43 ideas
7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
9358 | There are several logics, none of which will ever derive falsehoods from truth [Lewis,CI] |
9357 | Excluded middle is just our preference for a simplified dichotomy in experience [Lewis,CI] |
9364 | Names represent a uniformity in experience, or they name nothing [Lewis,CI] |
12154 | Are 'word token' and 'word type' different sorts of countable objects, or two ways of counting? [Geach, by Perry] |
10735 | Abstraction from objects won't reveal an operation's being performed 'so many times' [Geach] |
8780 | Attributes are functions, not objects; this distinguishes 'square of 2' from 'double of 2' [Geach] |
8969 | We should abandon absolute identity, confining it to within some category [Geach, by Hawthorne] |
16075 | Denial of absolute identity has drastic implications for logic, semantics and set theory [Wasserman on Geach] |
12152 | Identity is relative. One must not say things are 'the same', but 'the same A as' [Geach] |
16073 | Leibniz's Law is incomplete, since it includes a non-relativized identity predicate [Geach, by Wasserman] |
11910 | Being 'the same' is meaningless, unless we specify 'the same X' [Geach] |
11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
9362 | Necessary truths are those we will maintain no matter what [Lewis,CI] |
7803 | Modal logic began with translation difficulties for 'If...then' [Lewis,CI, by Girle] |
9365 | We can maintain a priori principles come what may, but we can also change them [Lewis,CI] |
21500 | We rely on memory for empirical beliefs because they mutually support one another [Lewis,CI] |
21501 | If we doubt memories we cannot assess our doubt, or what is being doubted [Lewis,CI] |
6556 | If anything is to be probable, then something must be certain [Lewis,CI] |
21498 | Congruents assertions increase the probability of each individual assertion in the set [Lewis,CI] |
8775 | A big flea is a small animal, so 'big' and 'small' cannot be acquired by abstraction [Geach] |
8776 | We cannot learn relations by abstraction, because their converse must be learned too [Geach] |
10732 | If concepts are just recognitional, then general judgements would be impossible [Geach] |
2567 | You can't define real mental states in terms of behaviour that never happens [Geach] |
2568 | Beliefs aren't tied to particular behaviours [Geach] |
5828 | Extension is the class of things, intension is the correct definition of the thing, and intension determines extension [Lewis,CI] |
8781 | The mind does not lift concepts from experience; it creates them, and then applies them [Geach] |
10731 | For abstractionists, concepts are capacities to recognise recurrent features of the world [Geach] |
8769 | If someone has aphasia but can still play chess, they clearly have concepts [Geach] |
9361 | We have to separate the mathematical from physical phenomena by abstraction [Lewis,CI] |
8770 | 'Abstractionism' is acquiring a concept by picking out one experience amongst a group [Geach] |
8771 | 'Or' and 'not' are not to be found in the sensible world, or even in the world of inner experience [Geach] |
8772 | We can't acquire number-concepts by extracting the number from the things being counted [Geach] |
8773 | Abstractionists can't explain counting, because it must precede experience of objects [Geach] |
8774 | The numbers don't exist in nature, so they cannot have been abstracted from there into our languages [Geach] |
8778 | Blind people can use colour words like 'red' perfectly intelligently [Geach] |
8777 | If 'black' and 'cat' can be used in the absence of such objects, how can such usage be abstracted? [Geach] |
8779 | We can form two different abstract concepts that apply to a single unified experience [Geach] |
10733 | The abstractionist cannot explain 'some' and 'not' [Geach] |
10734 | Only a judgement can distinguish 'striking' from 'being struck' [Geach] |
22489 | 'Good' is an attributive adjective like 'large', not predicative like 'red' [Geach, by Foot] |
9363 | Science seeks classification which will discover laws, essences, and predictions [Lewis,CI] |
1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |