62 ideas
3656 | The greatest good for a state is true philosophers [Descartes] |
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] |
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] |
16744 | All powers can be explained by obvious features like size, shape and motion of matter [Descartes] |
5016 | Five universals: genus, species, difference, property, accident [Descartes] |
5015 | A universal is a single idea applied to individual things that are similar to one another [Descartes] |
16630 | If we perceive an attribute, we infer the existence of some substance [Descartes] |
5013 | A substance needs nothing else in order to exist [Descartes] |
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] |
16633 | A substance has one principal property which is its nature and essence [Descartes] |
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] |
3658 | Total doubt can't include your existence while doubting [Descartes] |
5005 | I think, therefore I am, because for a thinking thing to not exist is a contradiction [Descartes] |
5006 | 'Thought' is all our conscious awareness, including feeling as well as understanding [Descartes] |
5012 | 'Nothing comes from nothing' is an eternal truth found within the mind [Descartes] |
18820 | In English 'evidence' is a mass term, qualified by 'little' and 'more' [Rumfitt] |
5004 | We can know basic Principles without further knowledge, but not the other way round [Descartes] |
5014 | We can understand thinking occuring without imagination or sensation [Descartes] |
5017 | In thinking we shut ourselves off from other substances, showing our identity and separateness [Descartes] |
5010 | Our free will is so self-evident to us that it must be a basic innate idea [Descartes] |
5011 | There are two ultimate classes of existence: thinking substance and extended substance [Descartes] |
5018 | Even if tightly united, mind and body are different, as God could separate them [Descartes] |
5007 | Most errors of judgement result from an inaccurate perception of the facts [Descartes] |
18817 | We understand conditionals, but disagree over their truth-conditions [Rumfitt] |
18829 | The truth grounds for 'not A' are the possibilities incompatible with truth grounds for A [Rumfitt] |
5009 | We do not praise the acts of an efficient automaton, as their acts are necessary [Descartes] |
5008 | The greatest perfection of man is to act by free will, and thus merit praise or blame [Descartes] |
15987 | Physics only needs geometry or abstract mathematics, which can explain and demonstrate everything [Descartes] |
12730 | We will not try to understand natural or divine ends, or final causes [Descartes] |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
16601 | Matter is not hard, heavy or coloured, but merely extended in space [Descartes] |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |