52 ideas
18835 | Logic doesn't have a metaphysical basis, but nor can logic give rise to the metaphysics [Rumfitt] |
18819 | The idea that there are unrecognised truths is basic to our concept of truth [Rumfitt] |
18826 | 'True at a possibility' means necessarily true if what is said had obtained [Rumfitt] |
18803 | Semantics for propositions: 1) validity preserves truth 2) non-contradition 3) bivalence 4) truth tables [Rumfitt] |
18814 | 'Absolute necessity' would have to rest on S5 [Rumfitt] |
18798 | It is the second-order part of intuitionistic logic which actually negates some classical theorems [Rumfitt] |
18799 | Intuitionists can accept Double Negation Elimination for decidable propositions [Rumfitt] |
18830 | Most set theorists doubt bivalence for the Continuum Hypothesis, but still use classical logic [Rumfitt] |
18843 | The iterated conception of set requires continual increase in axiom strength [Rumfitt] |
18836 | A set may well not consist of its members; the empty set, for example, is a problem [Rumfitt] |
18837 | A set can be determinate, because of its concept, and still have vague membership [Rumfitt] |
18845 | If the totality of sets is not well-defined, there must be doubt about the Power Set Axiom [Rumfitt] |
18815 | Logic is higher-order laws which can expand the range of any sort of deduction [Rumfitt] |
18804 | The case for classical logic rests on its rules, much more than on the Principle of Bivalence [Rumfitt] |
18805 | Classical logic rules cannot be proved, but various lines of attack can be repelled [Rumfitt] |
18827 | If truth-tables specify the connectives, classical logic must rely on Bivalence [Rumfitt] |
18813 | Logical consequence is a relation that can extended into further statements [Rumfitt] |
18808 | Normal deduction presupposes the Cut Law [Rumfitt] |
18840 | When faced with vague statements, Bivalence is not a compelling principle [Rumfitt] |
18802 | In specifying a logical constant, use of that constant is quite unavoidable [Rumfitt] |
18800 | Introduction rules give deduction conditions, and Elimination says what can be deduced [Rumfitt] |
18809 | Logical truths are just the assumption-free by-products of logical rules [Rumfitt] |
18807 | Monotonicity means there is a guarantee, rather than mere inductive support [Rumfitt] |
13163 | Circles must be bounded, so cannot be infinite [Leibniz] |
18842 | Maybe an ordinal is a property of isomorphic well-ordered sets, and not itself a set [Rumfitt] |
18834 | Infinitesimals do not stand in a determinate order relation to zero [Rumfitt] |
18846 | Cantor and Dedekind aimed to give analysis a foundation in set theory (rather than geometry) [Rumfitt] |
18839 | An object that is not clearly red or orange can still be red-or-orange, which sweeps up problem cases [Rumfitt] |
18838 | The extension of a colour is decided by a concept's place in a network of contraries [Rumfitt] |
18816 | Metaphysical modalities respect the actual identities of things [Rumfitt] |
18825 | S5 is the logic of logical necessity [Rumfitt] |
18824 | Since possibilities are properties of the world, calling 'red' the determination of a determinable seems right [Rumfitt] |
18828 | If two possibilities can't share a determiner, they are incompatible [Rumfitt] |
18821 | Possibilities are like possible worlds, but not fully determinate or complete [Rumfitt] |
18831 | Medieval logicians said understanding A also involved understanding not-A [Rumfitt] |
19527 | We don't acquire evidence and then derive some knowledge, because evidence IS knowledge [Williamson] |
19528 | Knowledge is prior to believing, just as doing is prior to trying to do [Williamson] |
19529 | Belief explains justification, and knowledge explains belief, so knowledge explains justification [Williamson] |
19530 | A neutral state of experience, between error and knowledge, is not basic; the successful state is basic [Williamson] |
19531 | Internalism about mind is an obsolete view, and knowledge-first epistemology develops externalism [Williamson] |
19536 | Knowledge-first says your total evidence IS your knowledge [Williamson] |
19526 | Surely I am acquainted with physical objects, not with appearances? [Williamson] |
18820 | In English 'evidence' is a mass term, qualified by 'little' and 'more' [Rumfitt] |
13162 | Sloth's Syllogism: either it can't happen, or it is inevitable without my effort [Leibniz] |
18817 | We understand conditionals, but disagree over their truth-conditions [Rumfitt] |
19534 | How does inferentialism distinguish the patterns of inference that are essential to meaning? [Williamson] |
19535 | Internalist inferentialism has trouble explaining how meaning and reference relate [Williamson] |
19533 | Inferentialist semantics relies on internal inference relations, not on external references [Williamson] |
19532 | Truth-conditional referential semantics is externalist, referring to worldly items [Williamson] |
18829 | The truth grounds for 'not A' are the possibilities incompatible with truth grounds for A [Rumfitt] |
19339 | Evil is a negation of good, which arises from non-being [Leibniz] |
13164 | God only made sin possible because a much greater good can be derived from it [Leibniz] |