42 ideas
9136 | The paradox of analysis says that any conceptual analysis must be either trivial or false [Sorensen] |
9131 | Two long understandable sentences can have an unintelligible conjunction [Sorensen] |
10476 | The idea that groups of concepts could be 'implicitly defined' was abandoned [Hodges,W] |
9139 | If nothing exists, no truthmakers could make 'Nothing exists' true [Sorensen] |
9140 | Which toothbrush is the truthmaker for 'buy one, get one free'? [Sorensen] |
10282 | Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W] |
10478 | Since first-order languages are complete, |= and |- have the same meaning [Hodges,W] |
10477 | |= in model-theory means 'logical consequence' - it holds in all models [Hodges,W] |
9119 | No attempt to deny bivalence has ever been accepted [Sorensen] |
9135 | We now see that generalizations use variables rather than abstract entities [Sorensen] |
10283 | A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W] |
10284 | There are three different standard presentations of semantics [Hodges,W] |
10285 | I |= φ means that the formula φ is true in the interpretation I [Hodges,W] |
10474 | |= should be read as 'is a model for' or 'satisfies' [Hodges,W] |
10473 | Model theory studies formal or natural language-interpretation using set-theory [Hodges,W] |
10475 | A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W] |
10481 | Models in model theory are structures, not sets of descriptions [Hodges,W] |
10288 | Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W] |
10289 | Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W] |
10287 | If a first-order theory entails a sentence, there is a finite subset of the theory which entails it [Hodges,W] |
9125 | Denying problems, or being romantically defeated by them, won't make them go away [Sorensen] |
9137 | Banning self-reference would outlaw 'This very sentence is in English' [Sorensen] |
10480 | First-order logic can't discriminate between one infinite cardinal and another [Hodges,W] |
10286 | A 'set' is a mathematically well-behaved class [Hodges,W] |
9116 | Vague words have hidden boundaries [Sorensen] |
9132 | An offer of 'free coffee or juice' could slowly shift from exclusive 'or' to inclusive 'or' [Sorensen] |
19542 | It is nonsense that understanding does not involve knowledge; to understand, you must know [Dougherty/Rysiew] |
19543 | To grasp understanding, we should be more explicit about what needs to be known [Dougherty/Rysiew] |
19541 | Rather than knowledge, our epistemic aim may be mere true belief, or else understanding and wisdom [Dougherty/Rysiew] |
9128 | It is propositional attitudes which can be a priori, not the propositions themselves [Sorensen] |
9130 | Attributing apriority to a proposition is attributing a cognitive ability to someone [Sorensen] |
9118 | The colour bands of the spectrum arise from our biology; they do not exist in the physics [Sorensen] |
9124 | We are unable to perceive a nose (on the back of a mask) as concave [Sorensen] |
19540 | Don't confuse justified belief with justified believers [Dougherty/Rysiew] |
19539 | If knowledge is unanalysable, that makes justification more important [Dougherty/Rysiew] |
9126 | Bayesians build near-certainty from lots of reasonably probable beliefs [Sorensen] |
9121 | Illusions are not a reason for skepticism, but a source of interesting scientific information [Sorensen] |
9134 | The negation of a meaningful sentence must itself be meaningful [Sorensen] |
19538 | Entailment is modelled in formal semantics as set inclusion (where 'mammals' contains 'cats') [Dougherty/Rysiew] |
9133 | Propositions are what settle problems of ambiguity in sentences [Sorensen] |
9129 | I can buy any litre of water, but not every litre of water [Sorensen] |
9122 | God cannot experience unwanted pain, so God cannot understand human beings [Sorensen] |