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] |
19525 | If the only aim is to believe truths, that justifies recklessly believing what is unsupported (if it is right) [Conee/Feldman] |
19524 | We don't have the capacity to know all the logical consequences of our beliefs [Conee/Feldman] |
18284 | Particulars can be verified or falsified, but general statements can only be falsified (conclusively) [Popper] |