73 ideas
23269 | Philosophy must start from clearly observed facts [Galen] |
23248 | Early empiricists said reason was just a useless concept introduced by philosophers [Galen, by Frede,M] |
5728 | The concept of truth was originated by the senses [Lucretius] |
17749 | Post proved the consistency of propositional logic in 1921 [Walicki] |
17765 | Propositional language can only relate statements as the same or as different [Walicki] |
17764 | Boolean connectives are interpreted as functions on the set {1,0} [Walicki] |
17752 | The empty set is useful for defining sets by properties, when the members are not yet known [Walicki] |
17753 | The empty set avoids having to take special precautions in case members vanish [Walicki] |
17759 | Ordinals play the central role in set theory, providing the model of well-ordering [Walicki] |
17741 | To determine the patterns in logic, one must identify its 'building blocks' [Walicki] |
17747 | A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki] |
17748 | The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki] |
17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki] |
17758 | Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki] |
17755 | Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki] |
17756 | The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki] |
17760 | Two infinite ordinals can represent a single infinite cardinal [Walicki] |
17757 | Members of ordinals are ordinals, and also subsets of ordinals [Walicki] |
17762 | In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki] |
17754 | Inductive proof depends on the choice of the ordering [Walicki] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
5702 | The senses are much the best way to distinguish true from false [Lucretius] |
5729 | If the senses are deceptive, reason, which rests on them, is even worse [Lucretius] |
5697 | The only possible standard for settling doubts is the foundation of the senses [Lucretius] |
5727 | Most supposed delusions of the senses are really misinterpretations by the mind [Lucretius] |
5714 | Even simple facts are hard to believe at first hearing [Lucretius] |
23266 | The spirit in the soul wants freedom, power and honour [Galen] |
5718 | The mind is in the middle of the breast, because there we experience fear and joy [Lucretius] |
5717 | The mind is a part of a man, just like a hand or an eye [Lucretius] |
6003 | Galen showed by experiment that the brain controls the body [Galen, by Hankinson] |
21387 | The separate elements and capacities of a mind cannot be distinguished [Lucretius] |
23219 | Stopping the heart doesn't terminate activity; pressing the brain does that [Galen, by Cobb] |
21799 | We just use the word 'faculty' when we don't know the psychological cause [Galen] |
23264 | Philosophers think faculties are in substances, and invent a faculty for every activity [Galen] |
5709 | The actions of the mind are not determinate and passive, because atoms can swerve [Lucretius] |
5695 | Only bodies can touch one another [Lucretius] |
5711 | The earth is and always has been an insentient being [Lucretius] |
5712 | Particles may have sensation, but eggs turning into chicks suggests otherwise [Lucretius] |
5719 | The mind moves limbs, wakes the body up, changes facial expressions, which involve touch [Lucretius] |
5724 | Lions, foxes and deer have distinct characters because their minds share in their bodies [Lucretius] |
23220 | The brain contains memory and reason, and is the source of sensation and decision [Galen] |
5713 | You needn't be made of laughing particles to laugh, so why not sensation from senseless seeds? [Lucretius] |
23265 | The rational part of the soul is the desire for truth, understanding and recollection [Galen] |
6611 | One man's meat is another man's poison [Lucretius] |
5730 | Our bodies weren't created to be used; on the contrary, their creation makes a use possible [Lucretius] |
5726 | The dead are no different from those who were never born [Lucretius] |
5705 | Nature only wants two things: freedom from pain, and pleasure [Lucretius] |
7453 | Galen's medicine followed the mean; each illness was balanced by opposite treatment [Galen, by Hacking] |
6030 | Each part of the soul has its virtue - pleasure for appetite, success for competition, and rectitude for reason [Galen] |
23268 | We execute irredeemable people, to protect ourselves, as a deterrent, and ending a bad life [Galen] |
5716 | Nature runs the universe by herself without the aid of gods [Lucretius] |
5704 | There can be no centre in infinity [Lucretius] |
5703 | The universe must be limitless, since there could be nothing outside to limit it [Lucretius] |
5693 | Everything is created and fed by nature from atoms, and they return to atoms in death [Lucretius] |
5701 | If an object is infinitely subdivisible, it will be the same as the whole universe [Lucretius] |
5708 | In downward motion, atoms occasionally swerve slightly for no reason [Lucretius] |
17004 | Nothing can break the binding laws of eternity [Lucretius] |
5696 | If there were no space there could be no movement, or even creation [Lucretius] |
5706 | Atoms move themselves [Lucretius] |
5700 | It is quicker to break things up than to assemble them [Lucretius] |
5698 | We can only sense time by means of movement, or its absence [Lucretius] |
5715 | This earth is very unlikely to be the only one created [Lucretius] |
5694 | Nothing can be created by divine power out of nothing [Lucretius] |
5699 | If matter wasn't everlasting, everything would have disappeared by now [Lucretius] |
5707 | The universe can't have been created by gods, because it is too imperfect [Lucretius] |
5710 | Gods are tranquil and aloof, and have no need of or interest in us [Lucretius] |
5731 | Why does Jupiter never hurl lightning from a blue sky? [Lucretius] |
5720 | Spirit is mortal [Lucretius] |
5722 | For a separated spirit to remain sentient it would need sense organs attached to it [Lucretius] |
5725 | An immortal mind couldn't work harmoniously with a mortal body [Lucretius] |
5721 | The mind is very small smooth particles, which evaporate at death [Lucretius] |
5723 | If spirit is immortal and enters us at birth, why don't we remember a previous existence? [Lucretius] |