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All the ideas for 'Logical Consequence', 'Popular Scientific Lectures' and 'Principle Doctrines ('Kuriai Doxai') (frags)'

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20 ideas

1. Philosophy / A. Wisdom / 2. Wise People
It is a great good to show reverence for a wise man [Epicurus]
     Full Idea: To show reverence for a wise man is itself a great good for him who reveres [the wise man].
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 32)
     A reaction: It is characteristic of Epicurus to move up a level in his thinking, and not merely respect wisdom, but ask after the value of his own respect. Compare Idea 14517. Nice.
1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
In the study of philosophy, pleasure and knowledge arrive simultaneously [Epicurus]
     Full Idea: In philosophy the pleasure accompanies the knowledge. For the enjoyment does not come after the learning but the learning and the enjoyment are simultaneous.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 27)
1. Philosophy / G. Scientific Philosophy / 2. Positivism
Laws of nature are just records of regularities and correlations, with concepts to make recording them easier [Mach, by Harré]
     Full Idea: For Mach, the laws of nature are simply the compendious record of sensory regularities, correlations of elements. Any additional concepts are no more than symbols or devices for the convenient recording of general sensory patterns.
     From: report of Ernst Mach (Popular Scientific Lectures [1894], pp.201-5) by Rom Harré - Laws of Nature 2
     A reaction: Mach is the high priest of scientific positivism, which is really just hard-line empiricism.
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall]
     Full Idea: 'Equivocation' is when the terms do not mean the same thing in the premises and in the conclusion.
     From: JC Beall / G Restall (Logical Consequence [2005], Intro)
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
Formal logic is invariant under permutations, or devoid of content, or gives the norms for thought [Beall/Restall]
     Full Idea: Logic is purely formal either when it is invariant under permutation of object (Tarski), or when it has totally abstracted away from all contents, or it is the constitutive norms for thought.
     From: JC Beall / G Restall (Logical Consequence [2005], 2)
     A reaction: [compressed] The third account sounds rather woolly, and the second one sounds like a tricky operation, but the first one sounds clear and decisive, so I vote for Tarski.
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
Logical consequence needs either proofs, or absence of counterexamples [Beall/Restall]
     Full Idea: Technical work on logical consequence has either focused on proofs, where validity is the existence of a proof of the conclusions from the premises, or on models, which focus on the absence of counterexamples.
     From: JC Beall / G Restall (Logical Consequence [2005], 3)
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
Logical consequence is either necessary truth preservation, or preservation based on interpretation [Beall/Restall]
     Full Idea: Two different views of logical consequence are necessary truth-preservation (based on modelling possible worlds; favoured by Realists), or truth-preservation based on the meanings of the logical vocabulary (differing in various models; for Anti-Realists).
     From: JC Beall / G Restall (Logical Consequence [2005], 2)
     A reaction: Thus Dummett prefers the second view, because the law of excluded middle is optional. My instincts are with the first one.
5. Theory of Logic / B. Logical Consequence / 8. Material Implication
A step is a 'material consequence' if we need contents as well as form [Beall/Restall]
     Full Idea: A logical step is a 'material consequence' and not a formal one, if we need the contents as well as the structure or form.
     From: JC Beall / G Restall (Logical Consequence [2005], 2)
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
A 'logical truth' (or 'tautology', or 'theorem') follows from empty premises [Beall/Restall]
     Full Idea: If a conclusion follows from an empty collection of premises, it is true by logic alone, and is a 'logical truth' (sometimes a 'tautology'), or, in the proof-centred approach, 'theorems'.
     From: JC Beall / G Restall (Logical Consequence [2005], 4)
     A reaction: These truths are written as following from the empty set Φ. They are just implications derived from the axioms and the rules.
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Models are mathematical structures which interpret the non-logical primitives [Beall/Restall]
     Full Idea: Models are abstract mathematical structures that provide possible interpretations for each of the non-logical primitives in a formal language.
