Combining Philosophers

All the ideas for Hermarchus, Brian Ellis and George Cantor

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157 ideas

1. Philosophy / E. Nature of Metaphysics / 1. Nature of Metaphysics
Metaphysics aims at the simplest explanation, without regard to testability [Ellis]
1. Philosophy / E. Nature of Metaphysics / 4. Metaphysics as Science
Ontology should give insight into or an explanation of the world revealed by science [Ellis]
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Essentialism says metaphysics can't be done by analysing unreliable language [Ellis]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
Real possibility and necessity has the logic of S5, which links equivalence classes of worlds of the same kind [Ellis]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Trying to represent curves, we study arbitrary functions, leading to the ordinals, which produces set theory [Cantor, by Lavine]
Cantor developed sets from a progression into infinity by addition, multiplication and exponentiation [Cantor, by Lavine]
A set is a collection into a whole of distinct objects of our intuition or thought [Cantor]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / c. Basic theorems of ST
Cantor's Theorem: for any set x, its power set P(x) has more members than x [Cantor, by Hart,WD]
Cantor proved that all sets have more subsets than they have members [Cantor, by Bostock]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
If a set is 'a many thought of as one', beginners should protest against singleton sets [Cantor, by Lewis]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / d. Infinite Sets
Cantor showed that supposed contradictions in infinity were just a lack of clarity [Cantor, by Potter]
The continuum is the powerset of the integers, which moves up a level [Cantor, by Clegg]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Cantor gives informal versions of ZF axioms as ways of getting from one set to another [Cantor, by Lake]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / d. Axiom of Unions III
The Axiom of Union dates from 1899, and seems fairly obvious [Cantor, by Maddy]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / b. Combinatorial sets
Cantor's sets were just collections, but Dedekind's were containers [Cantor, by Oliver/Smiley]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
We can base logic on acceptability, and abandon the Fregean account by truth-preservation [Ellis]
5. Theory of Logic / I. Semantics of Logic / 5. Extensionalism
Humean conceptions of reality drive the adoption of extensional logic [Ellis]
5. Theory of Logic / K. Features of Logics / 8. Enumerability
There are infinite sets that are not enumerable [Cantor, by Smith,P]
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / b. Cantor's paradox
Cantor's Paradox: the power set of the universe must be bigger than the universe, yet a subset of it [Cantor, by Hart,WD]
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / e. Mirimanoff's paradox
The powerset of all the cardinal numbers is required to be greater than itself [Cantor, by Friend]
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
Cantor named the third realm between the finite and the Absolute the 'transfinite' [Cantor, by Lavine]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
Cantor proved the points on a plane are in one-to-one correspondence to the points on a line [Cantor, by Lavine]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
Cantor took the ordinal numbers to be primary [Cantor, by Tait]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / d. Natural numbers
Cantor presented the totality of natural numbers as finite, not infinite [Cantor, by Mayberry]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Cantor introduced the distinction between cardinals and ordinals [Cantor, by Tait]
Cantor showed that ordinals are more basic than cardinals [Cantor, by Dummett]
Ordinals are generated by endless succession, followed by a limit ordinal [Cantor, by Lavine]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / f. Cardinal numbers
A cardinal is an abstraction, from the nature of a set's elements, and from their order [Cantor]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
Cantor tried to prove points on a line matched naturals or reals - but nothing in between [Cantor, by Lavine]
Cantor's diagonal argument proved you can't list all decimal numbers between 0 and 1 [Cantor, by Read]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / h. Reals from Cauchy
A real is associated with an infinite set of infinite Cauchy sequences of rationals [Cantor, by Lavine]
Irrational numbers are the limits of Cauchy sequences of rational numbers [Cantor, by Lavine]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Irrationals and the Dedekind Cut implied infinite classes, but they seemed to have logical difficulties [Cantor, by Lavine]
It was Cantor's diagonal argument which revealed infinities greater than that of the real numbers [Cantor, by Lavine]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
Cantor proposes that there won't be a potential infinity if there is no actual infinity [Cantor, by Hart,WD]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / f. Uncountable infinities
