65 ideas
| 1695 | Without extensive examination firm statements are hard, but studying the difficulties is profitable [Aristotle] |
| 20771 | Six parts: dialectic, rhetoric, ethics, politics, physics, theology [Cleanthes, by Diog. Laertius] |
| 22270 | Frege changed philosophy by extending logic's ability to check the grounds of thinking [Potter on Frege] |
| 8939 | We should not describe human laws of thought, but how to correctly track truth [Frege, by Fisher] |
| 1698 | Both sides of contraries need not exist (as health without sickness, white without black) [Aristotle] |
| 1697 | The contrary of good is bad, but the contrary of bad is either good or another evil [Aristotle] |
| 11034 | The differentiae of genera which are different are themselves different in kind [Aristotle] |
| 18367 | A true existence statement has its truth caused by the existence of the thing [Aristotle] |
| 4971 | I don't use 'subject' and 'predicate' in my way of representing a judgement [Frege] |
| 17745 | For Frege, 'All A's are B's' means that the concept A implies the concept B [Frege, by Walicki] |
| 7728 | Frege has a judgement stroke (vertical, asserting or judging) and a content stroke (horizontal, expressing) [Frege, by Weiner] |
| 16881 | The laws of logic are boundless, so we want the few whose power contains the others [Frege] |
| 7622 | In 1879 Frege developed second order logic [Frege, by Putnam] |
| 11033 | Predications of predicates are predications of their subjects [Aristotle] |
| 7729 | Frege replaced Aristotle's subject/predicate form with function/argument form [Frege, by Weiner] |
| 9950 | A quantifier is a second-level predicate (which explains how it contributes to truth-conditions) [Frege, by George/Velleman] |
| 9991 | For Frege the variable ranges over all objects [Frege, by Tait] |
| 10536 | Frege's domain for variables is all objects, but modern interpretations first fix the domain [Dummett on Frege] |
| 7730 | Frege introduced quantifiers for generality [Frege, by Weiner] |
| 7742 | Frege reduced most quantifiers to 'everything' combined with 'not' [Frege, by McCullogh] |
| 13824 | Proof theory began with Frege's definition of derivability [Frege, by Prawitz] |
| 13609 | Frege produced axioms for logic, though that does not now seem the natural basis for logic [Frege, by Kaplan] |
| 11044 | One is prior to two, because its existence is implied by two [Aristotle] |
| 11042 | Parts of a line join at a point, so it is continuous [Aristotle] |
| 17855 | It may be possible to define induction in terms of the ancestral relation [Frege, by Wright,C] |
| 11041 | Some quantities are discrete, like number, and others continuous, like lines, time and space [Aristotle] |
| 10607 | Frege's logic has a hierarchy of object, property, property-of-property etc. [Frege, by Smith,P] |
| 11008 | Existence is not a first-order property, but the instantiation of a property [Frege, by Read] |
| 11286 | Primary being must be more than mere indeterminate ultimate subject of predication [Politis on Aristotle] |
| 1700 | There are six kinds of change: generation, destruction, increase, diminution, alteration, change of place [Aristotle] |
| 1699 | A thing is prior to another if it implies its existence [Aristotle] |
| 18366 | Of interdependent things, the prior one causes the other's existence [Aristotle] |
| 11035 | There are ten basic categories for thinking about things [Aristotle] |
| 3311 | The categories (substance, quality, quantity, relation, action, passion, place, time) peter out inconsequentially [Benardete,JA on Aristotle] |
| 13121 | Substance,Quantity,Quality,Relation,Place,Time,Being-in-a-position,Having,Doing,Being affected [Aristotle, by Westerhoff] |
| 16116 | Aristotle derived categories as answers to basic questions about nature, size, quality, location etc. [Aristotle, by Gill,ML] |
| 21345 | Aristotle said relations are not substances, so (if they exist) they must be accidents [Aristotle, by Heil] |
| 16155 | Aristotle promoted the importance of properties and objects (rather than general and particular) [Aristotle, by Frede,M] |
| 11032 | Some things said 'of' a subject are not 'in' the subject [Aristotle] |
| 11038 | We call them secondary 'substances' because they reveal the primary substances [Aristotle] |
| 16739 | Four species of quality: states, capacities, affects, and forms [Aristotle, by Pasnau] |
| 11037 | Colour must be in an individual body, or it is not embodied [Aristotle] |
| 16154 | Aristotle gave up his earlier notion of individuals, because it relied on universals [Aristotle, by Frede,M] |
| 12351 | Genus and species are substances, because only they reveal the primary substance [Aristotle, by Wedin] |
| 11040 | A single substance can receive contrary properties [Aristotle] |
| 1694 | Substances have no opposites, and don't come in degrees (including if the substance is a man) [Aristotle] |
| 16091 | Is primary substance just an ultimate subject, or some aspect of a complex body? [Aristotle, by Gill,ML] |
| 11280 | Primary being is 'that which lies under', or 'particular substance' [Aristotle, by Politis] |
| 11036 | A 'primary' substance is in each subject, with species or genera as 'secondary' substances [Aristotle] |
| 16140 | Secondary substances do have subjects, so they are not ultimate in the ontology [Aristotle, by Frede,M] |
| 10965 | In earlier Aristotle the substances were particulars, not kinds [Aristotle, by Lawson-Tancred] |
| 8287 | Earlier Aristotle had objects as primary substances, but later he switched to substantial form [Aristotle, by Lowe] |
| 12350 | Things are called 'substances' because they are subjects for everything else [Aristotle] |
| 11039 | A primary substance reveals a 'this', which is an individual unit [Aristotle] |
| 12361 | Primary substances are ontological in 'Categories', and explanatory in 'Metaphysics' [Aristotle, by Wedin] |
| 3315 | Aristotle denigrates the category of relation, but for modern absolutists self-relation is basic [Benardete,JA on Aristotle] |
| 6028 | Bodies interact with other bodies, and cuts cause pain, and shame causes blushing, so the soul is a body [Cleanthes, by Nemesius] |
| 20831 | The soul suffers when the body hurts, creates redness from shame, and pallor from fear [Cleanthes] |
| 12349 | Only what can be said of many things is a predicable [Aristotle, by Wedin] |
| 11837 | Some predicates signify qualification of a substance, others the substance itself [Aristotle] |
| 22280 | Frege's account was top-down and decompositional, not bottom-up and compositional [Frege, by Potter] |
| 11043 | It is not possible for fire to be cold or snow black [Aristotle] |
| 1696 | Change goes from possession to loss (as in baldness), but not the other way round [Aristotle] |
| 7741 | The predicate 'exists' is actually a natural language expression for a quantifier [Frege, by Weiner] |
| 5993 | The ascending scale of living creatures requires a perfect being [Cleanthes, by Tieleman] |