96 ideas
| 23350 | A wise philosophers uses reason to cautiously judge each aspect of living [Epictetus] |
| 23355 | The task of philosophy is to establish standards, as occurs with weights and measures [Epictetus] |
| 21394 | Philosophy is knowing each logos, how they fit together, and what follows from them [Epictetus] |
| 23367 | Even pointing a finger should only be done for a reason [Epictetus] |
| 20876 | Philosophy investigates the causes of disagreements, and seeks a standard for settling them [Epictetus] |
| 5750 | Consistency is modal, saying propositions are consistent if they could be true together [Melia] |
| 23344 | Reason itself must be compounded from some of our impressions [Epictetus] |
| 23343 | Because reason performs all analysis, we should analyse reason - but how? [Epictetus] |
| 5737 | Predicate logic has connectives, quantifiers, variables, predicates, equality, names and brackets [Melia] |
| 5744 | First-order predicate calculus is extensional logic, but quantified modal logic is intensional (hence dubious) [Melia] |
| 15413 | With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess] |
| 15415 | The temporal Barcan formulas fix what exists, which seems absurd [Burgess] |
| 15430 | Is classical logic a part of intuitionist logic, or vice versa? [Burgess] |
| 15431 | It is still unsettled whether standard intuitionist logic is complete [Burgess] |
| 15429 | Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess] |
| 15404 | Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess] |
| 15405 | Classical logic neglects the non-mathematical, such as temporality or modality [Burgess] |
| 15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess] |
| 15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
| 15403 | Philosophical logic is a branch of logic, and is now centred in computer science [Burgess] |
| 15407 | Formalising arguments favours lots of connectives; proving things favours having very few [Burgess] |
| 15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |
| 15409 | All occurrences of variables in atomic formulas are free [Burgess] |
| 15414 | The denotation of a definite description is flexible, rather than rigid [Burgess] |
| 5740 | Second-order logic needs second-order variables and quantification into predicate position [Melia] |
| 15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
| 15426 | We can build one expanding sequence, instead of a chain of deductions [Burgess] |
| 15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
| 15408 | 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess] |
| 15418 | Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess] |
| 15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
| 15412 | Models leave out meaning, and just focus on truth values [Burgess] |
| 5741 | If every model that makes premises true also makes conclusion true, the argument is valid [Melia] |
| 15416 | We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess] |
| 15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
| 10185 | Set theory is the standard background for modern mathematics [Burgess] |
| 10184 | Structuralists take the name 'R' of the reals to be a variable ranging over structures, not a structure [Burgess] |
| 10189 | There is no one relation for the real number 2, as relations differ in different models [Burgess] |
| 10186 | If set theory is used to define 'structure', we can't define set theory structurally [Burgess] |
| 10187 | Abstract algebra concerns relations between models, not common features of all the models [Burgess] |
| 10188 | How can mathematical relations be either internal, or external, or intrinsic? [Burgess] |
| 5736 | No sort of plain language or levels of logic can express modal facts properly [Melia] |
| 5735 | Maybe names and predicates can capture any fact [Melia] |
| 5746 | The Identity of Indiscernibles is contentious for qualities, and trivial for non-qualities [Melia] |
| 5738 | We may be sure that P is necessary, but is it necessarily necessary? [Melia] |
| 15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
| 5732 | 'De re' modality is about things themselves, 'de dicto' modality is about propositions [Melia] |
| 15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
| 15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
| 5739 | Sometimes we want to specify in what ways a thing is possible [Melia] |
| 15422 | Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess] |
| 15423 | It is doubtful whether the negation of a conditional has any clear meaning [Burgess] |
| 5734 | Possible worlds make it possible to define necessity and counterfactuals without new primitives [Melia] |
| 5742 | In possible worlds semantics the modal operators are treated as quantifiers [Melia] |
| 5743 | If possible worlds semantics is not realist about possible worlds, logic becomes merely formal [Melia] |
| 5749 | Possible worlds could be real as mathematics, propositions, properties, or like books [Melia] |
| 5751 | The truth of propositions at possible worlds are implied by the world, just as in books [Melia] |
| 23359 | We can't believe apparent falsehoods, or deny apparent truths [Epictetus] |
| 23356 | Self-evidence is most obvious when people who deny a proposition still have to use it [Epictetus] |
| 23330 | Freedom is making all things happen by choice, without constraint [Epictetus] |
| 23342 | Freedom is acting by choice, with no constraint possible [Epictetus] |
| 23329 | We make progress when we improve and naturalise our choices, asserting their freedom [Epictetus] |
| 23332 | Zeus gave me a nature which is free (like himself) from all compulsion [Epictetus] |
| 23331 | Not even Zeus can control what I choose [Epictetus] |
| 23338 | You can fetter my leg, but not even Zeus can control my power of choice [Epictetus] |
| 20875 | If we could foresee the future, we should collaborate with disease and death [Epictetus] |
| 23347 | If I know I am fated to be ill, I should want to be ill [Epictetus] |
| 5748 | We accept unverifiable propositions because of simplicity, utility, explanation and plausibility [Melia] |
| 23325 | Epictetus developed a notion of will as the source of our responsibility [Epictetus, by Frede,M] |
| 20873 | Tragedies are versified sufferings of people impressed by externals [Epictetus] |
| 23364 | Homer wrote to show that the most blessed men can be ruined by poor judgement [Epictetus] |
| 23340 | We consist of animal bodies and god-like reason [Epictetus] |
| 23366 | We see nature's will in the ways all people are the same [Epictetus] |
| 23358 | Every species produces exceptional beings, and we must just accept their nature [Epictetus] |
| 23339 | I will die as becomes a person returning what he does not own [Epictetus] |
| 23345 | Don't be frightened of pain or death; only be frightened of fearing them [Epictetus] |
| 23357 | Knowledge of what is good leads to love; only the wise, who distinguish good from evil, can love [Epictetus] |
| 23363 | The evil for everything is what is contrary to its nature [Epictetus] |
| 23328 | The essences of good and evil are in dispositions to choose [Epictetus] |
| 23362 | All human ills result from failure to apply preconceptions to particular cases [Epictetus] |
| 23353 | We have a natural sense of honour [Epictetus] |
| 23354 | If someone harms themselves in harming me, then I harm myself by returning the harm [Epictetus] |
| 23324 | In the Discourses choice [prohairesis] defines our character and behaviour [Epictetus, by Frede,M] |
| 4022 | Epictetus says we should console others for misfortune, but not be moved by pity [Epictetus, by Taylor,C] |
| 23365 | If someone is weeping, you should sympathise and help, but not share his suffering [Epictetus] |
| 23361 | Health is only a good when it is used well [Epictetus] |
| 23346 | A person is as naturally a part of a city as a foot is part of the body [Epictetus] |
| 23351 | We are citizens of the universe, and principal parts of it [Epictetus] |
| 23352 | A citizen should only consider what is good for the whole society [Epictetus] |
| 20874 | A citizen is committed to ignore private advantage, and seek communal good [Epictetus] |
| 22604 | Punishing a criminal for moral ignorance is the same as punishing someone for being blind [Epictetus] |
| 23368 | Perhaps we should persuade culprits that their punishment is just? [Epictetus] |
| 23349 | Asses are born to carry human burdens, not as ends in themselves [Epictetus] |
| 23341 | God created humans as spectators and interpreters of God's works [Epictetus] |
| 23348 | Both god and the good bring benefits, so their true nature seems to be the same [Epictetus] |
| 23360 | Each of the four elements in you is entirely scattered after death [Epictetus] |