4 ideas
3299 | In logic identity involves reflexivity (x=x), symmetry (if x=y, then y=x) and transitivity (if x=y and y=z, then x=z) [Baillie] |
17813 | Löwenheim-Skolem says any theory with a true interpretation has a model in the natural numbers [White,NP] |
17812 | Finite cardinalities don't need numbers as objects; numerical quantifiers will do [White,NP] |
1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |