9 ideas
14238 | A class is an aggregate of objects; if you destroy them, you destroy the class; there is no empty class [Frege] |
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] |
22370 | Big central government only exists as a focus for anger - not to act [Fisher] |
22368 | It is hard to imagine the end of capitalism [Fisher] |
22369 | Are students consumers or products of education? [Fisher] |