16 ideas
| 13201 | ∈ says the whole set is in the other; ⊆ says the members of the subset are in the other [Enderton] |
| 13206 | A 'linear or total ordering' must be transitive and satisfy trichotomy [Enderton] |
| 13204 | The 'ordered pair' <x,y> is defined to be {{x}, {x,y}} [Enderton] |
| 13200 | Note that {Φ} =/= Φ, because Φ ∈ {Φ} but Φ ∉ Φ [Enderton] |
| 13199 | The empty set may look pointless, but many sets can be constructed from it [Enderton] |
| 13203 | The singleton is defined using the pairing axiom (as {x,x}) [Enderton] |
| 13202 | Fraenkel added Replacement, to give a theory of ordinal numbers [Enderton] |
| 13205 | We can only define functions if Choice tells us which items are involved [Enderton] |
| 14082 | No sortal could ever exactly pin down which set of particles count as this 'cup' [Schaffer,J] |
| 14081 | Identities can be true despite indeterminate reference, if true under all interpretations [Schaffer,J] |
| 20725 | The idea of duty in one's calling haunts us, like a lost religion [Weber] |
| 20722 | Acquisition and low consumption lead to saving, investment, and increased wealth [Weber] |
| 20724 | When asceticism emerged from the monasteries, it helped to drive the modern economy [Weber] |
| 20717 | Capitalism is not unlimited greed, and may even be opposed to greed [Weber] |
| 20718 | Modern western capitalism has free labour, business separate from household, and book-keeping [Weber] |
| 20719 | Punish the heretic, but be indulgent to the sinner [Weber] |