55 ideas
3656 | The greatest good for a state is true philosophers [Descartes] |
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] |
9718 | Validity is either semantic (what preserves truth), or proof-theoretic (following procedures) [Enderton] |
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] |
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] |
16744 | All powers can be explained by obvious features like size, shape and motion of matter [Descartes] |
5016 | Five universals: genus, species, difference, property, accident [Descartes] |
5015 | A universal is a single idea applied to individual things that are similar to one another [Descartes] |
16630 | If we perceive an attribute, we infer the existence of some substance [Descartes] |
5013 | A substance needs nothing else in order to exist [Descartes] |
16633 | A substance has one principal property which is its nature and essence [Descartes] |
9723 | Sentences with 'if' are only conditionals if they can read as A-implies-B [Enderton] |
3658 | Total doubt can't include your existence while doubting [Descartes] |
5005 | I think, therefore I am, because for a thinking thing to not exist is a contradiction [Descartes] |
5006 | 'Thought' is all our conscious awareness, including feeling as well as understanding [Descartes] |
5012 | 'Nothing comes from nothing' is an eternal truth found within the mind [Descartes] |
5004 | We can know basic Principles without further knowledge, but not the other way round [Descartes] |
5014 | We can understand thinking occuring without imagination or sensation [Descartes] |
5017 | In thinking we shut ourselves off from other substances, showing our identity and separateness [Descartes] |
5010 | Our free will is so self-evident to us that it must be a basic innate idea [Descartes] |
5011 | There are two ultimate classes of existence: thinking substance and extended substance [Descartes] |
5018 | Even if tightly united, mind and body are different, as God could separate them [Descartes] |
5007 | Most errors of judgement result from an inaccurate perception of the facts [Descartes] |
5009 | We do not praise the acts of an efficient automaton, as their acts are necessary [Descartes] |
5008 | The greatest perfection of man is to act by free will, and thus merit praise or blame [Descartes] |
15987 | Physics only needs geometry or abstract mathematics, which can explain and demonstrate everything [Descartes] |
12730 | We will not try to understand natural or divine ends, or final causes [Descartes] |
16601 | Matter is not hard, heavy or coloured, but merely extended in space [Descartes] |
16713 | Philosophers are the forefathers of heretics [Tertullian] |
6610 | I believe because it is absurd [Tertullian] |