133 ideas
| 19807 | Both nature and reason require that everything has a cause [Rousseau] |
| 9955 | Contextual definitions replace a complete sentence containing the expression [George/Velleman] |
| 10031 | Impredicative definitions quantify over the thing being defined [George/Velleman] |
| 10098 | The 'power set' of A is all the subsets of A [George/Velleman] |
| 10099 | The 'ordered pair' <a, b>, for two sets a and b, is the set {{a, b},{a}} [George/Velleman] |
| 10101 |
Cartesian Product A x B: the set of all ordered pairs |
| 10103 | Grouping by property is common in mathematics, usually using equivalence [George/Velleman] |
| 10104 | 'Equivalence' is a reflexive, symmetric and transitive relation; 'same first letter' partitions English words [George/Velleman] |
| 10096 | Even the elements of sets in ZFC are sets, resting on the pure empty set [George/Velleman] |
| 10097 | Axiom of Extensionality: for all sets x and y, if x and y have the same elements then x = y [George/Velleman] |
| 10100 | Axiom of Pairing: for all sets x and y, there is a set z containing just x and y [George/Velleman] |
| 17900 | The Axiom of Reducibility made impredicative definitions possible [George/Velleman] |
| 10109 | ZFC can prove that there is no set corresponding to the concept 'set' [George/Velleman] |
| 10108 | As a reduction of arithmetic, set theory is not fully general, and so not logical [George/Velleman] |
| 10111 | Asserting Excluded Middle is a hallmark of realism about the natural world [George/Velleman] |
| 10129 | A 'model' is a meaning-assignment which makes all the axioms true [George/Velleman] |
| 10105 | Differences between isomorphic structures seem unimportant [George/Velleman] |
| 10119 | Consistency is a purely syntactic property, unlike the semantic property of soundness [George/Velleman] |
| 10126 | A 'consistent' theory cannot contain both a sentence and its negation [George/Velleman] |
| 10120 | Soundness is a semantic property, unlike the purely syntactic property of consistency [George/Velleman] |
| 10127 | A 'complete' theory contains either any sentence or its negation [George/Velleman] |
| 10106 | Rational numbers give answers to division problems with integers [George/Velleman] |
| 10102 | The integers are answers to subtraction problems involving natural numbers [George/Velleman] |
| 10107 | Real numbers provide answers to square root problems [George/Velleman] |
| 9946 | Logicists say mathematics is applicable because it is totally general [George/Velleman] |
| 10125 | The classical mathematician believes the real numbers form an actual set [George/Velleman] |
| 17899 | Second-order induction is stronger as it covers all concepts, not just first-order definable ones [George/Velleman] |
| 10128 | The Incompleteness proofs use arithmetic to talk about formal arithmetic [George/Velleman] |
| 17902 | A successor is the union of a set with its singleton [George/Velleman] |
| 10133 | Frege's Theorem shows the Peano Postulates can be derived from Hume's Principle [George/Velleman] |
| 10130 | Set theory can prove the Peano Postulates [George/Velleman] |
| 10089 | Talk of 'abstract entities' is more a label for the problem than a solution to it [George/Velleman] |
| 10131 | If mathematics is not about particulars, observing particulars must be irrelevant [George/Velleman] |
| 10092 | In the unramified theory of types, the types are objects, then sets of objects, sets of sets etc. [George/Velleman] |
| 10094 | The theory of types seems to rule out harmless sets as well as paradoxical ones. [George/Velleman] |
| 10095 | Type theory has only finitely many items at each level, which is a problem for mathematics [George/Velleman] |
| 17901 | Type theory prohibits (oddly) a set containing an individual and a set of individuals [George/Velleman] |
| 10114 | Bounded quantification is originally finitary, as conjunctions and disjunctions [George/Velleman] |
| 10134 | Much infinite mathematics can still be justified finitely [George/Velleman] |
| 10123 | The intuitionists are the idealists of mathematics [George/Velleman] |
| 10124 | Gödel's First Theorem suggests there are truths which are independent of proof [George/Velleman] |
| 14221 | Serious essentialism says everything has essences, they're not things, and they ground necessities [Shalkowski] |
| 14222 | Essences are what it is to be that (kind of) thing - in fact, they are the thing's identity [Shalkowski] |
