62 ideas
18835 | Logic doesn't have a metaphysical basis, but nor can logic give rise to the metaphysics [Rumfitt] |
14782 | Philosophy is an experimental science, resting on common experience [Peirce] |
14787 | Self-contradiction doesn't reveal impossibility; it is inductive impossibility which reveals self-contradiction [Peirce] |
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] |
14783 | Logic, unlike mathematics, is not hypothetical; it asserts categorical ends from hypothetical means [Peirce] |
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] |
14788 | Mathematics is close to logic, but is even more abstract [Peirce] |
16185 | Causality indicates which properties are real [Cartwright,N] |
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] |
14786 | Some logical possibility concerns single propositions, but there is also compatibility between propositions [Peirce] |
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] |
14789 | Experience is indeed our only source of knowledge, provided we include inner experience [Peirce] |
14785 | The world is one of experience, but experiences are always located among our ideas [Peirce] |
18820 | In English 'evidence' is a mass term, qualified by 'little' and 'more' [Rumfitt] |
16182 | Two main types of explanation are by causes, or by citing a theoretical framework [Cartwright,N] |
16184 | An explanation is a model that fits a theory and predicts the phenomenological laws [Cartwright,N] |
16167 | Laws get the facts wrong, and explanation rests on improvements and qualifications of laws [Cartwright,N] |
16169 | Laws apply to separate domains, but real explanations apply to intersecting domains [Cartwright,N] |
16176 | Covering-law explanation lets us explain storms by falling barometers [Cartwright,N] |
16177 | I disagree with the covering-law view that there is a law to cover every single case [Cartwright,N] |
16180 | You can't explain one quail's behaviour by just saying that all quails do it [Cartwright,N] |
16171 | The covering law view assumes that each phenomenon has a 'right' explanation [Cartwright,N] |
16183 | In science, best explanations have regularly turned out to be false [Cartwright,N] |
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] |
14784 | Ethics is the science of aims [Peirce] |
16175 | A cause won't increase the effect frequency if other causes keep interfering [Cartwright,N] |
6781 | There are fundamental explanatory laws (false!), and phenomenological laws (regularities) [Cartwright,N, by Bird] |
16166 | Laws of appearances are 'phenomenological'; laws of reality are 'theoretical' [Cartwright,N] |
16179 | Good organisation may not be true, and the truth may not organise very much [Cartwright,N] |
16170 | To get from facts to equations, we need a prepared descriptions suited to mathematics [Cartwright,N] |
16181 | Simple laws have quite different outcomes when they act in combinations [Cartwright,N] |
16178 | There are few laws for when one theory meets another [Cartwright,N] |