63 ideas
| 17663 | If you know what it is, investigation is pointless. If you don't, investigation is impossible [Armstrong] |
| 4643 | The Principle of Sufficient Reason does not presuppose that all explanations will be causal explanations [Baggini /Fosl] |
| 4633 | You cannot rationally deny the principle of non-contradiction, because all reasoning requires it [Baggini /Fosl] |
| 4635 | Dialectic aims at unified truth, unlike analysis, which divides into parts [Baggini /Fosl] |
| 4632 | 'Natural' systems of deduction are based on normal rational practice, rather than on axioms [Baggini /Fosl] |
| 4631 | In ideal circumstances, an axiom should be such that no rational agent could possibly object to its use [Baggini /Fosl] |
| 10482 | The logic of ZF is classical first-order predicate logic with identity [Boolos] |
| 10492 | A few axioms of set theory 'force themselves on us', but most of them don't [Boolos] |
| 10485 | Naïve sets are inconsistent: there is no set for things that do not belong to themselves [Boolos] |
| 10484 | The iterative conception says sets are formed at stages; some are 'earlier', and must be formed first [Boolos] |
| 4638 | The principle of bivalence distorts reality, as when claiming that a person is or is not 'thin' [Baggini /Fosl] |
| 10491 | Infinite natural numbers is as obvious as infinite sentences in English [Boolos] |
| 10483 | Mathematics and science do not require very high orders of infinity [Boolos] |
| 10490 | Mathematics isn't surprising, given that we experience many objects as abstract [Boolos] |
| 17688 | Negative facts are supervenient on positive facts, suggesting they are positive facts [Armstrong] |
| 17691 | Nothing is genuinely related to itself [Armstrong] |
| 17679 | All instances of some property are strictly identical [Armstrong] |
| 12677 | Armstrong holds that all basic properties are categorical [Armstrong, by Ellis] |
| 17666 | Actualism means that ontology cannot contain what is merely physically possible [Armstrong] |
| 17667 | Dispositions exist, but their truth-makers are actual or categorical properties [Armstrong] |
| 17687 | If everything is powers there is a vicious regress, as powers are defined by more powers [Armstrong] |
| 17678 | Universals are just the repeatable features of a world [Armstrong] |
| 10488 | It is lunacy to think we only see ink-marks, and not word-types [Boolos] |
| 17669 | Realist regularity theories of laws need universals, to pick out the same phenomena [Armstrong] |
| 17677 | Past, present and future must be equally real if universals are instantiated [Armstrong] |
| 17686 | Universals are abstractions from states of affairs [Armstrong] |
| 15442 | Universals are abstractions from their particular instances [Armstrong, by Lewis] |
| 10487 | I am a fan of abstract objects, and confident of their existence [Boolos] |
| 10489 | We deal with abstract objects all the time: software, poems, mistakes, triangles.. [Boolos] |
| 17668 | It is likely that particulars can be individuated by unique conjunctions of properties [Armstrong] |
| 4640 | If identity is based on 'true of X' instead of 'property of X' we get the Masked Man fallacy ('I know X but not Y') [Baggini /Fosl, by PG] |
| 4647 | 'I have the same car as you' is fine; 'I have the same fiancée as you' is not so good [Baggini /Fosl] |
| 17680 | The identity of a thing with itself can be ruled out as a pseudo-property [Armstrong] |
| 4639 | Leibniz's Law is about the properties of objects; the Identity of Indiscernibles is about perception of objects [Baggini /Fosl] |
| 4646 | Is 'events have causes' analytic a priori, synthetic a posteriori, or synthetic a priori? [Baggini /Fosl] |
| 17693 | The necessary/contingent distinction may need to recognise possibilities as real [Armstrong] |
| 4645 | 'A priori' does not concern how you learn a proposition, but how you show whether it is true or false [Baggini /Fosl] |
| 4582 | Basic beliefs are self-evident, or sensual, or intuitive, or revealed, or guaranteed [Baggini /Fosl] |
| 4644 | A proposition such as 'some swans are purple' cannot be falsified, only verified [Baggini /Fosl] |
| 4584 | The problem of induction is how to justify our belief in the uniformity of nature [Baggini /Fosl] |
| 17685 | Induction aims at 'all Fs', but abduction aims at hidden or theoretical entities [Armstrong] |
| 4583 | How can an argument be good induction, but poor deduction? [Baggini /Fosl] |
| 17683 | Science suggests that the predicate 'grue' is not a genuine single universal [Armstrong] |
| 17675 | Unlike 'green', the 'grue' predicate involves a time and a change [Armstrong] |
| 17674 | The raven paradox has three disjuncts, confirmed by confirming any one of them [Armstrong] |
| 17672 | A good reason for something (the smoke) is not an explanation of it (the fire) [Armstrong] |
| 17684 | To explain observations by a regular law is to explain the observations by the observations [Armstrong] |
| 4634 | Abduction aims at simplicity, testability, coherence and comprehensiveness [Baggini /Fosl] |
| 4637 | To see if an explanation is the best, it is necessary to investigate the alternative explanations [Baggini /Fosl] |
| 17676 | Best explanations explain the most by means of the least [Armstrong] |
| 4629 | Consistency is the cornerstone of rationality [Baggini /Fosl] |
| 17664 | Each subject has an appropriate level of abstraction [Armstrong] |
| 17692 | We can't deduce the phenomena from the One [Armstrong] |
| 17689 | Absences might be effects, but surely not causes? [Armstrong] |
| 17662 | Science depends on laws of nature to study unobserved times and spaces [Armstrong] |
| 17682 | A universe couldn't consist of mere laws [Armstrong] |
| 17690 | Oaken conditional laws, Iron universal laws, and Steel necessary laws [Armstrong, by PG] |
| 17670 | Newton's First Law refers to bodies not acted upon by a force, but there may be no such body [Armstrong] |
| 8582 | Regularities are lawful if a second-order universal unites two first-order universals [Armstrong, by Lewis] |
| 17671 | A naive regularity view says if it never occurs then it is impossible [Armstrong] |
| 17681 | The laws of nature link properties with properties [Armstrong] |
| 16246 | Rather than take necessitation between universals as primitive, just make laws primitive [Maudlin on Armstrong] |
| 9480 | Armstrong has an unclear notion of contingent necessitation, which can't necessitate anything [Bird on Armstrong] |