56 ideas
5196 | Philosophy is a department of logic [Ayer] |
5189 | Philosophers should abandon speculation, as philosophy is wholly critical [Ayer] |
7919 | Humeans rejected the a priori synthetic, and so rejected even Kantian metaphysics [Ayer, by Macdonald,C] |
5195 | Critics say analysis can only show the parts, and not their distinctive configuration [Ayer] |
5179 | Philosophy deals with the questions that scientists do not wish to handle [Ayer] |
4749 | We cannot analyse the concept of 'truth', because it is simply a mark that a sentence is asserted [Ayer] |
10751 | Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg] |
10757 | Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg] |
10759 | There are at least seven possible systems of semantics for second-order logic [Rossberg] |
10753 | Logical consequence is intuitively semantic, and captured by model theory [Rossberg] |
10752 | Γ |- S says S can be deduced from Γ; Γ |= S says a good model for Γ makes S true [Rossberg] |
10754 | In proof-theory, logical form is shown by the logical constants [Rossberg] |
10756 | A model is a domain, and an interpretation assigning objects, predicates, relations etc. [Rossberg] |
10758 | If models of a mathematical theory are all isomorphic, it is 'categorical', with essentially one model [Rossberg] |
10761 | Completeness can always be achieved by cunning model-design [Rossberg] |
10755 | A deductive system is only incomplete with respect to a formal semantics [Rossberg] |
5202 | Maths and logic are true universally because they are analytic or tautological [Ayer] |
6523 | Positivists regard ontology as either meaningless or stipulated [Ayer, by Robinson,H] |
5183 | Only tautologies can be certain; other propositions can only be probable [Ayer] |
6525 | Logical positivists could never give the sense-data equivalent of 'there is a table next door' [Robinson,H on Ayer] |
5170 | Material things are constructions from actual and possible occurrences of sense-contents [Ayer] |
5198 | We could verify 'a thing can't be in two places at once' by destroying one of the things [Ierubino on Ayer] |
2619 | Whether geometry can be applied to reality is an empirical question outside of geometry [Ayer] |
5197 | By changing definitions we could make 'a thing can't be in two places at once' a contradiction [Ayer] |
5204 | To say that a proposition is true a priori is to say that it is a tautology [Ayer] |
6524 | Positivists prefer sense-data to objects, because the vocabulary covers both illusions and perceptions [Ayer, by Robinson,H] |
5193 | Causal and representative theories of perception are wrong as they refer to unobservables [Ayer] |
5200 | The main claim of rationalism is that thought is an independent source of knowledge [Ayer] |
4729 | Empiricism lacked a decent account of the a priori, until Ayer said it was entirely analytic [O'Grady on Ayer] |
5180 | All propositions (especially 'metaphysics') must begin with the senses [Ayer] |
5169 | My empiricism logically distinguishes analytic and synthetic propositions, and metaphysical verbiage [Ayer] |
5185 | It is further sense-experience which informs us of the mistakes that arise out of sense-experience [Ayer] |
5199 | Empiricism, it is said, cannot account for our knowledge of necessary truths [Ayer] |
5190 | The induction problem is to prove generalisations about the future based on the past [Ayer] |
5191 | We can't use the uniformity of nature to prove induction, as that would be circular [Ayer] |
5177 | Other minds are 'metaphysical' objects, because I can never observe their experiences [Ayer] |
5178 | A conscious object is by definition one that behaves in a certain way, so behaviour proves consciousness [Ayer] |
5172 | If the self is meaningful, it must be constructed from sense-experiences [Ayer] |
5173 | Two experiences belong to one self if their contents belong with one body [Ayer] |
5176 | Empiricists can define personal identity as bodily identity, which consists of sense-contents [Ayer] |
5171 | The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances' [Ayer] |
5181 | A sentence is factually significant to someone if they know how to verify its proposition [Ayer] |
5184 | Factual propositions imply (in conjunction with a few other premises) possible experiences [Ayer] |
5186 | Tautologies and empirical hypotheses form the entire class of significant propositions [Ayer] |
5205 | Moral intuition is worthless if there is no criterion to decide between intuitions [Ayer] |
23725 | Ayer defends the emotivist version of expressivism [Ayer, by Smith,M] |
5206 | To say an act is wrong makes no further statement about it, but merely expresses disapproval [Ayer] |
6613 | The natural kinds are objects, processes and properties/relations [Ellis] |
6616 | Least action is not a causal law, but a 'global law', describing a global essence [Ellis] |
6615 | A species requires a genus, and its essence includes the essence of the genus [Ellis] |
6614 | A hierarchy of natural kinds is elaborate ontology, but needed to explain natural laws [Ellis] |
6612 | Without general principles, we couldn't predict the behaviour of dispositional properties [Ellis] |
5208 | A person with non-empirical attributes is unintelligible. [Ayer] |
5187 | When we ascribe an attribute to a thing, we covertly assert that it exists [Ayer] |
5207 | If theism is non-sensical, then so is atheism. [Ayer] |
5209 | The 'truths' expressed by theists are not literally significant [Ayer] |