54 ideas
| 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] |
| 15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
| 15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [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] |
| 15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
| 15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
| 15426 | We can build one expanding sequence, instead of a chain of deductions [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] |
| 15412 | Models leave out meaning, and just focus on truth values [Burgess] |
| 15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
| 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] |
| 5311 | If observation goes up a level, we expect the laws of the lower level to remain in force [Wilson,EO] |
| 5312 | A child first sees objects as distinct, and later as members of groups [Wilson,EO] |
| 15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
| 15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
| 15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
| 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] |
| 5309 | Beliefs are really enabling mechanisms for survival [Wilson,EO] |
| 6685 | 'Subjectivism' is an extension of relativism from the social group to the individual [Graham] |
| 5310 | Philosophers study the consequences of ethics instead of its origins [Wilson,EO] |
| 6699 | The chain of consequences may not be the same as the chain of responsibility [Graham] |
| 5313 | The rules of human decision-making converge and overlap in a 'human nature' [Wilson,EO] |
| 5316 | We undermine altruism by rewarding it, but we reward it to encourage it [Wilson,EO] |
| 5318 | Pure hard-core altruism based on kin selection is the enemy of civilisation [Wilson,EO] |
| 6698 | Negative consequences are very hard (and possibly impossible) to assess [Graham] |
| 6700 | We can't criticise people because of unforeseeable consequences [Graham] |
| 6704 | Egoism submits to desires, but cannot help form them [Graham] |
| 5317 | The actor is most convincing who believes that his performance is real [Wilson,EO] |
| 6701 | Rescue operations need spontaneous benevolence, not careful thought [Graham] |
| 6693 | 'What if everybody did that?' rather misses the point as an objection to cheating [Graham] |
| 6691 | It is more plausible to say people can choose between values, than that they can create them [Graham] |
| 6688 | Life is only absurd if you expected an explanation and none turns up [Graham] |
| 6705 | Existentialism may transcend our nature, unlike eudaimonism [Graham] |
| 6690 | A standard problem for existentialism is the 'sincere Nazi' [Graham] |
| 6689 | The key to existentialism: the way you make choices is more important than what you choose [Graham] |
| 5308 | The only human purpose is that created by our genetic history [Wilson,EO] |
| 5314 | Cultural evolution is Lamarckian and fast, biological evolution is Darwinian and slow [Wilson,EO] |
| 5315 | Over 99 percent of human evolution has been in the hunter-gatherer phase [Wilson,EO] |
| 5320 | It is estimated that mankind has produced 100,000 religions [Wilson,EO] |
| 6706 | The great religions are much more concerned with the religious life than with ethics [Graham] |
| 6709 | Western religion saves us from death; Eastern religion saves us from immortality [Graham] |