23 ideas
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] |
11976 | Aristotelian essentialism says essences are not relative to specification [Lewis] |
11978 | Causal necessities hold in all worlds compatible with the laws of nature [Lewis] |
11979 | It doesn't take the whole of a possible Humphrey to win the election [Lewis] |
16994 | Counterpart theory is bizarre, as no one cares what happens to a mere counterpart [Kripke on Lewis] |
11974 | Counterparts are not the original thing, but resemble it more than other things do [Lewis] |
11975 | If the closest resembler to you is in fact quite unlike you, then you have no counterpart [Lewis] |
11977 | Essential attributes are those shared with all the counterparts [Lewis] |
4058 | Is someone's right to life diminished if they were conceived by a rape? [Thomson] |
4060 | The right to life does not bestow the right to use someone else's body to support that life [Thomson] |
4062 | No one is morally required to make huge sacrifices to keep someone else alive for nine months [Thomson] |
4061 | The right to life is not a right not to be killed, but not to be killed unjustly [Thomson] |
4057 | A newly fertilized ovum is no more a person than an acorn is an oak tree [Thomson] |
4695 | Maybe abortion can be justified despite the foetus having full human rights [Thomson, by Foot] |
4059 | It can't be murder for a mother to perform an abortion on herself to save her own life [Thomson] |
4696 | The foetus is safe in the womb, so abortion initiates its death, with the mother as the agent. [Foot on Thomson] |