123 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] |
| 9123 | Someone standing in a doorway seems to be both in and not-in the room [Priest,G, by Sorensen] |
| 5331 | You can't infer that because you have a hidden birth-mark, everybody else does [Ayer] |
| 19463 | Induction assumes some uniformity in nature, or that in some respects the future is like the past [Ayer] |
| 4749 | We cannot analyse the concept of 'truth', because it is simply a mark that a sentence is asserted [Ayer] |
| 8720 | A logic is 'relevant' if premise and conclusion are connected, and 'paraconsistent' allows contradictions [Priest,G, by Friend] |
| 9672 | Free logic is one of the few first-order non-classical logics [Priest,G] |
| 9697 | X1 x X2 x X3... x Xn indicates the 'cartesian product' of those sets [Priest,G] |
| 9685 | <a,b&62; is a set whose members occur in the order shown [Priest,G] |
| 9675 | a ∈ X says a is an object in set X; a ∉ X says a is not in X [Priest,G] |
| 9674 | {x; A(x)} is a set of objects satisfying the condition A(x) [Priest,G] |
| 9673 | {a1, a2, ...an} indicates that a set comprising just those objects [Priest,G] |
| 9677 | Φ indicates the empty set, which has no members [Priest,G] |
| 9676 | {a} is the 'singleton' set of a (not the object a itself) [Priest,G] |
| 9679 | X⊂Y means set X is a 'proper subset' of set Y [Priest,G] |
| 9678 | X⊆Y means set X is a 'subset' of set Y [Priest,G] |
| 9681 | X = Y means the set X equals the set Y [Priest,G] |
| 9683 | X ∩ Y indicates the 'intersection' of sets X and Y, the objects which are in both sets [Priest,G] |
| 9682 | X∪Y indicates the 'union' of all the things in sets X and Y [Priest,G] |
| 9684 | Y - X is the 'relative complement' of X with respect to Y; the things in Y that are not in X [Priest,G] |
| 9694 | The 'relative complement' is things in the second set not in the first [Priest,G] |
| 9693 | The 'intersection' of two sets is a set of the things that are in both sets [Priest,G] |
| 9692 | The 'union' of two sets is a set containing all the things in either of the sets [Priest,G] |
| 9698 | The 'induction clause' says complex formulas retain the properties of their basic formulas [Priest,G] |
| 9688 | A 'singleton' is a set with only one member [Priest,G] |
| 9687 | A 'member' of a set is one of the objects in the set [Priest,G] |
| 9695 | An 'ordered pair' (or ordered n-tuple) is a set with its members in a particular order [Priest,G] |
| 9696 | A 'cartesian product' of sets is the set of all the n-tuples with one member in each of the sets [Priest,G] |
| 9686 | A 'set' is a collection of objects [Priest,G] |
| 9689 | The 'empty set' or 'null set' has no members [Priest,G] |
| 9690 | A set is a 'subset' of another set if all of its members are in that set [Priest,G] |
| 9691 | A 'proper subset' is smaller than the containing set [Priest,G] |
| 9680 | The empty set Φ is a subset of every set (including itself) [Priest,G] |
| 13373 | Typically, paradoxes are dealt with by dividing them into two groups, but the division is wrong [Priest,G] |
| 13368 | The 'least indefinable ordinal' is defined by that very phrase [Priest,G] |
| 13370 | 'x is a natural number definable in less than 19 words' leads to contradiction [Priest,G] |
| 13369 | By diagonalization we can define a real number that isn't in the definable set of reals [Priest,G] |
| 13366 | The least ordinal greater than the set of all ordinals is both one of them and not one of them [Priest,G] |
| 13367 | The next set up in the hierarchy of sets seems to be both a member and not a member of it [Priest,G] |
| 13371 | If you know that a sentence is not one of the known sentences, you know its truth [Priest,G] |
| 13372 | There are Liar Pairs, and Liar Chains, which fit the same pattern as the basic Liar [Priest,G] |
| 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] |
| 2611 | It is currently held that quantifying over something implies belief in its existence [Ayer] |
| 16520 | We see properties necessary for a kind (in the definition), but not for an individual [Ayer] |
| 5183 | Only tautologies can be certain; other propositions can only be probable [Ayer] |
| 19461 | Knowing I exist reveals nothing at all about my nature [Ayer] |
| 19459 | To say 'I am not thinking' must be false, but it might have been true, so it isn't self-contradictory [Ayer] |
| 19460 | 'I know I exist' has no counterevidence, so it may be meaningless [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] |
| 8824 | No one has defended translational phenomenalism since Ayer in 1940 [Ayer, by Kim] |
| 2614 | Modern phenomenalism holds that objects are logical constructions out of sense-data [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] |
| 2615 | The concept of sense-data allows us to discuss appearances without worrying about reality [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] |
| 5163 | Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable [Ayer] |
| 19464 | We only discard a hypothesis after one failure if it appears likely to keep on failing [Ayer] |
| 5190 | The induction problem is to prove generalisations about the future based on the past [Ayer] |
| 19462 | Induction passes from particular facts to other particulars, or to general laws, non-deductively [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] |
| 5662 | Maybe induction could never prove the existence of something unobservable [Ayer] |
| 5178 | A conscious object is by definition one that behaves in a certain way, so behaviour proves consciousness [Ayer] |
| 5167 | The argument from analogy fails, so the best account of other minds is behaviouristic [Ayer] |
| 2613 | The theory of other minds has no rival [Ayer] |
| 5328 | Originally I combined a mentalistic view of introspection with a behaviouristic view of other minds [Ayer] |
| 5330 | Physicalism undercuts the other mind problem, by equating experience with 'public' brain events [Ayer] |
| 5664 | Consciousness must involve a subject, and only bodies identify subjects [Ayer] |
| 5172 | If the self is meaningful, it must be constructed from sense-experiences [Ayer] |
| 5326 | Qualia must be united by a subject, because they lead to concepts and judgements [Ayer] |
| 5325 | Is something an 'experience' because it relates to other experiences, or because it relates to a subject? [Ayer] |
| 5324 | Bodily identity and memory work together to establish personal identity [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] |
| 5668 | People own conscious states because they are causally related to the identifying body [Ayer] |
| 5322 | Self-consciousness is not basic, because experiences are not instrinsically marked with ownership [Ayer] |
| 5661 | We identify experiences by their owners, so we can't define owners by their experiences [Ayer] |
| 5665 | Memory is the best proposal as what unites bundles of experiences [Ayer] |
| 5666 | Not all exerience can be remembered, as this would produce an infinite regress [Ayer] |
| 5327 | Temporal gaps in the consciousness of a spirit could not be bridged by memories [Ayer] |
| 5669 | Personal identity can't just be relations of experiences, because the body is needed to identify them [Ayer] |
| 5171 | The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances' [Ayer] |
| 5329 | Why shouldn't we say brain depends on mind? Better explanation! [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] |
| 5164 | A statement is meaningful if observation statements can be deduced from it [Ayer] |
| 5165 | Directly verifiable statements must entail at least one new observation statement [Ayer] |
| 5166 | The principle of verification is not an empirical hypothesis, but a definition [Ayer] |
| 5162 | Sentences only express propositions if they are meaningful; otherwise they are 'statements' [Ayer] |
| 2610 | Talk of propositions is just shorthand for talking about equivalent sentences [Ayer] |
| 6968 | Some people think there are ethical facts, but of a 'queer' sort [Ayer] |
| 6972 | A right attitude is just an attitude one is prepared to stand by [Ayer] |
| 6973 | Moral theories are all meta-ethical, and are neutral as regards actual conduct [Ayer] |
| 6974 | Moral judgements cannot be the logical consequence of a moral philosophy [Ayer] |
| 5205 | Moral intuition is worthless if there is no criterion to decide between intuitions [Ayer] |
| 6971 | I would describe intuitions of good as feelings of approval [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] |
| 6969 | Approval of historical or fictional murders gives us leave to imitate them [Ayer] |
| 6970 | Moral judgements are not expressions, but are elements in a behaviour pattern [Ayer] |
| 5168 | Moral approval and disapproval concerns classes of actions, rather than particular actions [Ayer] |
| 3031 | The greatest good is not the achievement of desire, but to desire what is proper [Menedemus, by Diog. Laertius] |
| 15251 | The attribution of necessity to causation is either primitive animism, or confusion with logical necessity [Ayer] |
| 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] |