107 ideas
11283 | There is pure deductive reasoning, and explanatory demonstration reasoning [Aristotle, by Politis] |
1672 | Maybe everything could be demonstrated, if demonstration can be reciprocal or circular [Aristotle] |
1684 | Two falsehoods can be contrary to one another [Aristotle] |
6806 | Do not multiply entities beyond necessity [William of Ockham] |
12145 | Definitions are of what something is, and that is universal [Aristotle] |
12075 | An Aristotelian definition is causal [Aristotle, by Witt] |
12384 | Definition by division needs predicates, which are well ordered and thorough [Aristotle] |
9066 | You can define objects by progressively identifying what is the same and what is different [Aristotle] |
12382 | What it is and why it is are the same; screening defines and explains an eclipse [Aristotle] |
1668 | An axiom is a principle which must be understood if one is to learn anything [Aristotle] |
9724 | Until the 1960s the only semantics was truth-tables [Enderton] |
9703 | 'dom R' indicates the 'domain' of objects having a relation [Enderton] |
9705 | 'fld R' indicates the 'field' of all objects in the relation [Enderton] |
9704 | 'ran R' indicates the 'range' of objects being related to [Enderton] |
9710 | We write F:A→B to indicate that A maps into B (the output of F on A is in B) [Enderton] |
9707 | 'F(x)' is the unique value which F assumes for a value of x [Enderton] |
9712 | A relation is 'symmetric' on a set if every ordered pair has the relation in both directions [Enderton] |
9713 | A relation is 'transitive' if it can be carried over from two ordered pairs to a third [Enderton] |
9699 | The 'powerset' of a set is all the subsets of a given set [Enderton] |
9700 | Two sets are 'disjoint' iff their intersection is empty [Enderton] |
9702 | A 'domain' of a relation is the set of members of ordered pairs in the relation [Enderton] |
9701 | A 'relation' is a set of ordered pairs [Enderton] |
9706 | A 'function' is a relation in which each object is related to just one other object [Enderton] |
9708 | A function 'maps A into B' if the relating things are set A, and the things related to are all in B [Enderton] |
9709 | A function 'maps A onto B' if the relating things are set A, and the things related to are set B [Enderton] |
9711 | A relation is 'reflexive' on a set if every member bears the relation to itself [Enderton] |
9714 | A relation satisfies 'trichotomy' if all pairs are either relations, or contain identical objects [Enderton] |
9717 | A set is 'dominated' by another if a one-to-one function maps the first set into a subset of the second [Enderton] |
9715 | An 'equivalence relation' is a reflexive, symmetric and transitive binary relation [Enderton] |
9716 | We 'partition' a set into distinct subsets, according to each relation on its objects [Enderton] |
9722 | Inference not from content, but from the fact that it was said, is 'conversational implicature' [Enderton] |
12376 | Demonstrations by reductio assume excluded middle [Aristotle] |
12373 | Something holds universally when it is proved of an arbitrary and primitive case [Aristotle] |
9718 | Validity is either semantic (what preserves truth), or proof-theoretic (following procedures) [Enderton] |
12363 | Everything is either asserted or denied truly [Aristotle] |
9721 | A logical truth or tautology is a logical consequence of the empty set [Enderton] |
9994 | A truth assignment to the components of a wff 'satisfy' it if the wff is then True [Enderton] |
13004 | Aristotle's axioms (unlike Euclid's) are assumptions awaiting proof [Aristotle, by Leibniz] |
9719 | A proof theory is 'sound' if its valid inferences entail semantic validity [Enderton] |
9720 | A proof theory is 'complete' if semantically valid inferences entail proof-theoretic validity [Enderton] |
9995 | Proof in finite subsets is sufficient for proof in an infinite set [Enderton] |
9996 | Expressions are 'decidable' if inclusion in them (or not) can be proved [Enderton] |
9997 | For a reasonable language, the set of valid wff's can always be enumerated [Enderton] |
12377 | Mathematics is concerned with forms, not with superficial properties [Aristotle] |
12372 | The essence of a triangle comes from the line, mentioned in any account of triangles [Aristotle] |
12369 | A unit is what is quantitatively indivisible [Aristotle] |
18910 | To seek truth, study the real connections between subjects and attributes [Aristotle] |
1675 | Separate Forms aren't needed for logic, but universals (one holding of many) are essential [Aristotle] |
22132 | Species and genera are individual concepts which naturally signify many individuals [William of Ockham] |
1677 | We can forget the Forms, as they are irrelevant, and not needed in giving demonstrations [Aristotle] |
1687 | Why are being terrestrial and a biped combined in the definition of man, but being literate and musical aren't? [Aristotle] |
1681 | Units are positionless substances, and points are substances with position [Aristotle] |
12146 | Definitions recognise essences, so are not themselves essences [Aristotle] |
17039 | The predicates of a thing's nature are necessary to it [Aristotle] |
