64 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] |
| 10455 | Free logic at least allows empty names, but struggles to express non-existence [Bach] |
| 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] |
| 10454 | In first-order we can't just assert existence, and it is very hard to deny something's existence [Bach] |
| 10453 | In logic constants play the role of proper names [Bach] |
| 10452 | Proper names can be non-referential - even predicate as well as attributive uses [Bach] |
| 10456 | Millian names struggle with existence, empty names, identities and attitude ascription [Bach] |
| 10440 | An object can be described without being referred to [Bach] |
| 10444 | Definite descriptions can be used to refer, but are not semantically referential [Bach] |
| 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] |
| 12900 | How could 'S knows he has hands' not have a fixed content? [Bach] |
| 12901 | If contextualism is right, knowledge sentences are baffling out of their context [Bach] |
| 12902 | Sceptics aren't changing the meaning of 'know', but claiming knowing is tougher than we think [Bach] |
| 10446 | Fictional reference is different inside and outside the fiction [Bach] |
| 10447 | We can refer to fictional entities if they are abstract objects [Bach] |
| 10443 | You 'allude to', not 'refer to', an individual if you keep their identity vague [Bach] |
| 10439 | What refers: indefinite or definite or demonstrative descriptions, names, indexicals, demonstratives? [Bach] |
| 10441 | If we can refer to things which change, we can't be obliged to single out their properties [Bach] |
| 10442 | We can think of an individual without have a uniquely characterizing description [Bach] |
| 10445 | It can't be real reference if it could refer to some other thing that satisfies the description [Bach] |
| 10457 | Since most expressions can be used non-referentially, none of them are inherently referential [Bach] |
| 10463 | Just alluding to or describing an object is not the same as referring to it [Bach] |
| 10459 | Context does not create reference; it is just something speakers can exploit [Bach] |
| 10460 | 'That duck' may not refer to the most obvious one in the group [Bach] |
| 10461 | What a pronoun like 'he' refers back to is usually a matter of speaker's intentions [Bach] |
| 10462 | Information comes from knowing who is speaking, not just from interpretation of the utterance [Bach] |
| 10458 | People slide from contextual variability all the way to contextual determination [Bach] |
| 4787 | Causation interaction is an exchange of conserved quantities, such as mass, energy or charge [Dowe, by Psillos] |
| 14586 | Physical causation consists in transference of conserved quantities [Dowe, by Mumford/Anjum] |
| 4788 | Dowe commends the Conserved Quantity theory as it avoids mention of counterfactuals [Dowe, by Psillos] |