11 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] |
18284 | Particulars can be verified or falsified, but general statements can only be falsified (conclusively) [Popper] |
21733 | The right-wing conception of freedom is based on the idea of self-ownership [Cohen,GA] |
21739 | Plenty of people have self-ownership, but still lack autonomy [Cohen,GA] |
21736 | It is doubtful whether any private property was originally acquired legitimately [Cohen,GA] |
21734 | It is plausible that no one has an initial right to own land and natural resources [Cohen,GA] |
21735 | Every thing which is now private started out as unowned [Cohen,GA] |