| 14226 | We distinguish objects by their attributes, not by their essences [Shalkowski] |
| 14225 | Critics say that essences are too mysterious to be known [Shalkowski] |
| 14223 | De dicto necessity has linguistic entities as their source, so it is a type of de re necessity [Shalkowski] |
| 10110 | Corresponding to every concept there is a class (some of them sets) [George/Velleman] |
| 14224 | Equilateral and equiangular aren't the same, as we have to prove their connection [Shalkowski] |
| 7235 | Without freedom of will actions lack moral significance [Rousseau] |
| 19791 | Natural mankind is too fragmented for states of peace, or of war and enmity [Rousseau] |
| 20501 | Rousseau assumes that laws need a people united by custom and tradition [Rousseau, by Wolff,J] |
| 7237 | The act of becoming 'a people' is the real foundation of society [Rousseau] |
| 19792 | To overcome obstacles, people must unite their forces into a single unified power [Rousseau] |
| 19812 | Human nature changes among a people, into a moral and partial existence [Rousseau] |
| 19814 | A state must be big enough to preserve itself, but small enough to be governable [Rousseau] |
| 19815 | Too much land is a struggle, producing defensive war; too little makes dependence, and offensive war [Rousseau] |
| 19822 | If the state enlarges, the creators of the general will become less individually powerful [Rousseau] |
| 19823 | If the population is larger, the government needs to be more powerful [Rousseau] |
| 7232 | Man is born free, and he is everywhere in chains [Rousseau] |
| 7234 | No man has any natural authority over his fellows [Rousseau] |
| 19816 | A state's purpose is liberty and equality - liberty for strength, and equality for liberty [Rousseau] |
| 7247 | The greatest social good comes down to freedom and equality [Rousseau] |
| 19838 | The measure of a successful state is increase in its population [Rousseau] |
| 19848 | The sovereignty does not appoint the leaders [Rousseau] |
| 20567 | Rousseau insists that popular sovereignty needs a means of expressing consent [Rousseau, by Oksala] |
| 19801 | Sovereignty is the exercise of the general will, which can never be delegated [Rousseau] |
| 19805 | Just as people control their limbs, the general-will state has total control of its members [Rousseau] |
| 19818 | Political laws are fundamental, as they firmly organise the state - but they could still be changed [Rousseau] |
| 19790 | Force can only dominate if it is seen as a right, and obedience as a duty [Rousseau] |
| 7233 | The social order is a sacred right, but based on covenants, not nature [Rousseau] |
| 19842 | The government is instituted by a law, not by a contract [Rousseau] |
| 7239 | The social pact is the total subjection of individuals to the general will [Rousseau] |
| 19793 | We need a protective association which unites forces, but retains individual freedom [Rousseau] |
| 7240 | To foreign powers a state is seen as a simple individual [Rousseau] |
| 19795 | The act of association commits citizens to the state, and the state to its citizens [Rousseau] |
| 19797 | Citizens must ultimately for forced to accept the general will (so freedom is compulsory!) [Rousseau] |
| 19796 | Individual citizens still retain a private will, which may be contrary to the general will [Rousseau] |
| 7244 | The general will is common interest; the will of all is the sum of individual desires [Rousseau] |
| 19802 | The general will is always right, but the will of all can err, because it includes private interests [Rousseau] |
| 19803 | If the state contains associations there are fewer opinions, undermining the general will [Rousseau] |
| 19804 | If a large knowledgeable population votes in isolation, their many choices will have good results [Rousseau] |
| 19808 | The general will changes its nature when it focuses on particulars [Rousseau] |
| 7246 | The general will is always good, but sometimes misunderstood [Rousseau] |
| 7250 | Laws are authentic acts of the general will [Rousseau] |
| 19844 | Assemblies must always confirm the form of government, and the current administration [Rousseau] |
| 19846 | The more unanimous the assembly, the stronger the general will becomes [Rousseau] |
| 19817 | Citizens should be independent of each other, and very dependent on the state [Rousseau] |
| 19840 | A citizen is a subject who is also sovereign [Rousseau] |
| 19839 | The flourishing of arts and letters is too much admired [Rousseau] |