The naturals won't map onto the reals, so there are different sizes of infinity [Cantor, by George/Velleman]
Cantor needed Power Set for the reals, but then couldn't count the new collections [Cantor, by Lavine]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / g. Continuum Hypothesis
CH: An infinite set of reals corresponds 1-1 either to the naturals or to the reals [Cantor, by Koellner]
Cantor: there is no size between naturals and reals, or between a set and its power set [Cantor, by Hart,WD]
Cantor's Continuum Hypothesis says there is a gap between the natural and the real numbers [Cantor, by Horsten]
Continuum Hypothesis: there are no sets between N and P(N) [Cantor, by Wolf,RS]
Continuum Hypothesis: no cardinal greater than aleph-null but less than cardinality of the continuum [Cantor, by Chihara]
The Continuum Hypothesis says there are no sets between the natural numbers and reals [Cantor, by Shapiro]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / h. Ordinal infinity
Cantor's theory concerns collections which can be counted, using the ordinals [Cantor, by Lavine]
Cantor extended ordinals into the transfinite, and they can thus measure infinite cardinalities [Cantor, by Maddy]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
Cardinality strictly concerns one-one correspondence, to test infinite sameness of size [Cantor, by Maddy]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Mathematics is the formal study of the categorical dimensions of things [Ellis]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / c. Fregean numbers
The 'extension of a concept' in general may be quantitatively completely indeterminate [Cantor]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
Property extensions outstrip objects, so shortage of objects caused the Caesar problem [Cantor, by Shapiro]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Pure mathematics is pure set theory [Cantor]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
Cantor says that maths originates only by abstraction from objects [Cantor, by Frege]
7. Existence / B. Change in Existence / 2. Processes
Objects and substances are a subcategory of the natural kinds of processes [Ellis]
7. Existence / B. Change in Existence / 4. Events / c. Reduction of events
A physical event is any change of distribution of energy [Ellis]
8. Modes of Existence / B. Properties / 1. Nature of Properties
The extension of a property is a contingent fact, so cannot be the essence of the property [Ellis]
8. Modes of Existence / B. Properties / 3. Types of Properties
Properties are 'dispositional', or 'categorical' (the latter as 'block' or 'intrinsic' structures) [Ellis, by PG]
8. Modes of Existence / B. Properties / 5. Natural Properties
There is no property of 'fragility', as things are each fragile in a distinctive way [Ellis]
Physical properties are those relevant to how a physical system might act [Ellis]
8. Modes of Existence / B. Properties / 6. Categorical Properties
Typical 'categorical' properties are spatio-temporal, such as shape [Ellis]
The property of 'being an electron' is not of anything, and only electrons could have it [Ellis]
The passive view of nature says categorical properties are basic, but others say dispositions [Ellis]
I support categorical properties, although most people only want causal powers [Ellis]
Essentialism needs categorical properties (spatiotemporal and numerical relations) and dispositions [Ellis]
Spatial, temporal and numerical relations have causal roles, without being causal [Ellis]
8. Modes of Existence / B. Properties / 10. Properties as Predicates
'Being a methane molecule' is not a property - it is just a predicate [Ellis]
8. Modes of Existence / B. Properties / 11. Properties as Sets
Properties and relations are discovered, so they can't be mere sets of individuals [Ellis]
8. Modes of Existence / B. Properties / 12. Denial of Properties
Redness is not a property as it is not mind-independent [Ellis]
8. Modes of Existence / C. Powers and Dispositions / 1. Powers
Space, time, and some other basics, are not causal powers [Ellis]
Causal powers must necessarily act the way they do [Ellis]
Causal powers are often directional (e.g. centripetal, centrifugal, circulatory) [Ellis]
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
Causal powers can't rest on things which lack causal power [Ellis]
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
Basic powers may not be explained by structure, if at the bottom level there is no structure [Ellis]
Maybe dispositions can be explained by intrinsic properties or structures [Ellis]
8. Modes of Existence / C. Powers and Dispositions / 5. Powers and Properties
Properties have powers; they aren't just ways for logicians to classify objects [Ellis]
Categoricals exist to influence powers. Such as structures, orientations and magnitudes [Ellis, by Williams,NE]
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / a. Dispositions
The most fundamental properties of nature (mass, charge, spin ...) all seem to be dispositions [Ellis]
Nearly all fundamental properties of physics are dispositional [Ellis]
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / b. Dispositions and powers
