115 ideas
| 21757 | Philosophy is the conceptual essence of the shape of history [Hegel] |
| 3722 | Metaphysics goes beyond the empirical, so doesn't need examples [Kant] |
| 3738 | The hallmark of rationality is setting itself an end [Kant] |
| 10073 | There cannot be a set theory which is complete [Smith,P] |
| 10616 | Second-order arithmetic can prove new sentences of first-order [Smith,P] |
| 10075 | A 'partial function' maps only some elements to another set [Smith,P] |
| 10074 | A 'total function' maps every element to one element in another set [Smith,P] |
| 10612 | An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P] |
| 10076 | The 'range' of a function is the set of elements in the output set created by the function [Smith,P] |
| 10605 | Two functions are the same if they have the same extension [Smith,P] |
| 10615 | The Comprehension Schema says there is a property only had by things satisfying a condition [Smith,P] |
| 10595 | A 'theorem' of a theory is a sentence derived from the axioms using the proof system [Smith,P] |
| 10602 | A 'natural deduction system' has no axioms but many rules [Smith,P] |
| 10613 | No nice theory can define truth for its own language [Smith,P] |
| 10078 | An 'injective' ('one-to-one') function creates a distinct output element from each original [Smith,P] |
| 10077 | A 'surjective' ('onto') function creates every element of the output set [Smith,P] |
| 10079 | A 'bijective' function has one-to-one correspondence in both directions [Smith,P] |
| 10070 | If everything that a theory proves is true, then it is 'sound' [Smith,P] |
| 10086 | Soundness is true axioms and a truth-preserving proof system [Smith,P] |
| 10596 | A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P] |
| 10598 | A theory is 'negation complete' if it proves all sentences or their negation [Smith,P] |
| 10597 | 'Complete' applies both to whole logics, and to theories within them [Smith,P] |
| 10069 | A theory is 'negation complete' if one of its sentences or its negation can always be proved [Smith,P] |
| 10609 | Two routes to Incompleteness: semantics of sound/expressible, or syntax of consistency/proof [Smith,P] |
| 10080 | 'Effective' means simple, unintuitive, independent, controlled, dumb, and terminating [Smith,P] |
| 10087 | A theory is 'decidable' if all of its sentences could be mechanically proved [Smith,P] |
| 10088 | Any consistent, axiomatized, negation-complete formal theory is decidable [Smith,P] |
| 10081 | A set is 'enumerable' is all of its elements can result from a natural number function [Smith,P] |
| 10083 | A set is 'effectively enumerable' if a computer could eventually list every member [Smith,P] |
| 10084 | A finite set of finitely specifiable objects is always effectively enumerable (e.g. primes) [Smith,P] |
| 10085 | The set of ordered pairs of natural numbers <i,j> is effectively enumerable [Smith,P] |
| 10601 | The thorems of a nice arithmetic can be enumerated, but not the truths (so they're diffferent) [Smith,P] |
| 10600 | Being 'expressible' depends on language; being 'capture/represented' depends on axioms and proof system [Smith,P] |
| 10599 | For primes we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))) [Smith,P] |
| 10610 | The reals contain the naturals, but the theory of reals doesn't contain the theory of naturals [Smith,P] |
| 10619 | The truths of arithmetic are just true equations and their universally quantified versions [Smith,P] |
| 10618 | All numbers are related to zero by the ancestral of the successor relation [Smith,P] |
| 10608 | The number of Fs is the 'successor' of the Gs if there is a single F that isn't G [Smith,P] |
| 10849 | Baby arithmetic covers addition and multiplication, but no general facts about numbers [Smith,P] |
| 10850 | Baby Arithmetic is complete, but not very expressive [Smith,P] |
| 10852 | Robinson Arithmetic (Q) is not negation complete [Smith,P] |
| 10851 | Robinson Arithmetic 'Q' has basic axioms, quantifiers and first-order logic [Smith,P] |
| 10068 | Natural numbers have zero, unique successors, unending, no circling back, and no strays [Smith,P] |
| 10603 | The logic of arithmetic must quantify over properties of numbers to handle induction [Smith,P] |
| 10848 | Multiplication only generates incompleteness if combined with addition and successor [Smith,P] |
| 10604 | Incompleteness results in arithmetic from combining addition and successor with multiplication [Smith,P] |
| 10617 | The 'ancestral' of a relation is a new relation which creates a long chain of the original relation [Smith,P] |
| 3726 | The categorical imperative is a practical synthetic a priori proposition [Kant] |
| 3739 | Free will is a kind of causality which works independently of other causes [Kant] |
| 3741 | We shall never be able to comprehend how freedom is possible [Kant] |
| 3740 | We cannot conceive of reason as being externally controlled [Kant] |
| 5296 | Kant made the political will into a pure self-determined "free" will [Kant, by Marx/Engels] |
| 24011 | Kant thought emotions are too random and passive to be part of morality [Kant, by Williams,B] |
| 5074 | Kant united religion and philosophy, by basing obedience to law on reason instead of faith [Taylor,R on Kant] |
| 8024 | The categorical imperative says nothing about what our activities and ends should be [MacIntyre on Kant] |
| 22390 | Kant thought human nature was pure hedonism, so virtue is only possible via the categorical imperative [Foot on Kant] |
| 9750 | We must only value what others find acceptable [Kant, by Korsgaard] |
| 20160 | Kant focuses exclusively on human values, and neglects cultural and personal values [Kekes on Kant] |