     From: JC Beall / G Restall (Logical Consequence [2005], 3)
6. Mathematics / B. Foundations for Mathematics / 2. Proof in Mathematics
Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall]
     Full Idea: There are many proof-systems, the main being Hilbert proofs (with simple rules and complex axioms), or natural deduction systems (with few axioms and many rules, and the rules constitute the meaning of the connectives).
     From: JC Beall / G Restall (Logical Consequence [2005], 3)
9. Objects / A. Existence of Objects / 5. Individuation / b. Individuation by properties
Bodies are combinations of shape, size, resistance and weight [Epicurus]
     Full Idea: Epicurus said that body was conceived as an aggregate of shape and size and resistance and weight.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE])
     A reaction: [Source Sextus 'Adversus Mathematicos' 10.257] Note that this is how we 'conceive' them. They might be intrinsically different, except that Epicurus is pretty much a phenomenalist.
16. Persons / F. Free Will / 6. Determinism / a. Determinism
If everything is by necessity, then even denials of necessity are by necessity [Epicurus]
     Full Idea: He who claims that everything occurs by necessity has no complaint against him who claims that everything does not occur by necessity. For he makes the very claim in question by necessity.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 40)
22. Metaethics / C. The Good / 2. Happiness / c. Value of happiness
What happens to me if I obtain all my desires, and what if I fail? [Epicurus]
     Full Idea: One should bring this question to bear on all one's desires: what will happen to me if what is sought by desire is achieved, and what will happen if it is not?
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 71)
     A reaction: Yet another example of Epicurus moving up a level in his thinking about ethical issues, as in Idea 14517 and Idea 14519. The mark of a true philosopher. This seems to be a key idea for wisdom - to think further ahead than merely what you desire.
22. Metaethics / C. The Good / 3. Pleasure / e. Role of pleasure
Pleasure and virtue entail one another [Epicurus]
     Full Idea: It is not possible to live pleasantly without living intelligently and finely and justly, nor to live intelligently and finely and justly without living pleasantly.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 5), quoted by Julia Annas - The Morality of Happiness Ch.16
     A reaction: A person with all these virtues might still suffer from depression. And I don't see why having limited intelligence should stop someone from living pleasantly. Just be warm-hearted.
23. Ethics / B. Contract Ethics / 1. Contractarianism
Justice is merely a contract about not harming or being harmed [Epicurus]
     Full Idea: There is no such things as justice in itself; in people's relations with one another in any place and at any time it is a contract about not harming or being harmed.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 33), quoted by Julia Annas - The Morality of Happiness 13.2
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / e. Character
We value our own character, whatever it is, and we should respect the characters of others [Epicurus]
     Full Idea: We value our characters as our own personal possessions, whether they are good and envied by men or not. We must regard our neighbours' characters thus too, if they are respectable.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 15)
     A reaction: I like this because it introduces a metaethical dimension to the whole problem of virtue. We should value our own character - so should we try to improve it? Should we improve so much as to become unrecognisable?
23. Ethics / C. Virtue Theory / 3. Virtues / c. Justice
Justice is a pledge of mutual protection [Epicurus]
     Full Idea: The justice of nature is a pledge of reciprocal usefulness, neither to harm one another nor to be harmed.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 31)
     A reaction: Notice that justice is not just reciprocal usefulness, but a 'pledge' to that effect. This implies a metaethical value of trust and honesty in keeping the pledge. Is it better to live by the pledge, or to be always spontaneously useful?
24. Political Theory / B. Nature of a State / 2. State Legitimacy / c. Social contract
A law is not just if it is not useful in mutual associations [Epicurus]
     Full Idea: If someone passes a law and it does not turn out to be in accord with what is useful in mutual associations, this no longer possesses the nature of justice.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 37)
25. Social Practice / F. Life Issues / 4. Suicide
It is small-minded to find many good reasons for suicide [Epicurus]
     Full Idea: He is utterly small-minded for whom there are many plausible reasons for committing suicide.
     From: Epicurus (Principle Doctrines ('Kuriai Doxai') (frags) [c.290 BCE], 38)
     A reaction: It is a pity that the insult of 'small-minded' has slipped out of philosophy. The Greeks use it all the time, and know exactly what it means. We all recognise small-mindedness, and it is a great (and subtle) vice.