100 ideas
| 7113 | Phenomenology assumes that all consciousness is of something [Sartre] |
| 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] |
| 10101 |
Cartesian Product A x B: the set of all ordered pairs |
| 10099 | The 'ordered pair' <a, b>, for two sets a and b, is the set {{a, b},{a}} [George/Velleman] |
| 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] |
| 22227 | For Sartre there is only being for-itself, or being in-itself (which is beyond experience) [Sartre, by Daigle] |
| 7114 | The consciousness that says 'I think' is not the consciousness that thinks [Sartre] |
| 7112 | The Cogito depends on a second-order experience, of being conscious of consciousness [Sartre] |
| 7119 | Is the Cogito reporting an immediate experience of doubting, or the whole enterprise of doubting? [Sartre] |
| 20743 | Appearances do not hide the essence; appearances are the essence [Sartre] |
| 7125 | A consciousness can conceive of no other consciousness than itself [Sartre] |
| 7122 | We can never, even in principle, grasp other minds, because the Ego is self-conceiving [Sartre] |
| 7108 | The eternal truth of 2+2=4 is what gives unity to the mind which regularly thinks it [Sartre] |
| 24016 | Consciousness always transcends itself [Sartre] |
| 6151 | Sartre says consciousness is just directedness towards external objects [Sartre, by Rowlands] |
| 7111 | Consciousness exists as consciousness of itself [Sartre] |
| 22226 | Since we are a consciousness, Sartre entirely rejected the unconscious mind [Sartre, by Daigle] |
| 7107 | Intentionality defines, transcends and unites consciousness [Sartre] |
| 3847 | Man is nothing else but the sum of his actions [Sartre] |
| 7109 | If you think of '2+2=4' as the content of thought, the self must be united transcendentally [Sartre] |
| 7106 | The Ego is not formally or materially part of consciousness, but is outside in the world [Sartre] |
| 16236 | Maybe our persistence conditions concern bodies, rather than persons [Olson, by Hawley] |
| 6669 | For 'animalism', I exist before I became a person, and can continue after it, so I am not a person [Olson, by Lowe] |
| 7117 | How could two I's, the reflective and the reflected, communicate with each other? [Sartre] |
| 7123 | Knowing yourself requires an exterior viewpoint, which is necessarily false [Sartre] |
| 22225 | My ego is more intimate to me, but not more certain than other egos [Sartre] |
| 7116 | When we are unreflective (as when chasing a tram) there is no 'I' [Sartre] |
| 7124 | The Ego never appears except when we are not looking for it [Sartre] |
| 7120 | It is theoretically possible that the Ego consists entirely of false memories [Sartre] |
| 7110 | If the 'I' is transcendental, it unnecessarily splits consciousness in two [Sartre] |
| 7115 | Maybe it is the act of reflection that brings 'me' into existence [Sartre] |
| 7121 | The Ego only appears to reflection, so it is cut off from the World [Sartre] |
| 3846 | Man IS freedom [Sartre] |
| 24013 | An emotion and its object form a unity, so emotion is a mode of apprehension [Sartre] |
| 24017 | Emotion is one of our modes of understanding our Being-in-the-World [Sartre] |
| 24014 | Emotions are a sort of bodily incantation which brings a magic to the world [Sartre] |
| 24015 | Emotions makes us believe in and live in a new world [Sartre] |
| 6164 | Sartre rejects mental content, and the idea that the mind has hidden inner features [Sartre, by Rowlands] |
| 10110 | Corresponding to every concept there is a class (some of them sets) [George/Velleman] |
| 7074 | Man is a useless passion [Sartre] |
| 6687 | Man is the desire to be God [Sartre] |
| 3843 | There is no human nature [Sartre] |
| 20762 | There are no values to justify us, and no excuses [Sartre] |
| 3852 | If values depend on us, freedom is the foundation of all values [Sartre] |
| 22228 | Sartre's freedom is not for whimsical action, but taking responsibility for our own values [Sartre, by Daigle] |
| 22233 | Love is the demand to be loved [Sartre] |
| 20764 | In becoming what we want to be we create what we think man ought to be [Sartre] |
| 3848 | Cowards are responsible for their cowardice [Sartre] |
| 20763 | When my personal freedom becomes involved, I must want freedom for everyone else [Sartre] |
| 22229 | Existentialists says that cowards and heroes make themselves [Sartre] |
| 20755 | Fear concerns the world, but 'anguish' comes from confronting my self [Sartre] |
| 3842 | Existence before essence (or begin with the subjective) [Sartre] |
| 6868 | 'Existence precedes essence' means we have no pre-existing self, but create it through existence [Sartre, by Le Poidevin] |
| 3844 | Existentialism says man is whatever he makes of himself [Sartre] |
| 22232 | Authenticity is taking responsibility for a situation, with all its risks and emotions [Sartre] |
| 20760 | Sincerity is not authenticity, because it only commits to one particular identity [Sartre, by Aho] |
| 22231 | We flee from the anguish of freedom by seeing ourselves objectively, as determined [Sartre] |
| 20754 | It is dishonest to offer passions as an excuse [Sartre] |
| 22230 | Sartre gradually realised that freedom is curtailed by the weight of situation [Sartre, by Daigle] |
| 3851 | If I do not choose, that is still a choice [Sartre] |
| 6571 | When a man must choose between his mother and the Resistance, no theory can help [Sartre, by Fogelin] |
| 20491 | States have a monopoly of legitimate violence [Sartre, by Wolff,J] |
| 21240 | The truth about events always comes from the oppressed and disadvantaged [Sartre, by Bakewell] |
| 3845 | Without God there is no intelligibility or value [Sartre] |