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All the ideas for 'New Scientist articles', 'Principia Mathematica' and 'Ontological Ground of Alethic Modality'

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53 ideas

4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
The best known axiomatization of PL is Whitehead/Russell, with four axioms and two rules [Russell/Whitehead, by Hughes/Cresswell]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
Russell saw Reducibility as legitimate for reducing classes to logic [Linsky,B on Russell/Whitehead]
4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory
Russell denies extensional sets, because the null can't be a collection, and the singleton is just its element [Russell/Whitehead, by Shapiro]
We regard classes as mere symbolic or linguistic conveniences [Russell/Whitehead]
5. Theory of Logic / B. Logical Consequence / 7. Strict Implication
Lewis's 'strict implication' preserved Russell's confusion of 'if...then' with implication [Quine on Russell/Whitehead]
Russell's implication means that random sentences imply one another [Lewis,CI on Russell/Whitehead]
5. Theory of Logic / C. Ontology of Logic / 1. Ontology of Logic
Russell unusually saw logic as 'interpreted' (though very general, and neutral) [Russell/Whitehead, by Linsky,B]
5. Theory of Logic / E. Structures of Logic / 6. Relations in Logic
In 'Principia' a new abstract theory of relations appeared, and was applied [Russell/Whitehead, by Gödel]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts
A real number is the class of rationals less than the number [Russell/Whitehead, by Shapiro]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / a. Defining numbers
Russell takes numbers to be classes, but then reduces the classes to numerical quantifiers [Russell/Whitehead, by Bostock]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Russell and Whitehead took arithmetic to be higher-order logic [Russell/Whitehead, by Hodes]
Russell and Whitehead were not realists, but embraced nearly all of maths in logic [Russell/Whitehead, by Friend]
'Principia' lacks a precise statement of the syntax [Gödel on Russell/Whitehead]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / b. Type theory
The ramified theory of types used propositional functions, and covered bound variables [Russell/Whitehead, by George/Velleman]
The Russell/Whitehead type theory was limited, and was not really logic [Friend on Russell/Whitehead]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
In 'Principia Mathematica', logic is exceeded in the axioms of infinity and reducibility, and in the domains [Bernays on Russell/Whitehead]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / a. Constructivism
Russell and Whitehead consider the paradoxes to indicate that we create mathematical reality [Russell/Whitehead, by Friend]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
To avoid vicious circularity Russell produced ramified type theory, but Ramsey simplified it [Russell/Whitehead, by Shapiro]
7. Existence / A. Nature of Existence / 5. Reason for Existence
Current physics says matter and antimatter should have reduced to light at the big bang [New Sci.]
CP violation shows a decay imbalance in matter and antimatter, leading to matter's dominance [New Sci.]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
An object is identical with itself, and no different indiscernible object can share that [Russell/Whitehead, by Adams,RM]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Lewis must specify that all possibilities are in his worlds, making the whole thing circular [Shalkowski, by Sider]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
Russell showed, through the paradoxes, that our basic logical intuitions are self-contradictory [Russell/Whitehead, by Gödel]
14. Science / A. Basis of Science / 4. Prediction
A system can infer the structure of the world by making predictions about it [New Sci.]
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
Neural networks can extract the car-ness of a car, or the chair-ness of a chair [New Sci.]
18. Thought / A. Modes of Thought / 5. Rationality / a. Rationality
No one has yet devised a rationality test [New Sci.]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
The multiple relations theory says assertions about propositions are about their ingredients [Russell/Whitehead, by Linsky,B]
A judgement is a complex entity, of mind and various objects [Russell/Whitehead]
The meaning of 'Socrates is human' is completed by a judgement [Russell/Whitehead]
The multiple relation theory of judgement couldn't explain the unity of sentences [Morris,M on Russell/Whitehead]
Only the act of judging completes the meaning of a statement [Russell/Whitehead]
18. Thought / A. Modes of Thought / 7. Intelligence
About a third of variation in human intelligence is environmental [New Sci.]
People can be highly intelligent, yet very stupid [New Sci.]
18. Thought / B. Mechanics of Thought / 1. Psychology
Psychologists measure personality along five dimensions [New Sci.]
19. Language / D. Propositions / 3. Concrete Propositions
Propositions as objects of judgement don't exist, because we judge several objects, not one [Russell/Whitehead]
27. Natural Reality / A. Classical Physics / 2. Thermodynamics / d. Entropy
Entropy is the only time-asymmetric law, so time may be linked to entropy [New Sci.]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / a. Electrodynamics
Light moves at a constant space-time speed, but its direction is in neither space nor time [New Sci.]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / d. Quantum mechanics
Quantum states are measured by external time, of unknown origin [New Sci.]
The Schrödinger equation describes the evolution of an object's wave function in Hilbert space [New Sci.]
27. Natural Reality / B. Modern Physics / 5. Unified Models / b. String theory
In string theory space-time has a grainy indivisible substructure [New Sci.]
String theory needs at least 10 space-time dimensions [New Sci.]
It is impossible for find a model of actuality among the innumerable models in string theory [New Sci.]
27. Natural Reality / C. Space / 2. Space
Hilbert Space is an abstraction representing all possible states of a quantum system [New Sci.]
27. Natural Reality / C. Space / 6. Space-Time
Einstein's merging of time with space has left us confused about the nature of time [New Sci.]
Space-time may be a geometrical manifestation of quantum entanglement [New Sci.]
Relativity makes time and space jointly basic; quantum theory splits them, and prioritises time [New Sci.]
27. Natural Reality / D. Time / 1. Nature of Time / d. Time as measure
Quantum theory relies on a clock outside the system - but where is it located? [New Sci.]
27. Natural Reality / D. Time / 2. Passage of Time / g. Time's arrow
Entropy is puzzling, so we may need to build new laws which include time directionality [New Sci.]
27. Natural Reality / E. Cosmology / 7. Black Holes
General relativity predicts black holes, as former massive stars, and as galaxy centres [New Sci.]
Black holes have entropy, but general relativity says they are unstructured, and lack entropy [New Sci.]
27. Natural Reality / E. Cosmology / 8. Dark Matter
84.5 percent of the universe is made of dark matter [New Sci.]
27. Natural Reality / F. Chemistry / 1. Chemistry
We are halfway to synthesising any molecule we want [New Sci.]
27. Natural Reality / F. Chemistry / 3. Periodic Table
Chemistry just needs the periodic table, and protons, electrons and neutrinos [New Sci.]