A causal power is a disposition to produce forces [Ellis]
Powers are dispositions of the essences of kinds that involve them in causation [Ellis]
Causal powers are a proper subset of the dispositional properties [Ellis]
8. Modes of Existence / D. Universals / 1. Universals
There are 'substantive' (objects of some kind), 'dynamic' (events of some kind) and 'property' universals [Ellis]
Universals are all types of natural kind [Ellis]
9. Objects / C. Structure of Objects / 1. Structure of an Object
Categorical properties depend only on the structures they represent [Ellis]
9. Objects / D. Essence of Objects / 1. Essences of Objects
Kripke and others have made essentialism once again respectable [Ellis]
9. Objects / D. Essence of Objects / 2. Types of Essence
'Individual essences' fix a particular individual, and 'kind essences' fix the kind it belongs to [Ellis]
9. Objects / D. Essence of Objects / 3. Individual Essences
Scientific essentialism doesn't really need Kripkean individual essences [Ellis]
9. Objects / D. Essence of Objects / 5. Essence as Kind
A real essence is a kind's distinctive properties [Ellis]
9. Objects / D. Essence of Objects / 9. Essence and Properties
Essential properties are usually quantitatively determinate [Ellis]
9. Objects / D. Essence of Objects / 13. Nominal Essence
'Real essence' makes it what it is; 'nominal essence' makes us categorise it a certain way [Ellis]
9. Objects / D. Essence of Objects / 15. Against Essentialism
The old idea that identity depends on essence and behaviour is rejected by the empiricists [Ellis]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
One thing can look like something else, without being the something else [Ellis]
10. Modality / A. Necessity / 3. Types of Necessity
Necessities are distinguished by their grounds, not their different modalities [Ellis]
10. Modality / A. Necessity / 5. Metaphysical Necessity
Metaphysical necessity holds between things in the world and things they make true [Ellis]
10. Modality / B. Possibility / 1. Possibility
Scientific essentialists say science should define the limits of the possible [Ellis]
10. Modality / C. Sources of Modality / 1. Sources of Necessity
Metaphysical necessities are those depending on the essential nature of things [Ellis]
10. Modality / C. Sources of Modality / 5. Modality from Actuality
Essentialists deny possible worlds, and say possibilities are what is compatible with the actual world [Ellis]
10. Modality / C. Sources of Modality / 6. Necessity from Essence
Individual essences necessitate that individual; natural kind essences necessitate kind membership [Ellis]
Metaphysical necessities are true in virtue of the essences of things [Ellis]
10. Modality / D. Knowledge of Modality / 3. A Posteriori Necessary
Essentialists say natural laws are in a new category: necessary a posteriori [Ellis]
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
Imagination tests what is possible for all we know, not true possibility [Ellis]
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
Possible worlds realism is only needed to give truth conditions for modals and conditionals [Ellis]
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / b. Primary/secondary
Essentialists mostly accept the primary/secondary qualities distinction [Ellis]
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / c. Primary qualities
Primary qualities are number, figure, size, texture, motion, configuration, impenetrability and (?) mass [Ellis]
14. Science / B. Scientific Theories / 2. Aim of Science
Science aims to explain things, not just describe them [Ellis]
14. Science / C. Induction / 3. Limits of Induction
If events are unconnected, then induction cannot be solved [Ellis]
14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem
Emeralds are naturally green, and only an external force could turn them blue [Ellis]
14. Science / D. Explanation / 2. Types of Explanation / c. Explanations by coherence
Good explanations unify [Ellis]
14. Science / D. Explanation / 2. Types of Explanation / f. Necessity in explanations
Essentialists don't infer from some to all, but from essences to necessary behaviour [Ellis]
14. Science / D. Explanation / 2. Types of Explanation / i. Explanations by mechanism
Explanations of particular events are not essentialist, as they don't reveal essential structures [Ellis]
14. Science / D. Explanation / 2. Types of Explanation / k. Explanations by essence
To give essentialist explanations there have to be natural kinds [Ellis]
15. Nature of Minds / C. Capacities of Minds / 6. Idealisation
The point of models in theories is not to idealise, but to focus on what is essential [Ellis]
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
Infinities expand the bounds of the conceivable; we explore concepts to explore conceivability [Cantor, by Friend]
18. Thought / E. Abstraction / 2. Abstracta by Selection
Cantor says (vaguely) that we abstract numbers from equal sized sets [Hart,WD on Cantor]
We form the image of a cardinal number by a double abstraction, from the elements and from their order [Cantor]
19. Language / C. Assigning Meanings / 3. Predicates
