106 ideas
| 1887 | You cannot divide anything into many parts, because after the first division you are no longer dividing the original [Sext.Empiricus] |
| 22764 | Ordinary speech is not exact about what is true; we say we are digging a well before the well exists [Sext.Empiricus] |
| 1403 | A rational donkey would starve to death between two totally identical piles of hay [Buridan, by PG] |
| 22752 | Reasoning is impossible without a preconception [Sext.Empiricus] |
| 1885 | Proof moves from agreed premises to a non-evident inference [Sext.Empiricus] |
| 6021 | It is only when we say a proposition that we speak truly or falsely [Sext.Empiricus] |
| 12196 | A valid hypothetical syllogism is 'that which does not begin with a truth and end with a falsehood' [Sext.Empiricus] |
| 6020 | 'Man is a rational mortal animal' is equivalent to 'if something is a man, that thing is a rational mortal animal' [Sext.Empiricus] |
| 1902 | Since Socrates either died when he was alive (a contradiction) or died when he was dead (meaningless), he didn't die [Sext.Empiricus] |
| 12154 | Are 'word token' and 'word type' different sorts of countable objects, or two ways of counting? [Geach, by Perry] |
| 10735 | Abstraction from objects won't reveal an operation's being performed 'so many times' [Geach] |
| 8780 | Attributes are functions, not objects; this distinguishes 'square of 2' from 'double of 2' [Geach] |
| 8969 | We should abandon absolute identity, confining it to within some category [Geach, by Hawthorne] |
| 16678 | Without magnitude a thing would retain its parts, but they would have no location [Buridan] |
| 22744 | Parts are not parts if their whole is nothing more than the parts [Sext.Empiricus] |
| 22762 | Some properties are inseparable from a thing, such as the length, breadth and depth of a body [Sext.Empiricus] |
| 16793 | A thing is (less properly) the same over time if each part is succeeded by another [Buridan] |
| 16075 | Denial of absolute identity has drastic implications for logic, semantics and set theory [Wasserman on Geach] |
| 12152 | Identity is relative. One must not say things are 'the same', but 'the same A as' [Geach] |
| 16073 | Leibniz's Law is incomplete, since it includes a non-relativized identity predicate [Geach, by Wasserman] |
| 11910 | Being 'the same' is meaningless, unless we specify 'the same X' [Geach] |
| 1889 | If an argument has an absurd conclusion, we should not assent to the absurdity, but avoid the absurd argument [Sext.Empiricus] |
| 1871 | Whether honey is essentially sweet may be doubted, as it is a matter of judgement rather than appearance [Sext.Empiricus] |
| 16726 | Why can't we deduce secondary qualities from primary ones, if they cause them? [Buridan] |
| 1883 | How can the intellect know if sensation is reliable if it doesn't directly see external objects? [Sext.Empiricus] |
| 22748 | Some say motion is perceived by sense, but others say it is by intellect [Sext.Empiricus] |
| 1890 | We distinguish ambiguities by seeing what is useful [Sext.Empiricus] |
| 22759 | Fools, infants and madmen may speak truly, but do not know [Sext.Empiricus] |
| 20795 | Some things are their own criterion, such as straightness, a set of scales, or light [Sext.Empiricus] |
| 22760 | Madmen are reliable reporters of what appears to them [Sext.Empiricus] |
| 1870 | The basis of scepticism is the claim that every proposition has an equal opposing proposition [Sext.Empiricus] |
| 1882 | The necks of doves appear different in colour depending on the angle of viewing [Sext.Empiricus] |
| 1872 | The same tower appears round from a distance, but square close at hand [Sext.Empiricus] |
| 1873 | If we press the side of an eyeball, objects appear a different shape [Sext.Empiricus] |
| 1881 | The same oar seems bent in water and straight when out of it [Sext.Empiricus] |
| 20794 | How can sceptics show there is no criterion? Weak without, contradiction with [Sext.Empiricus] |
| 1874 | How can we judge between our impressions and those of other animals, when we ourselves are involved? [Sext.Empiricus] |
| 1876 | If we enjoy different things, presumably we receive different impressions [Sext.Empiricus] |
| 1878 | Water that seems lukewarm can seem very hot on inflamed skin [Sext.Empiricus] |
| 1877 | If we had no hearing or sight, we would assume no sound or sight exists, so there may be unsensed qualities [Sext.Empiricus] |
| 1880 | Some actions seem shameful when sober but not when drunk [Sext.Empiricus] |
| 1879 | Sickness is perfectly natural to the sick, so their natural perceptions should carry some weight [Sext.Empiricus] |
| 1910 | With us it is shameful for men to wear earrings, but among Syrians it is considered noble [Sext.Empiricus] |
| 1911 | Even if all known nations agree on a practice, there may be unknown nations which disagree [Sext.Empiricus] |
| 6026 | How can you investigate without some preconception of your object? [Sext.Empiricus] |
| 16577 | Induction is not demonstration, because not all of the instances can be observed [Buridan] |
| 16576 | Science is based on induction, for general truths about fire, rhubarb and magnets [Buridan] |
| 1886 | If you don't view every particular, you may miss the one which disproves your universal induction [Sext.Empiricus] |
| 8775 | A big flea is a small animal, so 'big' and 'small' cannot be acquired by abstraction [Geach] |
| 8776 | We cannot learn relations by abstraction, because their converse must be learned too [Geach] |
| 10732 | If concepts are just recognitional, then general judgements would be impossible [Geach] |
| 22746 | If we try to conceive of a line with no breadth, it ceases to exist, and so has no length [Sext.Empiricus] |
