54 ideas
| 18730 | The history of philosophy only matters if the subject is a choice between rival theories [Wittgenstein] |
| 18704 | Philosophy tries to be rid of certain intellectual puzzles, irrelevant to daily life [Wittgenstein] |
| 18710 | Philosophers express puzzlement, but don't clearly state the puzzle [Wittgenstein] |
| 18732 | We don't need a theory of truth, because we use the word perfectly well [Wittgenstein] |
| 18714 | We already know what we want to know, and analysis gives us no new facts [Wittgenstein] |
| 18706 | Words of the same kind can be substituted in a proposition without producing nonsense [Wittgenstein] |
| 18735 | Talking nonsense is not following the rules [Wittgenstein] |
| 18719 | Grammar says that saying 'sound is red' is not false, but nonsense [Wittgenstein] |
| 18731 | There is no theory of truth, because it isn't a concept [Wittgenstein] |
| 18707 | All thought has the logical form of reality [Wittgenstein] |
| 10888 | Sets can be defined by 'enumeration', or by 'abstraction' (based on a property) [Zalabardo] |
| 10889 | The 'Cartesian Product' of two sets relates them by pairing every element with every element [Zalabardo] |
| 10890 | A 'partial ordering' is reflexive, antisymmetric and transitive [Zalabardo] |
| 10886 | Determinacy: an object is either in a set, or it isn't [Zalabardo] |
| 10887 | Specification: Determinate totals of objects always make a set [Zalabardo] |
| 18724 | In logic nothing is hidden [Wittgenstein] |
| 10897 | A first-order 'sentence' is a formula with no free variables [Zalabardo] |
| 10893 | Γ |= φ for sentences if φ is true when all of Γ is true [Zalabardo] |
| 10899 | Γ |= φ if φ is true when all of Γ is true, for all structures and interpretations [Zalabardo] |
| 18709 | Laws of logic are like laws of chess - if you change them, it's just a different game [Wittgenstein] |
| 18736 | Contradiction is between two rules, not between rule and reality [Wittgenstein] |
| 10896 | Propositional logic just needs ¬, and one of ∧, ∨ and → [Zalabardo] |
| 18723 | We may correctly use 'not' without making the rule explicit [Wittgenstein] |
| 18718 | Saying 'and' has meaning is just saying it works in a sentence [Wittgenstein] |
| 18727 | A person's name doesn't mean their body; bodies don't sit down, and their existence can be denied [Wittgenstein] |
| 10898 | The semantics shows how truth values depend on instantiations of properties and relations [Zalabardo] |
| 10902 | We can do semantics by looking at given propositions, or by building new ones [Zalabardo] |
| 10892 | We make a truth assignment to T and F, which may be true and false, but merely differ from one another [Zalabardo] |
| 10895 | 'Logically true' (|= φ) is true for every truth-assignment [Zalabardo] |
| 10900 | Logically true sentences are true in all structures [Zalabardo] |
| 10894 | A sentence-set is 'satisfiable' if at least one truth-assignment makes them all true [Zalabardo] |
| 10901 | Some formulas are 'satisfiable' if there is a structure and interpretation that makes them true [Zalabardo] |
| 10903 | A structure models a sentence if it is true in the model, and a set of sentences if they are all true in the model [Zalabardo] |
| 18738 | We don't get 'nearer' to something by adding decimals to 1.1412... (root-2) [Wittgenstein] |
| 18708 | Infinity is not a number, so doesn't say how many; it is the property of a law [Wittgenstein] |
| 10891 | If a set is defined by induction, then proof by induction can be applied to it [Zalabardo] |
| 18737 | There are no positive or negative facts; these are just the forms of propositions [Wittgenstein] |
| 18715 | Using 'green' is a commitment to future usage of 'green' [Wittgenstein] |
| 18726 | For each necessity in the world there is an arbitrary rule of language [Wittgenstein] |
| 18712 | Understanding is translation, into action or into other symbols [Wittgenstein] |
| 18280 | We live in sense-data, but talk about physical objects [Wittgenstein] |
| 18729 | Part of what we mean by stating the facts is the way we tend to experience them [Wittgenstein] |
| 18734 | If you remember wrongly, then there must be some other criterion than your remembering [Wittgenstein] |
| 18721 | Explanation and understanding are the same [Wittgenstein] |
| 18720 | Explanation gives understanding by revealing the full multiplicity of the thing [Wittgenstein] |
| 18716 | A machine strikes us as being a rule of movement [Wittgenstein] |
| 18713 | If an explanation is good, the symbol is used properly in the future [Wittgenstein] |
| 18717 | Thought is an activity which we perform by the expression of it [Wittgenstein] |
| 18725 | A proposition draws a line around the facts which agree with it [Wittgenstein] |
| 18728 | The meaning of a proposition is the mode of its verification [Wittgenstein] |
| 18705 | Words function only in propositions, like levers in a machine [Wittgenstein] |
| 14080 | Are causal descriptions part of the causal theory of reference, or are they just metasemantic? [Kaplan, by Schaffer,J] |
| 18711 | A proposition is any expression which can be significantly negated [Wittgenstein] |
| 18733 | Laws of nature are an aspect of the phenomena, and are just our mode of description [Wittgenstein] |