9 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] |
20752 | For man, being is not what he is, but what he is going to be [Ortega y Gassett] |
2614 | Modern phenomenalism holds that objects are logical constructions out of sense-data [Ayer] |
2615 | The concept of sense-data allows us to discuss appearances without worrying about reality [Ayer] |
20756 | Instead of having a nature, man only has a history [Ortega y Gassett] |