| 19798 | Ancient monarchs were kings of peoples; modern monarchs more cleverly rule a land [Rousseau] |
| 19831 | The highest officers under a monarchy are normally useless; the public could choose much better [Rousseau] |
| 19833 | Hereditary monarchy is easier, but can lead to dreadful monarchs [Rousseau] |
| 19834 | Attempts to train future kings don't usually work, and the best have been unprepared [Rousseau] |
| 19829 | Natural aristocracy is primitive, and hereditary is dreadful, but elective aristocracy is best [Rousseau] |
| 7249 | Natural aristocracy is primitive, hereditary is bad, and elective aristocracy is the best [Rousseau] |
| 19830 | Large states need a nobility to fill the gap between a single prince and the people [Rousseau] |
| 19827 | Law makers and law implementers should be separate [Rousseau] |
| 19820 | The state has a legislature and an executive, just like the will and physical power in a person [Rousseau] |
| 19821 | I call the executive power the 'government', which is the 'prince' - a single person, or a group [Rousseau] |
| 19824 | Large populations needs stronger control, which means power should be concentrated [Rousseau] |
| 19826 | Democracy for small states, aristocracy for intermediate, monarchy for large [Rousseau] |
| 19837 | If inhabitants are widely dispersed, organising a revolt is much more difficult [Rousseau] |
| 19843 | The state is not bound to leave civil authority to its leaders [Rousseau] |
| 19825 | If the sovereign entrusts government to at least half the citizens, that is 'democracy' [Rousseau] |
| 19832 | Democratic elections are dangerous intervals in government [Rousseau] |
| 7243 | Silence of the people implies their consent [Rousseau] |
| 7251 | The English are actually slaves in between elections [Rousseau] |
| 7238 | Minorities only accept majority-voting because of a prior unanimous agreement [Rousseau] |
| 19828 | Democracy leads to internal strife, as people struggle to maintain or change ways of ruling [Rousseau] |
| 19835 | When ministers change the state changes, because they always reverse policies [Rousseau] |
| 19849 | In early theocracies the god was the king, and there were as many gods as nations [Rousseau] |
| 19841 | Sometimes full liberty is only possible at the expense of some complete enslavement [Rousseau] |
| 19847 | We can never assume that the son of a slave is a slave [Rousseau] |
| 7242 | Appetite alone is slavery, and self-prescribed laws are freedom [Rousseau] |
| 19800 | The social compact imposes conventional equality of rights on people who may start unequally [Rousseau] |
| 7248 | No citizen should be rich enough to buy another, and none so poor as forced to sell himself [Rousseau] |
| 19794 | If we all give up all of our rights together to the community, we will always support one another [Rousseau] |
| 7241 | In society man loses natural liberty, but gains a right to civil liberty and property [Rousseau] |
| 19806 | We alienate to society only what society needs - but society judges that, not us [Rousseau] |
| 19799 | Private property must always be subordinate to ownership by the whole community [Rousseau] |
| 19819 | The state ensures liberty, so civil law separates citizens, and binds them to the state [Rousseau] |
| 7245 | Natural justice, without sanctions, benefits the wicked, who exploit it [Rousseau] |
| 19809 | We accept the death penalty to prevent assassinations, so we must submit to it if necessary [Rousseau] |
| 19810 | A trial proves that a criminal has broken the social treaty, and is no longer a member of the state [Rousseau] |
| 19811 | Only people who are actually dangerous should be executed, even as an example [Rousseau] |
| 7236 | War gives no right to inflict more destruction than is necessary for victory [Rousseau] |
| 23607 | Wars are between States, not people, and the individuals are enemies by accident [Rousseau] |
| 19850 | By separating theological and political systems, Jesus caused divisions in the state [Rousseau] |
| 19852 | Civil religion needs one supreme god, an afterlife, justice, and the sanctity of the social contract [Rousseau] |
| 19853 | All religions should be tolerated, if they tolerate each other, and support citizenship [Rousseau] |
| 19851 | Every society has a religion as its base [Rousseau] |
| 19836 | The amount of taxation doesn't matter, if it quickly circulates back to the citizens [Rousseau] |
| 7252 | A tyrant exploits Christians because they don't value this life, and are made to be slaves [Rousseau] |