Combining Texts

All the ideas for 'The Logic of What Might Have Been', 'Introduction to the Philosophy of Mathematics' and 'The Gay (Joyful) Science'

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81 ideas

1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Grammar only reveals popular metaphysics [Nietzsche]
3. Truth / A. Truth Problems / 3. Value of Truth
Is the will to truth the desire to avoid deception? [Nietzsche]
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / b. Terminology of ML
A world is 'accessible' to another iff the first is possible according to the second [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / d. System T
For metaphysics, T may be the only correct system of modal logic [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B
System B has not been justified as fallacy-free for reasoning on what might have been [Salmon,N]
In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N]
System B implies that possibly-being-realized is an essential property of the world [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
What is necessary is not always necessarily necessary, so S4 is fallacious [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
S5 modal logic ignores accessibility altogether [Salmon,N]
S5 believers say that-things-might-have-been-that-way is essential to ways things might have been [Salmon,N]
The unsatisfactory counterpart-theory allows the retention of S5 [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..) [Salmon,N]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Rejecting double negation elimination undermines reductio proofs [Colyvan]
Showing a disproof is impossible is not a proof, so don't eliminate double negation [Colyvan]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim proved his result for a first-order sentence, and Skolem generalised it [Colyvan]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Axioms are 'categorical' if all of their models are isomorphic [Colyvan]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinal numbers represent order relations [Colyvan]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Intuitionists only accept a few safe infinities [Colyvan]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / j. Infinite divisibility
Infinitesimals were sometimes zero, and sometimes close to zero [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Reducing real numbers to rationals suggested arithmetic as the foundation of maths [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Transfinite induction moves from all cases, up to the limit ordinal [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Most mathematical proofs are using set theory, but without saying so [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Structuralism say only 'up to isomorphism' matters because that is all there is to it [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
If 'in re' structures relies on the world, does the world contain rich enough structures? [Colyvan]
7. Existence / A. Nature of Existence / 3. Being / c. Becoming
We Germans value becoming and development more highly than mere being of what 'is' [Nietzsche]
9. Objects / D. Essence of Objects / 15. Against Essentialism
Any property is attached to anything in some possible world, so I am a radical anti-essentialist [Salmon,N]
10. Modality / A. Necessity / 2. Nature of Necessity
Necessity is thought to require an event, but is only an after-effect of the event [Nietzsche]
10. Modality / A. Necessity / 3. Types of Necessity
Logical possibility contains metaphysical possibility, which contains nomological possibility [Salmon,N]
10. Modality / A. Necessity / 5. Metaphysical Necessity
In the S5 account, nested modalities may be unseen, but they are still there [Salmon,N]
Metaphysical necessity is said to be unrestricted necessity, true in every world whatsoever [Salmon,N]
Bizarre identities are logically but not metaphysically possible, so metaphysical modality is restricted [Salmon,N]
Without impossible worlds, the unrestricted modality that is metaphysical has S5 logic [Salmon,N]
Metaphysical necessity is NOT truth in all (unrestricted) worlds; necessity comes first, and is restricted [Salmon,N]
10. Modality / A. Necessity / 6. Logical Necessity
Logical necessity is free of constraints, and may accommodate all of S5 logic [Salmon,N]
10. Modality / A. Necessity / 7. Natural Necessity
Nomological necessity is expressed with intransitive relations in modal semantics [Salmon,N]
10. Modality / C. Sources of Modality / 5. Modality from Actuality
Necessity and possibility are not just necessity and possibility according to the actual world [Salmon,N]
10. Modality / E. Possible worlds / 1. Possible Worlds / b. Impossible worlds
Impossible worlds are also ways for things to be [Salmon,N]
Denial of impossible worlds involves two different confusions [Salmon,N]
Without impossible worlds, how things might have been is the only way for things to be [Salmon,N]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Possible worlds rely on what might have been, so they can' be used to define or analyse modality [Salmon,N]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Possible worlds are maximal abstract ways that things might have been [Salmon,N]
