8 ideas
11022 | Gentzen introduced a natural deduction calculus (NK) in 1934 [Gentzen, by Read] |
11065 | The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna] |
11023 | The logical connectives are 'defined' by their introduction rules [Gentzen] |
11213 | Each logical symbol has an 'introduction' rule to define it, and hence an 'elimination' rule [Gentzen] |
10067 | Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave] |
8840 | There are five possible responses to the problem of infinite regress in justification [Cleve] |
8841 | Modern foundationalists say basic beliefs are fallible, and coherence is relevant [Cleve] |
22230 | Sartre gradually realised that freedom is curtailed by the weight of situation [Sartre, by Daigle] |