32 ideas
7823 | Lucretius was rediscovered in 1417 [Grayling] |
4037 | Ockham's Razor is the principle that we need reasons to believe in entities [Mellor/Oliver] |
13913 | The four 'perfect syllogisms' are called Barbara, Celarent, Darii and Ferio [Engelbretsen/Sayward] |
13914 | Syllogistic logic has one rule: what is affirmed/denied of wholes is affirmed/denied of their parts [Engelbretsen/Sayward] |
13915 | Syllogistic can't handle sentences with singular terms, or relational terms, or compound sentences [Engelbretsen/Sayward] |
13916 | Term logic uses expression letters and brackets, and '-' for negative terms, and '+' for compound terms [Engelbretsen/Sayward] |
13850 | In modern logic all formal validity can be characterised syntactically [Engelbretsen/Sayward] |
13849 | Classical logic rests on truth and models, where constructivist logic rests on defence and refutation [Engelbretsen/Sayward] |
13851 | Unlike most other signs, = cannot be eliminated [Engelbretsen/Sayward] |
13852 | Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward] |
6408 | Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling] |
4027 | Properties are respects in which particular objects may be alike or differ [Mellor/Oliver] |
4029 | Nominalists ask why we should postulate properties at all [Mellor/Oliver] |
6414 | Two propositions might seem self-evident, but contradict one another [Grayling] |
7091 | The argument from analogy is not a strong inference, since the other being might be an actor or a robot [Grayling] |
4039 | Abstractions lack causes, effects and spatio-temporal locations [Mellor/Oliver] |
7293 | It is legitimate to do harm if it is the unintended side-effect of an effort to achieve a good [Grayling] |
7809 | In an honour code shame is the supreme punishment, and revenge is a duty [Grayling] |
23262 | Experience, sympathy and history are sensible grounds for laying claim to rights [Grayling] |
23263 | Politics is driven by power cliques [Grayling] |
23255 | It is essential for democracy that voting is free and well informed [Grayling] |
23254 | Democracies should require a supermajority for major questions [Grayling] |
23260 | A cap on time of service would restrict party control and career ambitions [Grayling] |
23253 | Majority decisions are only acceptable if the minority interests are not vital [Grayling] |
23256 | Liberty and equality cannot be reconciled [Grayling] |
23258 | The very concept of democracy entails a need for justice [Grayling] |
23259 | There should be separate legislative, executive and judicial institutions [Grayling] |
7292 | War must also have a good chance of success, and be waged with moderation [Grayling] |
7824 | If suicide is lawful, but assisting suicide is unlawful, powerless people are denied their rights [Grayling] |
7819 | Religion gives answers, comforts, creates social order, and panders to superstition [Grayling] |
7817 | To make an afterlife appealing, this life has to be denigrated [Grayling] |
7818 | In Greek mythology only heroes can go to heaven [Grayling] |