| 2567 | You can't define real mental states in terms of behaviour that never happens [Geach] |
| 2568 | Beliefs aren't tied to particular behaviours [Geach] |
| 22741 | The incorporeal is not in the nature of body, and so could not emerge from it [Sext.Empiricus] |
| 1884 | If we utter three steps of a logical argument, they never exist together [Sext.Empiricus] |
| 8781 | The mind does not lift concepts from experience; it creates them, and then applies them [Geach] |
| 22763 | We can only dream of a winged man if we have experienced men and some winged thing [Sext.Empiricus] |
| 10731 | For abstractionists, concepts are capacities to recognise recurrent features of the world [Geach] |
| 8769 | If someone has aphasia but can still play chess, they clearly have concepts [Geach] |
| 8770 | 'Abstractionism' is acquiring a concept by picking out one experience amongst a group [Geach] |
| 8771 | 'Or' and 'not' are not to be found in the sensible world, or even in the world of inner experience [Geach] |
| 8772 | We can't acquire number-concepts by extracting the number from the things being counted [Geach] |
| 8773 | Abstractionists can't explain counting, because it must precede experience of objects [Geach] |
| 8774 | The numbers don't exist in nature, so they cannot have been abstracted from there into our languages [Geach] |
| 8778 | Blind people can use colour words like 'red' perfectly intelligently [Geach] |
| 8777 | If 'black' and 'cat' can be used in the absence of such objects, how can such usage be abstracted? [Geach] |
| 8779 | We can form two different abstract concepts that apply to a single unified experience [Geach] |
| 10733 | The abstractionist cannot explain 'some' and 'not' [Geach] |
| 10734 | Only a judgement can distinguish 'striking' from 'being struck' [Geach] |
| 22754 | Saying the good is useful or choiceworth or happiness-creating is not the good, but a feature of it [Sext.Empiricus] |
| 22489 | 'Good' is an attributive adjective like 'large', not predicative like 'red' [Geach, by Foot] |
| 22755 | Like a warming fire, what is good by nature should be good for everyone [Sext.Empiricus] |
| 22756 | If a desire is itself desirable, then we shouldn't desire it, as achieving it destroys it [Sext.Empiricus] |
| 6032 | Right actions, once done, are those with a reasonable justification [Sext.Empiricus] |
| 1517 | The tektraktys (1+2+3+4=10) is the 'fount of ever-flowing nature' [Sext.Empiricus] |
| 1894 | Some say that causes are physical, some say not [Sext.Empiricus] |
| 1896 | If there were no causes then everything would have been randomly produced by everything [Sext.Empiricus] |
| 1897 | Knowing an effect results from a cause means knowing that the cause belongs with the effect, which is circular [Sext.Empiricus] |
| 1898 | Cause can't exist before effect, or exist at the same time, so it doesn't exist [Sext.Empiricus] |
| 1895 | Causes are either equal to the effect, or they link equally with other causes, or they contribute slightly [Sext.Empiricus] |
| 1899 | Does the original self-mover push itself from behind, or pull itself from in front? [Sext.Empiricus] |
| 22747 | A man walking backwards on a forwards-moving ship is moving in a fixed place [Sext.Empiricus] |
| 1900 | If time and place are infinitely divided, it becomes impossible for movement ever to begin [Sext.Empiricus] |
| 1901 | If all atoms, times and places are the same, everything should move with equal velocity [Sext.Empiricus] |
| 1903 | If motion and rest are abolished, so is time [Sext.Empiricus] |
| 1904 | Time must be unlimited, but past and present can't be non-existent, and can't be now, so time does not exist [Sext.Empiricus] |
| 22749 | Time doesn't end with the Universe, because tensed statements about destruction remain true [Sext.Empiricus] |
| 22750 | Time is divisible, into past, present and future [Sext.Empiricus] |
| 1905 | How can time be divisible if we can't compare one length of time with another? [Sext.Empiricus] |
| 22742 | Socrates either dies when he exists (before his death) or when he doesn't (after his death) [Sext.Empiricus] |
| 22751 | If the present is just the limit of the past or the future, it can't exist because they don't exist [Sext.Empiricus] |
| 22730 | All men agree that God is blessed, imperishable, happy and good [Sext.Empiricus] |
| 22739 | God must suffer to understand suffering [Sext.Empiricus] |
| 1891 | How can we agree on the concept of God, unless we agree on his substance or form or place? [Sext.Empiricus] |
| 22738 | The Divine must lack the virtues of continence and fortitude, because they are not needed [Sext.Empiricus] |
| 22734 | God is defended by agreement, order, absurdity of denying God, and refutations [Sext.Empiricus] |
| 1892 | The existence of God can't be self-evident or everyone would have agreed on it, so it needs demonstration [Sext.Empiricus] |
| 22736 | God's sensations imply change, and hence perishing, which is absurd, so there is no such God [Sext.Empiricus] |
| 22740 | God without virtue is absurd, but God's virtues will be better than God [Sext.Empiricus] |
| 22735 | The original substance lacked motion or shape, and was given these by a cause [Sext.Empiricus] |
| 22732 | The perfections of God were extrapolations from mankind [Sext.Empiricus] |
| 22728 | Gods were invented as watchers of people's secret actions [Sext.Empiricus] |
| 22737 | An incorporeal God could do nothing, and a bodily god would perish, so there is no God [Sext.Empiricus] |
| 22731 | It is mad to think that what is useful to us, like lakes and rivers, are gods [Sext.Empiricus] |
| 1893 | If God foresaw evil he would presumably prevent it, and if he only foresees some things, why those things? [Sext.Empiricus] |