67 ideas
| 18450 | Philosophy has its own mode of death, by separating soul from body [Porphyry] |
| 9123 | Someone standing in a doorway seems to be both in and not-in the room [Priest,G, by Sorensen] |
| 8368 | A correct definition is what can be substituted without loss of meaning [Ducasse] |
| 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] |
| 18451 | The presence of the incorporeal is only known by certain kinds of disposition [Porphyry] |
| 15034 | Are genera and species real or conceptual? bodies or incorporeal? in sensibles or separate from them? [Porphyry] |
| 18459 | Diversity arises from the power of unity [Porphyry] |
| 18452 | Memory is not conserved images, but reproduction of previous thought [Porphyry] |
| 18453 | Intelligence is aware of itself, so the intelligence is both the thinker and the thought [Porphyry] |
| 18462 | The soul is everywhere and nowhere in the body, and must be its cause [Porphyry] |
| 18463 | Successful introspection reveals the substrate along with the object of thought [Porphyry] |
| 18458 | The soul is bound to matter by the force of its own disposition [Porphyry] |
| 18464 | Justice is each person fulfilling his function [Porphyry] |
| 18448 | We should avoid the pleasures of love, or at least, should not enact our dreams [Porphyry] |
| 18444 | Civil virtues make us behave benevolently, and thereby unite citizens [Porphyry] |
| 18445 | Civil virtues control the passions, and make us conform to our nature [Porphyry] |
| 18446 | Purificatory virtues detach the soul completely from the passions [Porphyry] |
| 18447 | There are practical, purificatory, contemplative, and exemplary virtues [Porphyry] |
| 18456 | Unified real existence is neither great nor small, though greatness and smallness participate in it [Porphyry] |
| 8367 | Causation is defined in terms of a single sequence, and constant conjunction is no part of it [Ducasse] |
| 8372 | We see what is in common between causes to assign names to them, not to perceive them [Ducasse] |
| 8369 | Causes are either sufficient, or necessary, or necessitated, or contingent upon [Ducasse] |
| 8373 | When a brick and a canary-song hit a window, we ignore the canary if we are interested in the breakage [Ducasse] |
| 8370 | A cause is a change which occurs close to the effect and just before it [Ducasse] |
| 8371 | Recurrence is only relevant to the meaning of law, not to the meaning of cause [Ducasse] |
| 8374 | We are interested in generalising about causes and effects purely for practical purposes [Ducasse] |
| 18454 | Time is the circular movement of the soul [Porphyry] |
| 18455 | Some think time is seen at rest, as well as in movement [Porphyry] |
| 18460 | God is nowhere, and hence everywhere [Porphyry] |
| 18461 | Everything existing proceeds from divinity, and is within divinity [Porphyry] |
| 18449 | Nature binds or detaches body to soul, but soul itself joins and detaches soul from body [Porphyry] |
| 18457 | Individual souls are all connected, though distinct, and without dividing universal Soul [Porphyry] |