78 ideas
3811 | Entailment and validity are relations, but inference is a human activity [Searle] |
3822 | Theory involves accepting conclusions, and so is a special case of practical reason [Searle] |
3812 | Rationality is the way we coordinate our intentionality [Searle] |
3806 | Rationality is built into the intentionality of the mind, and its means of expression [Searle] |
20768 | Like spiderswebs, dialectical arguments are clever but useless [Ariston, by Diog. Laertius] |
8721 | An 'impredicative' definition seems circular, because it uses the term being defined [Friend] |
8680 | Classical definitions attempt to refer, but intuitionist/constructivist definitions actually create objects [Friend] |
3678 | Reductio ad absurdum proves an idea by showing that its denial produces contradiction [Friend] |
8705 | Anti-realists see truth as our servant, and epistemically contrained [Friend] |
8713 | In classical/realist logic the connectives are defined by truth-tables [Friend] |
8708 | Double negation elimination is not valid in intuitionist logic [Friend] |
8694 | Free logic was developed for fictional or non-existent objects [Friend] |
8665 | A 'proper subset' of A contains only members of A, but not all of them [Friend] |
8672 | A 'powerset' is all the subsets of a set [Friend] |
8677 | Set theory makes a minimum ontological claim, that the empty set exists [Friend] |
8666 | Infinite sets correspond one-to-one with a subset [Friend] |
8682 | Major set theories differ in their axioms, and also over the additional axioms of choice and infinity [Friend] |
3809 | If complex logic requires rules, then so does basic logic [Searle] |
8709 | The law of excluded middle is syntactic; it just says A or not-A, not whether they are true or false [Friend] |
8711 | Intuitionists read the universal quantifier as "we have a procedure for checking every..." [Friend] |
3810 | In real reasoning semantics gives validity, not syntax [Searle] |
8675 | Paradoxes can be solved by talking more loosely of 'classes' instead of 'sets' [Friend] |
8674 | The Burali-Forti paradox asks whether the set of all ordinals is itself an ordinal [Friend] |
8667 | The 'integers' are the positive and negative natural numbers, plus zero [Friend] |
8668 | The 'rational' numbers are those representable as fractions [Friend] |
8670 | A number is 'irrational' if it cannot be represented as a fraction [Friend] |
8661 | The natural numbers are primitive, and the ordinals are up one level of abstraction [Friend] |
8664 | Cardinal numbers answer 'how many?', with the order being irrelevant [Friend] |
8671 | The 'real' numbers (rationals and irrationals combined) is the Continuum, which has no gaps [Friend] |
8663 | Raising omega to successive powers of omega reveal an infinity of infinities [Friend] |
8662 | The first limit ordinal is omega (greater, but without predecessor), and the second is twice-omega [Friend] |
8669 | Between any two rational numbers there is an infinite number of rational numbers [Friend] |
8676 | Is mathematics based on sets, types, categories, models or topology? [Friend] |
8678 | Most mathematical theories can be translated into the language of set theory [Friend] |
8701 | The number 8 in isolation from the other numbers is of no interest [Friend] |
8702 | In structuralism the number 8 is not quite the same in different structures, only equivalent [Friend] |
8699 | Are structures 'ante rem' (before reality), or are they 'in re' (grounded in physics)? [Friend] |
8696 | Structuralist says maths concerns concepts about base objects, not base objects themselves [Friend] |
8695 | Structuralism focuses on relations, predicates and functions, with objects being inessential [Friend] |
8700 | 'In re' structuralism says that the process of abstraction is pattern-spotting [Friend] |
8681 | The big problem for platonists is epistemic: how do we perceive, intuit, know or detect mathematical facts? [Friend] |
8712 | Mathematics should be treated as true whenever it is indispensable to our best physical theory [Friend] |
8716 | Formalism is unconstrained, so cannot indicate importance, or directions for research [Friend] |
8706 | Constructivism rejects too much mathematics [Friend] |
8707 | Intuitionists typically retain bivalence but reject the law of excluded middle [Friend] |
3841 | Users of 'supervenience' blur its causal and constitutive meanings [Searle] |
8704 | Structuralists call a mathematical 'object' simply a 'place in a structure' [Friend] |
3816 | Our beliefs are about things, not propositions (which are the content of the belief) [Searle] |
3833 | A belief is a commitment to truth [Searle] |
3837 | We can't understand something as a lie if beliefs aren't commitment to truth [Searle] |
3828 | Thinking must involve a self, not just an "it" [Searle] |
3831 | Reasons can either be facts in the world, or intentional states [Searle] |
3830 | In the past people had a reason not to smoke, but didn't realise it [Searle] |
3832 | Causes (usually events) are not the same as reasons (which are never events) [Searle] |
3823 | Being held responsible for past actions makes no sense without personal identity [Searle] |
3821 | Giving reasons for action requires reference to a self [Searle] |
3824 | A 'self' must be capable of conscious reasonings about action [Searle] |
3834 | An intentional, acting, rational being must have a self [Searle] |
3825 | Action requires a self, even though perception doesn't [Searle] |
3826 | A self must at least be capable of consciousness [Searle] |
3829 | Selfs are conscious, enduring, reasonable, active, free, and responsible [Searle] |
3827 | The self is neither an experience nor a thing experienced [Searle] |
3820 | The bundle must also have agency in order to act, and a self to act rationally [Searle] |
3808 | Rational decision making presupposes free will [Searle] |
3817 | Free will is most obvious when we choose between several reasons for an action [Searle] |
3818 | We freely decide whether to make a reason for action effective [Searle] |
8685 | Studying biology presumes the laws of chemistry, and it could never contradict them [Friend] |
8688 | Concepts can be presented extensionally (as objects) or intensionally (as a characterization) [Friend] |
3814 | Preferences can result from deliberation, not just precede it [Searle] |
3840 | We don't accept practical reasoning if the conclusion is unpalatable [Searle] |
3815 | The essence of humanity is desire-independent reasons for action [Searle] |
3839 | Only an internal reason can actually motivate the agent to act [Searle] |
3835 | If it is true, you ought to believe it [Searle] |
3836 | If this is a man, you ought to accept similar things as men [Searle] |
3838 | Promises hold because I give myself a reason, not because it is an institution [Searle] |
3049 | The chief good is indifference to what lies midway between virtue and vice [Ariston, by Diog. Laertius] |
3549 | Ariston says rules are useless for the virtuous and the non-virtuous [Ariston, by Annas] |
3813 | 'Ought' implies that there is a reason to do something [Searle] |