| 9749 | Our rational choices confer value, arising from the sense that we ourselves are important [Kant, by Korsgaard] |
| 7671 | Values are created by human choices, and are not some intrinsic quality, out there [Kant, by Berlin] |
| 3720 | We may claim noble motives, but we cannot penetrate our secret impulses [Kant] |
| 3717 | Reverence is awareness of a value which demolishes my self-love [Kant] |
| 3712 | A good will is not good because of what it achieves [Kant] |
| 3725 | The good of an action is in the mind of the doer, not the consequences [Kant] |
| 3733 | The 'golden rule' cannot be a universal law as it implies no duties [Kant] |
| 3736 | Virtue lets a rational being make universal law, and share in the kingdom of ends [Kant] |
| 3544 | Kant thinks virtue becomes passive, and hence morally unaccountable [Kant, by Annas] |
| 7674 | Generosity and pity are vices, because they falsely imply one person's superiority to another [Kant, by Berlin] |
| 21029 | Kantian respect is for humanity and reason (not from love or sympathy or solidarity) [Kant, by Sandel] |
| 7105 | If 'maxims' are deeper underlying intentions, Kant can be read as a virtue theorist [Kant, by Statman] |
| 7625 | We can ask how rational goodness is, but also why is rationality good [Putnam on Kant] |
| 3710 | The only purely good thing is a good will [Kant] |
| 3737 | The will is good if its universalised maxim is never in conflict with itself [Kant] |
| 3715 | Other causes can produce nice results, so morality must consist in the law, found only in rational beings [Kant] |
| 20715 | It is basic that moral actions must be done from duty [Kant] |
| 4024 | Kant follows Rousseau in defining freedom and morality in terms of each other [Taylor,C on Kant] |
| 3735 | Men are subject to laws which are both self-made and universal [Kant] |
| 3718 | Telling the truth from duty is quite different from doing so to avoid inconvenience [Kant] |
| 3723 | There are no imperatives for a holy will, as the will is in harmony with moral law [Kant] |
| 3724 | A categorical imperative sees an action as necessary purely for its own sake [Kant] |
| 3714 | Dutiful actions are judged not by purpose, but by the maxim followed [Kant] |
| 5295 | Kant was happy with 'good will', even if it had no result [Kant, by Marx/Engels] |
| 6695 | Kant has to attribute high moral worth to some deeply unattractive human lives [Kant, by Graham] |
| 8028 | Kantian duty seems to imply conformism with authority [MacIntyre on Kant] |
| 8026 | Almost any precept can be consistently universalized [MacIntyre on Kant] |
| 15673 | The intuition behind the categorical imperative is that one ought not to make an exception of oneself [Kant, by Finlayson] |
| 8068 | Universalising a maxim needs to first stipulate the right description for the action [Anscombe on Kant] |
| 8025 | The categorical imperative will not suggest maxims suitable for testing [MacIntyre on Kant] |
| 8027 | I can universalize a selfish maxim, if it is expressed in a way that only applies to me [MacIntyre on Kant] |
| 3728 | Suicide, false promises, neglected talent, and lack of charity all involve contradictions of principle [Kant, by PG] |
| 22008 | Always treat yourself and others as an end, and never simply as a means [Kant] |
| 22009 | Morality is the creation of the laws that enable a Kingdom of Ends [Kant] |
| 3719 | If lying were the universal law it would make promises impossible [Kant] |
| 3762 | Why couldn't all rational beings accept outrageously immoral rules of conduct? [Mill on Kant] |
| 4413 | The categorical imperative smells of cruelty [Nietzsche on Kant] |
| 3716 | Act according to a maxim you can will as a universal law [Kant] |
| 3727 | Act as if your maxim were to become a universal law of nature [Kant] |
| 22050 | The maxim of an action is chosen, and not externally imposed [Kant, by Bowie] |
| 6694 | Always treat humanity as an end and never as a means only [Kant] |
| 3731 | Rational beings necessarily conceive their own existence as an end in itself [Kant] |
| 4345 | For Kant, even a person who lacks all sympathy for others still has a motive for benevolence [Kant, by Hursthouse] |
| 4251 | If we are required to give moral thought the highest priority, this gives morality no content [Williams,B on Kant] |
| 16004 | If Kant lives by self-administered laws, this is as feeble as self-administered punishments [Kierkegaard on Kant] |
| 3711 | Only a good will makes us worthy of happiness [Kant] |
| 3713 | The function of reason is to produce a good will [Kant] |
| 3729 | Our inclinations are not innately desirable; in fact most rational beings would like to be rid of them [Kant] |
| 4344 | Actions where people spread happiness because they enjoy it have no genuine moral worth [Kant] |
| 3732 | Rational beings have a right to share in the end of an action, not just be part of the means [Kant] |
| 7670 | Kant is the father of the notion of exploitation as an evil [Kant, by Berlin] |
| 7591 | Kant completed Grotius's project of a non-religious basis for natural law [Scruton on Kant] |
| 7673 | Retributive punishment is better than being sent to hospital for your crimes [Kant, by Berlin] |
| 3730 | Non-rational beings only have a relative value, as means rather than as ends [Kant] |
| 3721 | We judge God to be good by a priori standards of moral perfection [Kant] |
| 8046 | We can only know we should obey God if we already have moral standards for judging God [Kant, by MacIntyre] |
| 20714 | God is not proved by reason, but is a postulate of moral thinking [Kant, by Davies,B] |