35 ideas
| 8093 | Seek wisdom rather than truth; it is easier [Joubert] |
| 8095 | We must think with our entire body and soul [Joubert] |
| 8107 | The love of certainty holds us back in metaphysics [Joubert] |
| 8099 | The truths of reason instruct, but they do not illuminate [Joubert] |
| 8098 | Truth consists of having the same idea about something that God has [Joubert] |
| 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] |
| 17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki] |
| 17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
| 17757 | Members of ordinals are ordinals, and also subsets of ordinals [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] |
| 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] |
| 17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
| 8101 | To know is to see inside oneself [Joubert] |
| 8094 | The imagination has made more discoveries than the eye [Joubert] |
| 8103 | A thought is as real as a cannon ball [Joubert] |
| 8100 | Where does the bird's idea of a nest come from? [Joubert] |
| 8096 | He gives his body up to pleasure, but not his soul [Joubert] |
| 8104 | What will you think of pleasures when you no longer enjoy them? [Joubert] |
| 8097 | Virtue is hard if we are scorned; we need support [Joubert] |
| 8106 | In raising a child we must think of his old age [Joubert] |
| 5990 | Theophrastus doubted whether nature could be explained teleologically [Theophrastus, by Gottschalk] |
| 8105 | We can't exactly conceive virtue without the idea of God [Joubert] |
| 8102 | We cannot speak against Christianity without anger, or speak for it without love [Joubert] |