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] |
13832 | Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking] |
13007 | Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz] |
10067 | Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave] |
8326 | Science has shown that causal relations are just transfers of energy or momentum [Fair, by Sosa/Tooley] |
10379 | Fair shifted his view to talk of counterfactuals about energy flow [Fair, by Schaffer,J] |