Possible worlds just have to be 'maximal', but they don't have to be consistent [Salmon,N]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / c. Worlds as propositions
You can't define worlds as sets of propositions, and then define propositions using worlds [Salmon,N]
11. Knowledge Aims / A. Knowledge / 1. Knowledge
The strength of knowledge is not its truth, but its entrenchment in our culture [Nietzsche]
12. Knowledge Sources / B. Perception / 1. Perception
We became increasingly conscious of our sense impressions in order to communicate them [Nietzsche]
13. Knowledge Criteria / B. Internal Justification / 2. Pragmatic justification
We have no organ for knowledge or truth; we only 'know' what is useful to the human herd [Nietzsche]
13. Knowledge Criteria / E. Relativism / 1. Relativism
We assume causes, geometry, motion, bodies etc to live, but they haven't been proved [Nietzsche]
13. Knowledge Criteria / E. Relativism / 3. Subjectivism
Nietzsche's perspectivism says our worldview depends on our personality [Nietzsche, by Fogelin]
It would be absurd to say we are only permitted our own single perspective [Nietzsche]
14. Science / C. Induction / 6. Bayes's Theorem
Probability supports Bayesianism better as degrees of belief than as ratios of frequencies [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
Mathematics can reveal structural similarities in diverse systems [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / f. Necessity in explanations
Mathematics can show why some surprising events have to occur [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / m. Explanation by proof
Proof by cases (by 'exhaustion') is said to be unexplanatory [Colyvan]
Reductio proofs do not seem to be very explanatory [Colyvan]
If inductive proofs hold because of the structure of natural numbers, they may explain theorems [Colyvan]
Can a proof that no one understands (of the four-colour theorem) really be a proof? [Colyvan]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / d. Purpose of consciousness
All of our normal mental life could be conducted without consciousness [Nietzsche]
Only the need for communication has led to consciousness developing [Nietzsche]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / e. Cause of consciousness
Only our conscious thought is verbal, and this shows the origin of consciousness [Nietzsche]
15. Nature of Minds / B. Features of Minds / 2. Unconscious Mind
Most of our lives, even the important parts, take place outside of consciousness [Nietzsche]
Whatever moves into consciousness becomes thereby much more superficial [Nietzsche]
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
Mathematical generalisation is by extending a system, or by abstracting away from it [Colyvan]
16. Persons / C. Self-Awareness / 3. Limits of Introspection
'Know thyself' is impossible and ridiculous [Nietzsche]
18. Thought / A. Modes of Thought / 1. Thought
Thoughts cannot be fully reproduced in words [Nietzsche]
18. Thought / A. Modes of Thought / 5. Rationality / a. Rationality
Most of our intellectual activity is unconscious [Nietzsche]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism
Why do you listen to the voice of your conscience? [Nietzsche]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / f. Übermensch
Higher human beings see and hear far more than others, and do it more thoughtfully [Nietzsche]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / g. Will to power
A morality ranks human drives and actions, for the sake of the herd, and subordinating individuals [Nietzsche]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
Nietzsche thought it 'childish' to say morality isn't binding because it varies between cultures [Nietzsche, by Foot]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / c. Particularism
No two actions are the same [Nietzsche]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / d. Virtue theory critique
Many virtues are harmful traps, but that is why other people praise them [Nietzsche]
23. Ethics / C. Virtue Theory / 3. Virtues / f. Compassion
You cannot advocate joyful wisdom while rejecting pity, because the two are complementary [Scruton on Nietzsche]
23. Ethics / D. Deontological Ethics / 4. Categorical Imperative
To see one's own judgement as a universal law is selfish [Nietzsche]
23. Ethics / F. Existentialism / 1. Existentialism
We should give style to our character - by applying an artistic plan to its strengths and weaknesses [Nietzsche]
23. Ethics / F. Existentialism / 2. Nihilism
The ethical teacher exists to give purpose to what happens necessarily and without purpose [Nietzsche]
23. Ethics / F. Existentialism / 4. Boredom
To ward off boredom at any cost is vulgar [Nietzsche]
23. Ethics / F. Existentialism / 7. Existential Action
The best life is the dangerous life [Nietzsche]
23. Ethics / F. Existentialism / 8. Eternal Recurrence
Imagine if before each of your actions you had to accept repeating the action over and over again [Nietzsche]
Nietzsche says facing up to the eternal return of meaninglessness is the response to nihilism [Nietzsche, by Critchley]
28. God / C. Attitudes to God / 5. Atheism
God is dead, and we have killed him [Nietzsche]