Combining Texts

All the ideas for 'Gorgias', 'On the Philosophy of Logic' and 'Model Theory'

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44 ideas

1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
Is a gifted philosopher unmanly if he avoids the strife of the communal world? [Plato]
2. Reason / A. Nature of Reason / 1. On Reason
We reach 'reflective equilibrium' when intuitions and theory completely align [Fisher]
2. Reason / C. Styles of Reason / 2. Elenchus
In "Gorgias" Socrates is confident that his 'elenchus' will decide moral truth [Vlastos on Plato]
We should test one another, by asking and answering questions [Plato]
2. Reason / D. Definition / 7. Contextual Definition
The idea that groups of concepts could be 'implicitly defined' was abandoned [Hodges,W]
4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
Three-valued logic says excluded middle and non-contradition are not tautologies [Fisher]
4. Formal Logic / E. Nonclassical Logics / 4. Fuzzy Logic
Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
Since first-order languages are complete, |= and |- have the same meaning [Hodges,W]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
|= in model-theory means 'logical consequence' - it holds in all models [Hodges,W]
5. Theory of Logic / C. Ontology of Logic / 2. Platonism in Logic
Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher]
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
|= should be read as 'is a model for' or 'satisfies' [Hodges,W]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory studies formal or natural language-interpretation using set-theory [Hodges,W]
A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W]
Models in model theory are structures, not sets of descriptions [Hodges,W]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
First-order logic can't discriminate between one infinite cardinal and another [Hodges,W]
7. Existence / D. Theories of Reality / 10. Vagueness / g. Degrees of vagueness
We could make our intuitions about heaps precise with a million-valued logic [Fisher]
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
Vagueness can involve components (like baldness), or not (like boredom) [Fisher]
10. Modality / B. Possibility / 1. Possibility
We can't explain 'possibility' in terms of 'possible' worlds [Fisher]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
If all truths are implied by a falsehood, then not-p might imply both q and not-q [Fisher]
10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
In relevance logic, conditionals help information to flow from antecedent to consequent [Fisher]
19. Language / F. Communication / 1. Rhetoric
Rhetoric is irrational about its means and its ends [Plato]
Rhetoric can produce conviction, but not educate people about right and wrong [Plato]
20. Action / B. Preliminaries of Action / 1. Intention to Act / b. Types of intention
All activity aims at the good [Plato]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / g. Will to power
Moral rules are made by the weak members of humanity [Plato]
22. Metaethics / B. Value / 2. Values / h. Fine deeds
A good person is bound to act well, and this brings happiness [Plato]
22. Metaethics / B. Value / 2. Values / i. Self-interest
Is it natural to simply indulge our selfish desires? [Plato]
22. Metaethics / C. The Good / 1. Goodness / f. Good as pleasure
In slaking our thirst the goodness of the action and the pleasure are clearly separate [Plato]
Good should be the aim of pleasant activity, not the other way round [Plato]
22. Metaethics / C. The Good / 3. Pleasure / e. Role of pleasure
Good and bad people seem to experience equal amounts of pleasure and pain [Plato]
22. Metaethics / C. The Good / 3. Pleasure / f. Dangers of pleasure
If happiness is the satisfaction of desires, then a life of scratching itches should be happiness [Plato]
In a fool's mind desire is like a leaky jar, insatiable in its desires, and order and contentment are better [Plato]
23. Ethics / A. Egoism / 2. Hedonism
Is the happiest state one of sensual, self-indulgent freedom? [Plato]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / c. Motivation for virtue
Should we avoid evil because it will bring us bad consequences? [Plato]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / e. Character
I would rather be a victim of crime than a criminal [Plato]
23. Ethics / C. Virtue Theory / 3. Virtues / b. Temperance
Self-indulgent desire makes friendship impossible, because it makes a person incapable of co-operation [Plato]
If absence of desire is happiness, then nothing is happier than a stone or a corpse [Plato]
23. Ethics / C. Virtue Theory / 3. Virtues / c. Justice
A criminal is worse off if he avoids punishment [Plato]
Do most people praise self-discipline and justice because they are too timid to gain their own pleasure? [Plato]
23. Ethics / C. Virtue Theory / 4. External Goods / b. Health
The popular view is that health is first, good looks second, and honest wealth third [Plato]
24. Political Theory / B. Nature of a State / 1. Purpose of a State
As with other things, a good state is organised and orderly [Plato]
24. Political Theory / D. Ideologies / 5. Democracy / c. Direct democracy
A good citizen won't be passive, but will redirect the needs of the state [Plato]
25. Social Practice / B. Equalities / 1. Grounds of equality
Do most people like equality because they are second-rate? [Plato]
25. Social Practice / B. Equalities / 4. Economic equality
Does nature imply that it is right for better people to have greater benefits? [Plato]