11994 | Aristotelian essences are properties mentioned at the starting point of a science [Aristotle, by Kung] |
12381 | What is necessary cannot be otherwise [Aristotle] |
1690 | A stone travels upwards by a forced necessity, and downwards by natural necessity [Aristotle] |
9723 | Sentences with 'if' are only conditionals if they can read as A-implies-B [Enderton] |
12072 | For Aristotle knowledge is explanatory, involving understanding, and principles or causes [Aristotle, by Witt] |
12073 | 'Episteme' means grasping causes, universal judgments, explanation, and teaching [Aristotle, by Witt] |
12378 | The reason why is the key to knowledge [Aristotle] |
12364 | We understand a thing when we know its explanation and its necessity [Aristotle] |
12366 | We only understand something when we know its explanation [Aristotle] |
12370 | Some understanding, of immediate items, is indemonstrable [Aristotle] |
1685 | No one has mere belief about something if they think it HAS to be true [Aristotle] |
1673 | Knowledge proceeds from principles, so it is hard to know if we know [Aristotle] |
12379 | You cannot understand anything through perception [Aristotle] |
16725 | Some knowledge is lost if you lose a sense, and there is no way the knowledge can be replaced [Aristotle] |
23309 | Aristotle's concepts of understanding and explanation mean he is not a pure empiricist [Aristotle, by Frede,M] |
1693 | Animals may have some knowledge if they retain perception, but understanding requires reasons to be given [Aristotle] |
9067 | Many memories of the same item form a single experience [Aristotle] |
1671 | Sceptics say justification is an infinite regress, or it stops at the unknowable [Aristotle] |
1670 | When you understand basics, you can't be persuaded to change your mind [Aristotle] |
1691 | Aim to get definitions of the primitive components, thus establishing the kind, and work towards the attributes [Aristotle] |
12383 | There must be definitions before demonstration is possible [Aristotle] |
1674 | All demonstration is concerned with existence, axioms and properties [Aristotle] |
24068 | Demonstration is more than entailment, as the explanatory order must match the causal order [Aristotle, by Koslicki] |
17310 | Aristotle gets asymmetric consequence from demonstration, which reflects real causal priority [Aristotle, by Koslicki] |
21359 | Aristotle doesn't actually apply his theory of demonstration to his practical science [Leroi on Aristotle] |
1667 | Premises must be true, primitive and immediate, and prior to and explanatory of conclusions [Aristotle] |
12365 | We can know by demonstration, which is a scientific deduction leading to understanding [Aristotle] |
10918 | Demonstrative understanding rests on necessary features of the thing in itself [Aristotle] |
12374 | Demonstrations must be necessary, and that depends on the middle term [Aristotle] |
12148 | Demonstrations are syllogisms which give explanations [Aristotle] |
1679 | Universal demonstrations are about thought; particular demonstrations lead to perceptions [Aristotle] |
1680 | Demonstration is better with fewer presuppositions, and it is quicker if these are familiar [Aristotle] |
12147 | The principles of demonstrations are definitions [Aristotle] |
12371 | A demonstration is a deduction which proceeds from necessities [Aristotle] |
1683 | We learn universals from many particulars [Aristotle] |
12367 | What is most universal is furthest away, and the particulars are nearest [Aristotle] |
12380 | Universals are valuable because they make the explanations plain [Aristotle] |
12385 | Are particulars explained more by universals, or by other particulars? [Aristotle] |
1689 | Explanation is of the status of a thing, inferences to it, initiation of change, and purpose [Aristotle] |
1686 | What we seek and understand are facts, reasons, existence, and identity [Aristotle] |
12357 | Explanation and generality are inseparable [Aristotle, by Wedin] |
1669 | The foundation or source is stronger than the thing it causes [Aristotle] |
1678 | Universals give better explanations, because they are self-explanatory and primitive [Aristotle] |
9068 | Perception creates primitive immediate principles by building a series of firm concepts [Aristotle] |
9069 | A perception lodging in the soul creates a primitive universal, which becomes generalised [Aristotle] |
9070 | We learn primitives and universals by induction from perceptions [Aristotle] |
12368 | Negation takes something away from something [Aristotle] |
1692 | If you shouldn't argue in metaphors, then you shouldn't try to define them either [Aristotle] |
12375 | Whatever holds of a kind intrinsically holds of it necessarily [Aristotle] |
19381 | The past has ceased to exist, and the future does not yet exist, so time does not exist [William of Ockham] |
8010 | William of Ockham is the main spokesman for God's commands being the source of morality [William of Ockham] |
1688 | Properties must be proved, but not essence; but existents are not a kind, so existence isn't part of essence [Aristotle] |
16679 | Even an angel must have some location [William of Ockham, by Pasnau] |