36 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] |
| 10067 | Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave] |
| 17377 | All descriptive language is classificatory [Dupré] |
| 17376 | We should aim for a classification which tells us as much as possible about the object [Dupré] |
| 17390 | Natural kinds don't need essentialism to be explanatory [Dupré] |
| 17389 | A species might have its essential genetic mechanism replaced by a new one [Dupré] |
| 17388 | It seems that species lack essential properties, so they can't be natural kinds [Dupré] |
| 17374 | The possibility of prediction rests on determinism [Dupré] |
| 17378 | Presumably molecular structure seems important because we never have the Twin Earth experience [Dupré] |
| 23529 | Conduct is not isolated from its effect on the moral code [Hart,HLA] |
| 23530 | The great danger of democracy is that the oppression of the minority becomes unobjectionable [Hart,HLA] |
| 23522 | In an organised society all actions have some effect on other people [Hart,HLA] |
| 23528 | The value of liberty allows freedom of action, even if that distresses other people [Hart,HLA] |
| 21004 | Hart (against Bentham) says human rights are what motivate legal rights [Hart,HLA, by Sen] |
| 23523 | The principle of legality requires crimes to be precisely defined in advance of any action [Hart,HLA] |
| 23524 | Some private moral issues are no concern of the law [Hart,HLA] |
| 23521 | Do morals influence law? Is morality an aspect of law? Can law be morally criticised? [Hart,HLA] |
| 23525 | Is the enforcement of morality morally justifiable? [Hart,HLA] |
| 23526 | Modern law still suppresses practices seen as immoral, and yet harmless [Hart,HLA] |
| 20932 | Positive law needs secondary 'rules of recognition' for their correct application [Hart,HLA, by Zimmermann,J] |
| 20931 | Hart replaced positivism with the democratic requirement of the people's acceptance [Hart,HLA, by Zimmermann,J] |
| 23527 | Moral wickedness of an offence is always relevant to the degree of punishment [Hart,HLA] |
| 17381 | Phylogenetics involves history, and cladism rests species on splits in lineage [Dupré] |
| 17385 | Kinds don't do anything (including evolve) because they are abstract [Dupré] |
| 17375 | Natural kinds are decided entirely by the intentions of our classification [Dupré] |
| 17379 | Borders between species are much less clear in vegetables than among animals [Dupré] |
| 17384 | Even atoms of an element differ, in the energy levels of their electrons [Dupré] |
| 17387 | Ecologists favour classifying by niche, even though that can clash with genealogy [Dupré] |
| 17380 | Wales may count as fish [Dupré] |
| 17382 | Cooks, unlike scientists, distinguish garlic from onions [Dupré] |
| 17383 | Species are the lowest-level classification in biology [Dupré] |
| 17386 | The theory of evolution is mainly about species [Dupré] |