70 ideas
| 9123 | Someone standing in a doorway seems to be both in and not-in the room [Priest,G, by Sorensen] |
| 8720 | A logic is 'relevant' if premise and conclusion are connected, and 'paraconsistent' allows contradictions [Priest,G, by Friend] |
| 9672 | Free logic is one of the few first-order non-classical logics [Priest,G] |
| 9697 | X1 x X2 x X3... x Xn indicates the 'cartesian product' of those sets [Priest,G] |
| 9685 | <a,b&62; is a set whose members occur in the order shown [Priest,G] |
| 9675 | a ∈ X says a is an object in set X; a ∉ X says a is not in X [Priest,G] |
| 9674 | {x; A(x)} is a set of objects satisfying the condition A(x) [Priest,G] |
| 9673 | {a1, a2, ...an} indicates that a set comprising just those objects [Priest,G] |
| 9677 | Φ indicates the empty set, which has no members [Priest,G] |
| 9676 | {a} is the 'singleton' set of a (not the object a itself) [Priest,G] |
| 9679 | X⊂Y means set X is a 'proper subset' of set Y [Priest,G] |
| 9678 | X⊆Y means set X is a 'subset' of set Y [Priest,G] |
| 9681 | X = Y means the set X equals the set Y [Priest,G] |
| 9683 | X ∩ Y indicates the 'intersection' of sets X and Y, the objects which are in both sets [Priest,G] |
| 9682 | X∪Y indicates the 'union' of all the things in sets X and Y [Priest,G] |
| 9684 | Y - X is the 'relative complement' of X with respect to Y; the things in Y that are not in X [Priest,G] |
| 9694 | The 'relative complement' is things in the second set not in the first [Priest,G] |
| 9693 | The 'intersection' of two sets is a set of the things that are in both sets [Priest,G] |
| 9692 | The 'union' of two sets is a set containing all the things in either of the sets [Priest,G] |
| 9698 | The 'induction clause' says complex formulas retain the properties of their basic formulas [Priest,G] |
| 9695 | An 'ordered pair' (or ordered n-tuple) is a set with its members in a particular order [Priest,G] |
| 9696 | A 'cartesian product' of sets is the set of all the n-tuples with one member in each of the sets [Priest,G] |
| 9686 | A 'set' is a collection of objects [Priest,G] |
| 9689 | The 'empty set' or 'null set' has no members [Priest,G] |
| 9690 | A set is a 'subset' of another set if all of its members are in that set [Priest,G] |
| 9691 | A 'proper subset' is smaller than the containing set [Priest,G] |
| 9688 | A 'singleton' is a set with only one member [Priest,G] |
| 9687 | A 'member' of a set is one of the objects in the set [Priest,G] |
| 9680 | The empty set Φ is a subset of every set (including itself) [Priest,G] |
| 13373 | Typically, paradoxes are dealt with by dividing them into two groups, but the division is wrong [Priest,G] |
| 13368 | The 'least indefinable ordinal' is defined by that very phrase [Priest,G] |
| 13370 | 'x is a natural number definable in less than 19 words' leads to contradiction [Priest,G] |
| 13369 | By diagonalization we can define a real number that isn't in the definable set of reals [Priest,G] |
| 13366 | The least ordinal greater than the set of all ordinals is both one of them and not one of them [Priest,G] |
| 13367 | The next set up in the hierarchy of sets seems to be both a member and not a member of it [Priest,G] |
| 13371 | If you know that a sentence is not one of the known sentences, you know its truth [Priest,G] |
| 13372 | There are Liar Pairs, and Liar Chains, which fit the same pattern as the basic Liar [Priest,G] |
| 20589 | Maybe a person's true self is their second-order desires [Tuckness/Wolf] |
| 20583 | If maximising pleasure needs measurement, so does fulfilling desires [Tuckness/Wolf] |
| 20584 | Desire satisfaction as the ideal is confused, because we desire what we judge to be good [Tuckness/Wolf] |
| 20598 | In a democracy, which 'people' are included in the decision process? [Tuckness/Wolf] |
| 20614 | People often have greater attachment to ethnic or tribal groups than to the state [Tuckness/Wolf] |
| 20596 | For global justice, adopt rules without knowing which country you will inhabit [Tuckness/Wolf] |
| 20593 | The veil of ignorance ensures both fairness and unanimity [Tuckness/Wolf] |
| 20608 | Unjust institutions may be seen as just; are they legitimate if just but seen as unjust? [Tuckness/Wolf] |
| 20597 | If winning elections depends on wealth, we have plutocracy instead of democracy [Tuckness/Wolf] |
| 20606 | Epistemic theories defend democracy as more likely to produce the right answer [Tuckness/Wolf] |
| 20600 | Which areas of public concern should be decided democratically, and which not? [Tuckness/Wolf] |
| 20609 | If several losing groups would win if they combine, a runoff seems called for [Tuckness/Wolf] |
| 20605 | Rights as interests (unlike rights as autonomy) supports mandatory voting [Tuckness/Wolf] |
| 20599 | How should democratic votes be aggregated? Can some person's votes count for more? [Tuckness/Wolf] |
| 20601 | Discussion before voting should be an essential part of democracy [Tuckness/Wolf] |
| 20613 | We have obligations to our family, even though we didn't choose its members [Tuckness/Wolf] |
| 20586 | Free speech does not include the right to shout 'Fire!' in a crowded theatre [Tuckness/Wolf] |
| 20587 | Most people want equality because they want a flourishing life [Tuckness/Wolf] |
| 20591 | If there is no suffering, wealth inequalities don't matter much [Tuckness/Wolf] |
| 20602 | Some rights are 'claims' that other people should act in a certain way [Tuckness/Wolf] |
| 20604 | Choice theory says protecting individual autonomy is basic (but needs to cover infants and animals) [Tuckness/Wolf] |
| 20603 | One theory (fairly utilitarian) says rights protect interests (but it needs to cover trivial interests) [Tuckness/Wolf] |
| 20607 | Having a right does not entail further rights needed to implement it [Tuckness/Wolf] |
| 20612 | If being subject to the law resembles a promise, we are morally obliged to obey it [Tuckness/Wolf] |
| 20611 | If others must obey laws that we like, we must obey laws that they like? [Tuckness/Wolf] |
| 20610 | Instead of against natural law, we might assess unjust laws against the values of the culture [Tuckness/Wolf] |
| 20617 | How should the punishment fit the crime (for stealing chickens?) [Tuckness/Wolf] |
| 20615 | Just wars: resist aggression, done on just cause, proportionate, last resort, not futile, legal [Tuckness/Wolf] |
| 20616 | During wars: proportional force, fair targets, fair weapons, safe prisoners, no reprisals [Tuckness/Wolf] |
| 20620 | If minority views are accepted in debate, then religious views must be accepted [Tuckness/Wolf] |
| 20619 | Is abortion the ending of a life, or a decision not to start one? [Tuckness/Wolf] |
| 1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
| 5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |