104 ideas
| 22309 | An idea can only be like another idea [Berkeley] |
| 15413 | With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess] |
| 15415 | The temporal Barcan formulas fix what exists, which seems absurd [Burgess] |
| 15430 | Is classical logic a part of intuitionist logic, or vice versa? [Burgess] |
| 15431 | It is still unsettled whether standard intuitionist logic is complete [Burgess] |
| 15429 | Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess] |
| 15404 | Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess] |
| 15405 | Classical logic neglects the non-mathematical, such as temporality or modality [Burgess] |
| 15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
| 15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess] |
| 15403 | Philosophical logic is a branch of logic, and is now centred in computer science [Burgess] |
| 15407 | Formalising arguments favours lots of connectives; proving things favours having very few [Burgess] |
| 15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |
| 15409 | All occurrences of variables in atomic formulas are free [Burgess] |
| 15414 | The denotation of a definite description is flexible, rather than rigid [Burgess] |
| 15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
| 15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
| 15426 | We can build one expanding sequence, instead of a chain of deductions [Burgess] |
| 15408 | 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess] |
| 15418 | Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess] |
| 15412 | Models leave out meaning, and just focus on truth values [Burgess] |
| 15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
| 15416 | We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess] |
| 15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
| 18091 | Infinitesimals are ghosts of departed quantities [Berkeley] |
| 10185 | Set theory is the standard background for modern mathematics [Burgess] |
| 10184 | Structuralists take the name 'R' of the reals to be a variable ranging over structures, not a structure [Burgess] |
| 10189 | There is no one relation for the real number 2, as relations differ in different models [Burgess] |
| 10186 | If set theory is used to define 'structure', we can't define set theory structurally [Burgess] |
| 10187 | Abstract algebra concerns relations between models, not common features of all the models [Burgess] |
| 10188 | How can mathematical relations be either internal, or external, or intrinsic? [Burgess] |
| 6717 | Abstract ideas are impossible [Berkeley] |
| 3942 | I do not believe in the existence of anything, if I see no reason to believe it [Berkeley] |
| 3952 | I know that nothing inconsistent can exist [Berkeley] |
| 18876 | Berkeley does believe in trees, but is confused about what trees are [Berkeley, by Cameron] |
| 6715 | Universals do not have single meaning, but attach to many different particulars [Berkeley] |
| 6719 | No one will think of abstractions if they only have particular ideas [Berkeley] |
| 6714 | Universals do not have any intrinsic properties, but only relations to particulars [Berkeley] |
| 6729 | Material substance is just general existence which can have properties [Berkeley] |
| 3959 | There is no other substance, in a strict sense, than spirit [Berkeley] |
| 16636 | A die has no distinct subject, but is merely a name for its modes or accidents [Berkeley] |
| 15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
| 15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
| 15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
| 3946 | A thing is shown to be impossible if a contradiction is demonstrated within its definition [Berkeley] |
| 15422 | Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess] |
| 15423 | It is doubtful whether the negation of a conditional has any clear meaning [Burgess] |
| 3958 | Since our ideas vary when the real things are said to be unchanged, they cannot be true copies [Berkeley] |
| 3943 | If existence is perceived directly, by which sense; if indirectly, how is it inferred from direct perception? [Berkeley] |
| 3931 | Sensible objects are just sets of sensible qualities [Berkeley] |
| 6722 | Perception is existence for my table, but also possible perception, by me or a spirit [Berkeley] |
| 5192 | Berkeley did not deny material things; he merely said they must be defined through sensations [Berkeley, by Ayer] |
| 5174 | Berkeley needed a phenomenalist account of the self, as well as of material things [Ayer on Berkeley] |
| 6724 | The only substance is spirit, or that which perceives [Berkeley] |
| 6723 | The 'esse' of objects is 'percipi', and they can only exist in minds [Berkeley] |
| 6732 | When I shut my eyes, the things I saw may still exist, but in another mind [Berkeley] |
| 1103 | 'To be is to be perceived' is a simple confusion of experience with its objects [Russell on Berkeley] |
| 6403 | For Berkelely, reality is ideas and a community of minds, including God's [Berkeley, by Grayling] |
| 3936 | Time is measured by the succession of ideas in our minds [Berkeley] |
| 3930 | There is no such thing as 'material substance' [Berkeley] |
| 3939 | I conceive a tree in my mind, but I cannot prove that its existence can be conceived outside a mind [Berkeley] |
| 3945 | There is nothing in nature which needs the concept of matter to explain it [Berkeley] |
| 3947 | Perceptions are ideas, and ideas exist in the mind, so objects only exist in the mind [Berkeley] |
| 3933 | Primary qualities (such as shape, solidity, mass) are held to really exist, unlike secondary qualities [Berkeley] |
| 6726 | No one can, by abstraction, conceive extension and motion of bodies without sensible qualities [Berkeley] |
| 6728 | Motion is in the mind, since swifter ideas produce an appearance of slower motion [Berkeley] |
| 6727 | Figure and extension seem just as dependent on the observer as heat and cold [Berkeley] |
| 3934 | A mite would see its own foot as large, though we would see it as tiny [Berkeley] |
| 3935 | The apparent size of an object varies with its distance away, so that can't be a property of the object [Berkeley] |
| 3937 | 'Solidity' is either not a sensible quality at all, or it is clearly relative to our senses [Berkeley] |
| 3940 | Distance is not directly perceived by sight [Berkeley] |
| 6495 | Berkeley's idealism resulted from fear of scepticism in representative realism [Robinson,H on Berkeley] |
| 3957 | Immediate objects of perception, which some treat as appearances, I treat as the real things themselves [Berkeley] |
| 6720 | Knowledge is of ideas from senses, or ideas of the mind, or operations on sensations [Berkeley] |
| 3953 | Real things and imaginary or dreamed things differ because the latter are much fainter [Berkeley] |
| 3938 | Geometry is originally perceived by senses, and so is not purely intellectual [Berkeley] |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| 3944 | It is possible that we could perceive everything as we do now, but nothing actually existed. [Berkeley] |
| 3932 | A hot hand and a cold hand will have different experiences in the same tepid water [Berkeley] |
| 23636 | Berkeley's idealism gives no grounds for believing in other minds [Reid on Berkeley] |
| 6736 | I know other minds by ideas which are referred by me to other agents, as their effects [Berkeley] |
| 3948 | Experience tells me that other minds exist independently from my own [Berkeley] |
| 6713 | If animals have ideas, and are not machines, they must have some reason [Berkeley] |
| 6491 | Berkeley replaced intentionality with an anti-abstractionist imagist theory of thought [Berkeley, by Robinson,H] |
| 6711 | The mind creates abstract ideas by considering qualities separated from their objects [Berkeley] |
| 10581 | I can only combine particulars in imagination; I can't create 'abstract' ideas [Berkeley] |
| 6721 | Ideas are perceived by the mind, soul or self [Berkeley] |
| 3941 | How can that which is unthinking be a cause of thought? [Berkeley] |
| 5374 | Berkeley probably used 'idea' to mean both the act of apprehension and the thing apprehended [Russell on Berkeley] |
| 6716 | Language is presumably for communication, and names stand for ideas [Berkeley] |
| 6718 | I can't really go wrong if I stick to wordless thought [Berkeley] |
| 3954 | Immorality is not in the action, but in the deviation of the will from moral law [Berkeley] |
| 6731 | No one can explain how matter affects mind, so matter is redundant in philosophy [Berkeley] |
| 6730 | We discover natural behaviour by observing settled laws of nature, not necessary connections [Berkeley] |
| 15861 | The laws of nature are mental regularities which we learn by experience [Berkeley] |
| 6734 | If properties and qualities arise from an inward essence, we will remain ignorant of nature [Berkeley] |
| 6735 | All motion is relative, so a single body cannot move [Berkeley] |
| 6733 | I cannot imagine time apart from the flow of ideas in my mind [Berkeley] |
| 3950 | There must be a God, because all sensible things must be perceived by him [Berkeley] |
| 3951 | There must be a God, because I and my ideas are not independent [Berkeley] |
| 3949 | It has been proved that creation is the workmanship of God, from its beauty and usefulness [Berkeley] |
| 6737 | Particular evils are really good when linked to the whole system of beings [Berkeley] |
| 3956 | People are responsible because they have limited power, though this ultimately derives from God [Berkeley] |
| 3955 | If sin is not just physical, we don't consider God the origin of sin because he causes physical events [Berkeley] |