Predicates assert properties, values, denials, relations, conventions, existence and fabrications [Ellis, by PG]
20. Action / B. Preliminaries of Action / 2. Willed Action / c. Agent causation
Regularity theories of causation cannot give an account of human agency [Ellis]
20. Action / C. Motives for Action / 1. Acting on Desires
Humans have variable dispositions, and also power to change their dispositions [Ellis]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
Essentialism fits in with Darwinism, but not with extreme politics of left or right [Ellis]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]
26. Natural Theory / B. Natural Kinds / 1. Natural Kinds
Natural kinds are of objects/substances, or events/processes, or intrinsic natures [Ellis]
The natural kinds are objects, processes and properties/relations [Ellis]
26. Natural Theory / B. Natural Kinds / 2. Defining Kinds
There are natural kinds of processes [Ellis]
26. Natural Theory / B. Natural Kinds / 3. Knowing Kinds
There might be uninstantiated natural kinds, such as transuranic elements which have never occurred [Ellis]
26. Natural Theory / B. Natural Kinds / 4. Source of Kinds
Natural kinds are distinguished by resting on essences [Ellis]
Essentialism says natural kinds are fundamental to nature, and determine the laws [Ellis]
Natural kind structures go right down to the bottom level [Ellis]
26. Natural Theory / B. Natural Kinds / 6. Necessity of Kinds
For essentialists two members of a natural kind must be identical [Ellis]
The whole of our world is a natural kind, so all worlds like it necessarily have the same laws [Ellis]
26. Natural Theory / B. Natural Kinds / 7. Critique of Kinds
If there are borderline cases between natural kinds, that makes them superficial [Ellis]
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
Essentialists regard inanimate objects as genuine causal agents [Ellis]
Essentialists believe causation is necessary, resulting from dispositions and circumstances [Ellis]
A general theory of causation is only possible in an area if natural kinds are involved [Ellis]
26. Natural Theory / D. Laws of Nature / 1. Laws of Nature
For 'passivists' behaviour is imposed on things from outside [Ellis]
The laws of nature imitate the hierarchy of natural kinds [Ellis]
Laws of nature tend to describe ideal things, or ideal circumstances [Ellis]
We must explain the necessity, idealisation, ontology and structure of natural laws [Ellis]
Laws don't exist in the world; they are true of the world [Ellis]
26. Natural Theory / D. Laws of Nature / 2. Types of Laws
Least action is not a causal law, but a 'global law', describing a global essence [Ellis]
26. Natural Theory / D. Laws of Nature / 3. Laws and Generalities
Laws of nature are just descriptions of how things are disposed to behave [Ellis]
26. Natural Theory / D. Laws of Nature / 4. Regularities / a. Regularity theory
Causal relations cannot be reduced to regularities, as they could occur just once [Ellis]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / a. Scientific essentialism
A proton must have its causal role, because without it it wouldn't be a proton [Ellis]
What is most distinctive of scientific essentialism is regarding processes as natural kinds [Ellis]
Scientific essentialism is more concerned with explanation than with identity (Locke, not Kripke) [Ellis]
The ontological fundamentals are dispositions, and also categorical (spatio-temporal and structural) properties [Ellis]
Essentialists say dispositions are basic, rather than supervenient on matter and natural laws [Ellis]
The essence of uranium is its atomic number and its electron shell [Ellis]
A species requires a genus, and its essence includes the essence of the genus [Ellis]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / b. Scientific necessity
A primary aim of science is to show the limits of the possible [Ellis]
For essentialists, laws of nature are metaphysically necessary, being based on essences of natural kinds [Ellis]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / c. Essence and laws
A hierarchy of natural kinds is elaborate ontology, but needed to explain natural laws [Ellis]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / d. Knowing essences
Essentialism requires a clear separation of semantics, epistemology and ontology [Ellis]
Without general principles, we couldn't predict the behaviour of dispositional properties [Ellis]
27. Natural Reality / A. Classical Physics / 1. Mechanics / c. Forces
I deny forces as entities that intervene in causation, but are not themselves causal [Ellis]
27. Natural Reality / A. Classical Physics / 2. Thermodynamics / a. Energy
Energy is the key multi-valued property, vital to scientific realism [Ellis]
27. Natural Reality / C. Space / 3. Points in Space
Cantor proved that three dimensions have the same number of points as one dimension [Cantor, by Clegg]
27. Natural Reality / D. Time / 1. Nature of Time / a. Absolute time
Simultaneity can be temporal equidistance from the Big Bang [Ellis]
27. Natural Reality / D. Time / 3. Parts of Time / e. Present moment
The present is the collapse of the light wavefront from the Big Bang [Ellis]
28. God / A. Divine Nature / 2. Divine Nature
Only God is absolutely infinite [Cantor, by Hart,WD]