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All the ideas for 'fragments/reports', 'Frege's Concept of Numbers as Objects' and 'First-Order Logic'

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90 ideas

1. Philosophy / B. History of Ideas / 2. Ancient Thought
Epicurus accepted God in his popular works, but not in his writings on nature [Epicurus, by Sext.Empiricus]
1. Philosophy / C. History of Philosophy / 1. History of Philosophy
We can only learn from philosophers of the past if we accept the risk of major misrepresentation [Wright,C]
1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
Slavery to philosophy brings true freedom [Epicurus]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
Philosophy aims at a happy life, through argument and discussion [Epicurus]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / b. Philosophy as transcendent
We should come to philosophy free from any taint of culture [Epicurus]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / f. Philosophy as healing
The aim of medicine is removal of sickness, and philosophy similarly removes our affections [Epicurus]
1. Philosophy / F. Analytic Philosophy / 2. Analysis by Division
We should say nothing of the whole if our contact is with the parts [Epicurus, by Plutarch]
2. Reason / C. Styles of Reason / 1. Dialectic
Epicurus despises and laughs at the whole of dialectic [Epicurus, by Cicero]
The best way to understand a philosophical idea is to defend it [Wright,C]
2. Reason / D. Definition / 7. Contextual Definition
The attempt to define numbers by contextual definition has been revived [Wright,C, by Fine,K]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Epicurus rejected excluded middle, because accepting it for events is fatalistic [Epicurus, by Cicero]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / e. or
Epicureans say disjunctions can be true whiile the disjuncts are not true [Epicurus, by Cicero]
5. Theory of Logic / F. Referring in Logic / 1. Naming / d. Singular terms
An expression refers if it is a singular term in some true sentences [Wright,C, by Dummett]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W]
There are three different standard presentations of semantics [Hodges,W]
I |= φ means that the formula φ is true in the interpretation I [Hodges,W]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W]
Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W]
5. Theory of Logic / K. Features of Logics / 6. Compactness
If a first-order theory entails a sentence, there is a finite subset of the theory which entails it [Hodges,W]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
Number theory aims at the essence of natural numbers, giving their nature, and the epistemology [Wright,C]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
One could grasp numbers, and name sizes with them, without grasping ordering [Wright,C]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / d. Counting via concepts
Instances of a non-sortal concept can only be counted relative to a sortal concept [Wright,C]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
Wright thinks Hume's Principle is more fundamental to cardinals than the Peano Axioms are [Wright,C, by Heck]
There are five Peano axioms, which can be expressed informally [Wright,C]
Number truths are said to be the consequence of PA - but it needs semantic consequence [Wright,C]
What facts underpin the truths of the Peano axioms? [Wright,C]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / c. Fregean numbers
Sameness of number is fundamental, not counting, despite children learning that first [Wright,C]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / d. Hume's Principle
We derive Hume's Law from Law V, then discard the latter in deriving arithmetic [Wright,C, by Fine,K]
Frege has a good system if his 'number principle' replaces his basic law V [Wright,C, by Friend]
Wright says Hume's Principle is analytic of cardinal numbers, like a definition [Wright,C, by Heck]
It is 1-1 correlation of concepts, and not progression, which distinguishes natural number [Wright,C]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
If numbers are extensions, Frege must first solve the Caesar problem for extensions [Wright,C]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
A 'set' is a mathematically well-behaved class [Hodges,W]
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
Number platonism says that natural number is a sortal concept [Wright,C]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
We can't use empiricism to dismiss numbers, if numbers are our main evidence against empiricism [Wright,C]
6. Mathematics / C. Sources of Mathematics / 5. Numbers as Adjectival
Treating numbers adjectivally is treating them as quantifiers [Wright,C]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
The Peano Axioms, and infinity of cardinal numbers, are logical consequences of how we explain cardinals [Wright,C]
The aim is to follow Frege's strategy to derive the Peano Axioms, but without invoking classes [Wright,C]
Wright has revived Frege's discredited logicism [Wright,C, by Benardete,JA]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Logicism seemed to fail by Russell's paradox, Gödel's theorems, and non-logical axioms [Wright,C]
The standard objections are Russell's Paradox, non-logical axioms, and Gödel's theorems [Wright,C]
7. Existence / A. Nature of Existence / 2. Types of Existence
The idea that 'exist' has multiple senses is not coherent [Wright,C]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / b. Commitment of quantifiers
Singular terms in true sentences must refer to objects; there is no further question about their existence [Wright,C]
9. Objects / A. Existence of Objects / 2. Abstract Objects / c. Modern abstracta
Contextually defined abstract terms genuinely refer to objects [Wright,C, by Dummett]
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
Sortal concepts cannot require that things don't survive their loss, because of phase sortals [Wright,C]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / b. Recollection doctrine
We can't seek for things if we have no idea of them [Epicurus, by Diog. Laertius]
12. Knowledge Sources / A. A Priori Knowledge / 9. A Priori from Concepts
To name something, you must already have an idea of what it is [Epicurus, by Diog. Laertius]
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / d. Secondary qualities
Epicurus says colours are relative to the eye, not intrinsic to bodies [Epicurus, by Plutarch]
12. Knowledge Sources / B. Perception / 5. Interpretation
Sensations cannot be judged, because similar sensations have equal value, and different ones have nothing in common [Epicurus, by Diog. Laertius]
12. Knowledge Sources / D. Empiricism / 1. Empiricism
The criteria of truth are senses, preconceptions and passions [Epicurus, by Diog. Laertius]
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
Reason can't judge senses, as it is based on them [Epicurus, by Diog. Laertius]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Epicurus denied knowledge in order to retain morality or hedonism as the highest values [Nietzsche on Epicurus]
13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism
Epicurus says if one of a man's senses ever lies, none of his senses should ever be believed [Epicurus, by Cicero]
13. Knowledge Criteria / E. Relativism / 1. Relativism
If two people disagree over taste, who is right? [Epicurus, by Plutarch]
Bath water is too hot for some, too cold for others [Epicurus, by Plutarch]
When entering a dark room it is colourless, but colour gradually appears [Epicurus]
15. Nature of Minds / A. Nature of Mind / 2. Psuche
The rational soul is in the chest, and the non-rational soul is spread through the body [Epicurus]
Soul is made of four stuffs, giving warmth, rest, motion and perception [Epicurus, by Aetius]
16. Persons / F. Free Will / 1. Nature of Free Will
Epicurus was the first to see the free will problem, and he was a libertarian [Epicurus, by Long/Sedley]
16. Persons / F. Free Will / 2. Sources of Free Will
Epicurus showed that the swerve can give free motion in the atoms [Epicurus, by Diogenes of Oen.]
