30 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] |
17758 | Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [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] |
17757 | Members of ordinals are ordinals, and also subsets of ordinals [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] |
15201 | That Queen Anne is dead is a 'general fact', not a fact about Queen Anne [Prior,AN] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
7647 | The imagination alone perceives all objects; it is the soul, playing all its roles [La Mettrie] |
7645 | When falling asleep, the soul becomes paralysed and weak, just like the body [La Mettrie] |
23225 | The soul's faculties depend on the brain, and are simply the brain's organisation [La Mettrie] |
7652 | Man is a machine, and there exists only one substance, diversely modified [La Mettrie] |
7650 | All thought is feeling, and rationality is the sensitive soul contemplating reasoning [La Mettrie] |
7651 | With wonderful new machines being made, a speaking machine no longer seems impossible [La Mettrie] |
7648 | The sun and rain weren't made for us; they sometimes burn us, or spoil our seeds [La Mettrie] |
22899 | 'Thank goodness that's over' is not like 'thank goodness that happened on Friday' [Prior,AN] |
7646 | There is no abrupt transition from man to animal; only language has opened a gap [La Mettrie] |
7649 | There is no clear idea of the soul, which should only refer to our thinking part [La Mettrie] |