31 ideas
22438 | Philosophy is largely concerned with finding the minimum that science could get by with [Quine] |
22436 | Logicians don't paraphrase logic into language, because they think in the symbolic language [Quine] |
22431 | Good algorithms and theories need many occurrences of just a few elements [Quine] |
17749 | Post proved the consistency of propositional logic in 1921 [Walicki] |
17765 | Propositional language can only relate statements as the same or as different [Walicki] |
22435 | The logician's '→' does not mean the English if-then [Quine] |
17764 | Boolean connectives are interpreted as functions on the set {1,0} [Walicki] |
22433 | It is important that the quantification over temporal entities is timeless [Quine] |
17752 | The empty set is useful for defining sets by properties, when the members are not yet known [Walicki] |
17753 | The empty set avoids having to take special precautions in case members vanish [Walicki] |
17759 | Ordinals play the central role in set theory, providing the model of well-ordering [Walicki] |
17741 | To determine the patterns in logic, one must identify its 'building blocks' [Walicki] |
22437 | Logical languages are rooted in ordinary language, and that connection must be kept [Quine] |
22434 | Reduction to logical forms first simplifies idioms and grammar, then finds a single reading of it [Quine] |
17747 | A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki] |
17748 | The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki] |
17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki] |
17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
17757 | Members of ordinals are ordinals, and also subsets of ordinals [Walicki] |
17758 | Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki] |
17755 | Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki] |
17756 | The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki] |
17760 | Two infinite ordinals can represent a single infinite cardinal [Walicki] |
17762 | In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki] |
17754 | Inductive proof depends on the choice of the ordering [Walicki] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
22432 | Normally conditionals have no truth value; it is the consequent which has a conditional truth value [Quine] |
22363 | You have only begun to do real science when you can express it in numbers [Kelvin] |
22430 | If we understand a statement, we know the circumstances of its truth [Quine] |
20644 | Energy has progressed from a mere formula, to a principle pervading all nature [Kelvin] |
13713 | Quine holds time to be 'space-like': past objects are as real as spatially remote ones [Quine, by Sider] |