34 ideas
17749 | Post proved the consistency of propositional logic in 1921 [Walicki] |
17765 | Propositional language can only relate statements as the same or as different [Walicki] |
17764 | Boolean connectives are interpreted as functions on the set {1,0} [Walicki] |
17752 | The empty set is useful for defining sets by properties, when the members are not yet known [Walicki] |
17753 | The empty set avoids having to take special precautions in case members vanish [Walicki] |
17759 | Ordinals play the central role in set theory, providing the model of well-ordering [Walicki] |
17741 | To determine the patterns in logic, one must identify its 'building blocks' [Walicki] |
17747 | A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki] |
17748 | The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki] |
17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki] |
17757 | Members of ordinals are ordinals, and also subsets of ordinals [Walicki] |
17755 | Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki] |
17756 | The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki] |
17760 | Two infinite ordinals can represent a single infinite cardinal [Walicki] |
17758 | Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki] |
17762 | In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki] |
17754 | Inductive proof depends on the choice of the ordering [Walicki] |
18890 | Putnam smuggles essentialism about liquids into his proof that water must be H2O [Salmon,N on Putnam] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
22868 | The value and truth of knowledge are measured by success in activity [Dewey] |
7705 | The Twin Earth theory suggests that intentionality is independent of qualia [Jacquette on Putnam] |
22865 | Habits constitute the self [Dewey] |
4099 | If Twins talking about 'water' and 'XYZ' have different thoughts but identical heads, then thoughts aren't in the head [Putnam, by Crane] |
12026 | We say ice and steam are different forms of water, but not that they are different forms of H2O [Forbes,G on Putnam] |
3208 | Does 'water' mean a particular substance that was 'dubbed'? [Putnam, by Rey] |
3893 | Often reference determines sense, and not (as Frege thought) vice versa [Putnam, by Scruton] |
22871 | The good people are those who improve; the bad are those who deteriorate [Dewey] |
22876 | Democracy is the development of human nature when it shares in the running of communal activities [Dewey] |
22875 | Democracy is not just a form of government; it is a mode of shared living [Dewey] |
22874 | Individuality is only developed within groups [Dewey] |
11191 | The hidden structure of a natural kind determines membership in all possible worlds [Putnam] |
11192 | If causes are the essence of diseases, then disease is an example of a relational essence [Putnam, by Williams,NE] |
11190 | Archimedes meant by 'gold' the hidden structure or essence of the stuff [Putnam] |