reals from Cauchy
15903
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A real is associated with an infinite set of infinite Cauchy sequences of rationals [Cantor, by Lavine]
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18251
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Irrational numbers are the limits of Cauchy sequences of rational numbers [Cantor, by Lavine]
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6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
15902
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Irrationals and the Dedekind Cut implied infinite classes, but they seemed to have logical difficulties [Cantor, by Lavine]
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15908
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It was Cantor's diagonal argument which revealed infinities greater than that of the real numbers [Cantor, by Lavine]
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6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
13464
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Cantor proposes that there won't be a potential infinity if there is no actual infinity [Cantor, by Hart,WD]
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6. Mathematics / A. Nature of Mathematics / 5. The Infinite / f. Uncountable infinities
10112
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The naturals won't map onto the reals, so there are different sizes of infinity [Cantor, by George/Velleman]
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6. Mathematics / A. Nature of Mathematics / 5. The Infinite / g. Continuum Hypothesis
17889
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CH: An infinite set of reals corresponds 1-1 either to the naturals or to the reals [Cantor, by Koellner]
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10883
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Cantor's Continuum Hypothesis says there is a gap between the natural and the real numbers [Cantor, by Horsten]
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8733
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The Continuum Hypothesis says there are no sets between the natural numbers and reals [Cantor, by Shapiro]
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13528
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Continuum Hypothesis: there are no sets between N and P(N) [Cantor, by Wolf,RS]
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9555
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Continuum Hypothesis: no cardinal greater than aleph-null but less than cardinality of the continuum [Cantor, by Chihara]
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13447
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Cantor: there is no size between naturals and reals, or between a set and its power set [Cantor, by Hart,WD]
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6. Mathematics / A. Nature of Mathematics / 5. The Infinite / h. Ordinal infinity
8663
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Raising omega to successive powers of omega reveal an infinity of infinities [Friend]
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8662
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The first limit ordinal is omega (greater, but without predecessor), and the second is twice-omega [Friend]
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15893
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Cantor's theory concerns collections which can be counted, using the ordinals [Cantor, by Lavine]
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18174
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Cantor extended ordinals into the transfinite, and they can thus measure infinite cardinalities [Cantor, by Maddy]
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6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
18173
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Cardinality strictly concerns one-one correspondence, to test infinite sameness of size [Cantor, by Maddy]
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6. Mathematics / A. Nature of Mathematics / 5. The Infinite / j. Infinite divisibility
8669
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Between any two rational numbers there is an infinite number of rational numbers [Friend]
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6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
8676
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Is mathematics based on sets, types, categories, models or topology? [Friend]
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6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
10232
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Property extensions outstrip objects, so shortage of objects caused the Caesar problem [Cantor, by Shapiro]
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6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
18176
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Pure mathematics is pure set theory [Cantor]
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8678
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Most mathematical theories can be translated into the language of set theory [Friend]
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6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
8701
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The number 8 in isolation from the other numbers is of no interest [Friend]
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8702
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In structuralism the number 8 is not quite the same in different structures, only equivalent [Friend]
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6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / b. Varieties of structuralism
8699
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Are structures 'ante rem' (before reality), or are they 'in re' (grounded in physics)? [Friend]
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6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / c. Nominalist structuralism
8696
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Structuralist says maths concerns concepts about base objects, not base objects themselves [Friend]
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8695
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Structuralism focuses on relations, predicates and functions, with objects being inessential [Friend]
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6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / d. Platonist structuralism
8700
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'In re' structuralism says that the process of abstraction is pattern-spotting [Friend]
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6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / b. Against mathematical platonism
8681
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The big problem for platonists is epistemic: how do we perceive, intuit, know or detect mathematical facts? [Friend]
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6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
8631
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Cantor says that maths originates only by abstraction from objects [Cantor, by Frege]
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6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / b. Indispensability of mathematics
8712
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Mathematics should be treated as true whenever it is indispensable to our best physical theory [Friend]
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6. Mathematics / C. Sources of Mathematics / 7. Formalism
8716
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Formalism is unconstrained, so cannot indicate importance, or directions for research [Friend]
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6. Mathematics / C. Sources of Mathematics / 10. Constructivism / a. Constructivism
8706
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Constructivism rejects too much mathematics [Friend]
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6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
8707
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Intuitionists typically retain bivalence but reject the law of excluded middle [Friend]
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