16. Persons / F. Free Will / 4. For Free Will
There is no necessity to live with necessity [Epicurus]
17. Mind and Body / E. Mind as Physical / 7. Anti-Physicalism / a. Physicalism critique
How can pleasure or judgement occur in a heap of atoms? [Sext.Empiricus on Epicurus]
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
A concept is only a sortal if it gives genuine identity [Wright,C]
'Sortal' concepts show kinds, use indefinite articles, and require grasping identities [Wright,C]
18. Thought / D. Concepts / 4. Structure of Concepts / b. Analysis of concepts
Entities fall under a sortal concept if they can be used to explain identity statements concerning them [Wright,C]
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
If we can establish directions from lines and parallelism, we were already committed to directions [Wright,C]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
A milder claim is that understanding requires some evidence of that understanding [Wright,C]
19. Language / B. Reference / 1. Reference theories
If apparent reference can mislead, then so can apparent lack of reference [Wright,C]
19. Language / C. Assigning Meanings / 3. Predicates
We can accept Frege's idea of object without assuming that predicates have a reference [Wright,C]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / g. Moral responsibility
It was Epicurus who made the question of the will's freedom central to ethics [Epicurus, by Grayling]
22. Metaethics / B. Value / 2. Values / h. Fine deeds
Fine things are worthless if they give no pleasure [Epicurus]
22. Metaethics / C. The Good / 1. Goodness / f. Good as pleasure
Pleasure is the chief good because it is the most natural, especially for animals [Epicurus, by Diog. Laertius]
22. Metaethics / C. The Good / 3. Pleasure / b. Types of pleasure
Pains of the soul are worse than pains of the body, because it feels the past and future [Epicurus, by Diog. Laertius]
Pleasures only differ in their duration and the part of the body affected [Epicurus]
The end for Epicurus is static pleasure [Epicurus, by Annas]
23. Ethics / B. Contract Ethics / 1. Contractarianism
Justice has no independent existence, but arises entirely from keeping contracts [Epicurus]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / c. Motivation for virtue
We choose virtue because of pleasure, not for its own sake [Epicurus, by Diog. Laertius]
23. Ethics / C. Virtue Theory / 4. External Goods / a. External goods
A wise man would be happy even under torture [Epicurus, by Diog. Laertius]
23. Ethics / C. Virtue Theory / 4. External Goods / d. Friendship
Friendship is by far the most important ingredient of a complete and happy life [Epicurus]
25. Social Practice / F. Life Issues / 4. Suicide
Wise men should partake of life even if they go blind [Epicurus, by Diog. Laertius]
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / c. Purpose denied
Only Epicurus denied purpose in nature, for the whole world, or for its parts [Epicurus, by Annas]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / g. Atomism
Democritus says atoms have size and shape, and Epicurus added weight [Epicurus, by Ps-Plutarch]
Atoms don't swerve by being struck, because they move in parallel, so the swerve is uncaused [Cicero on Epicurus]
What causes atomic swerves? Do they draw lots? What decides the size or number of swerves? [Cicero on Epicurus]
27. Natural Reality / D. Time / 1. Nature of Time / a. Absolute time
Stoics say time is incorporeal and self-sufficient; Epicurus says it is a property of properties of things [Epicurus]
28. God / A. Divine Nature / 2. Divine Nature
For Epicureans gods are made of atoms, and are not eternal [Epicurus, by Cicero]
28. God / B. Proving God / 2. Proofs of Reason / a. Ontological Proof
Epicurus saw that gods must exist, because nature has imprinted them on human minds [Epicurus, by Cicero]
28. God / C. Attitudes to God / 5. Atheism
Some say Epicurus only pretended to believe in the gods, so as not to offend Athenians [Epicurus, by Cicero]
29. Religion / D. Religious Issues / 1. Religious Commitment / a. Religious Belief
If god answered prayers we would be destroyed, because we pray for others to suffer [Epicurus]