48 ideas
1597 | Thales was the first western thinker to believe the arché was intelligible [Roochnik on Thales] |
4456 | Epistemological Ockham's Razor demands good reasons, but the ontological version says reality is simple [Moreland] |
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] |
17764 | Boolean connectives are interpreted as functions on the set {1,0} [Walicki] |
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] |
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] |
17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [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] |
17757 | Members of ordinals are ordinals, and also subsets of ordinals [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] |
4474 | Existence theories must match experience, possibility, logic and knowledge, and not be self-defeating [Moreland] |
4461 | Tropes are like Hume's 'impressions', conceived as real rather than as ideal [Moreland] |
4462 | A colour-trope cannot be simple (as required), because it is spread in space, and so it is complex [Moreland] |
4463 | In 'four colours were used in the decoration', colours appear to be universals, not tropes [Moreland] |
4453 | One realism is one-over-many, which may be the model/copy view, which has the Third Man problem [Moreland] |
4464 | Realists see properties as universals, which are single abstract entities which are multiply exemplifiable [Moreland] |
4451 | If properties are universals, what distinguishes two things which have identical properties? [Moreland] |
4450 | The traditional problem of universals centres on the "One over Many", which is the unity of natural classes [Moreland] |
4449 | Evidence for universals can be found in language, communication, natural laws, classification and ideals [Moreland] |
4454 | The One-In-Many view says universals have abstract existence, but exist in particulars [Moreland] |
4468 | How could 'being even', or 'being a father', or a musical interval, exist naturally in space? [Moreland] |
4452 | Maybe universals are real, if properties themselves have properties, and relate to other properties [Moreland] |
4467 | A naturalist and realist about universals is forced to say redness can be both moving and stationary [Moreland] |
4469 | There are spatial facts about red particulars, but not about redness itself [Moreland] |
4472 | Redness is independent of red things, can do without them, has its own properties, and has identity [Moreland] |
4459 | Moderate nominalism attempts to embrace the existence of properties while avoiding universals [Moreland] |
4458 | Unlike Class Nominalism, Resemblance Nominalism can distinguish natural from unnatural classes [Moreland] |
4457 | There can be predicates with no property, and there are properties with no predicate [Moreland] |
4471 | We should abandon the concept of a property since (unlike sets) their identity conditions are unclear [Moreland] |
4476 | Most philosophers think that the identity of indiscernibles is false [Moreland] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
3013 | Nothing is stronger than necessity, which rules everything [Thales, by Diog. Laertius] |
4460 | Abstractions are formed by the mind when it concentrates on some, but not all, the features of a thing [Moreland] |
4455 | It is always open to a philosopher to claim that some entity or other is unanalysable [Moreland] |
1494 | Thales said water is the first principle, perhaps from observing that food is moist [Thales, by Aristotle] |
1713 | Thales must have thought soul causes movement, since he thought magnets have soul [Thales, by Aristotle] |
4473 | 'Presentism' is the view that only the present moment exists [Moreland] |
1742 | Thales said the gods know our wrong thoughts as well as our evil actions [Thales, by Diog. Laertius] |