18755 | Validity is explained as truth in all models, because that relies on the logical terms |

18759 | Identity is invariant under arbitrary permutations, so it seems to be a logical term |

18751 | Natural language includes connectives like 'because' which are not truth-functional |

18761 | Second-order variables need to range over more than collections of first-order objects |

18753 | An ontologically secure semantics for predicate calculus relies on sets |

18754 | Logically valid sentences are analytic truths which are just true because of their logical words |

18757 | Soundness theorems are uninformative, because they rely on soundness in their proofs |

18760 | The culmination of Euclidean geometry was axioms that made all models isomorphic |

18762 | A maxim claims that if we are allowed to assert a sentence, that means it must be true |