14 ideas
13206 | A 'linear or total ordering' must be transitive and satisfy trichotomy [Enderton] |
13201 | ∈ says the whole set is in the other; ⊆ says the members of the subset are in the other [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] |
19398 | Minds are best explained by their ends, and bodies by efficient causes [Leibniz] |
13195 | To explain a house we must describe its use, as well as its parts [Leibniz] |
13193 | Active force is not just potential for action, since it involves a real effort or striving [Leibniz] |
13194 | God's laws would be meaningless without internal powers for following them [Leibniz] |
13196 | All qualities of bodies reduce to forces [Leibniz] |
13192 | Power is passive force, which is mass, and active force, which is entelechy or form [Leibniz] |