151 ideas
| 1887 | You cannot divide anything into many parts, because after the first division you are no longer dividing the original [Sext.Empiricus] |
| 22270 | Frege changed philosophy by extending logic's ability to check the grounds of thinking [Potter on Frege] |
| 5082 | Reason grasps generalities, while the senses grasp particulars [Aristotle] |
| 8939 | We should not describe human laws of thought, but how to correctly track truth [Frege, by Fisher] |
| 1885 | Proof moves from agreed premises to a non-evident inference [Sext.Empiricus] |
| 4971 | I don't use 'subject' and 'predicate' in my way of representing a judgement [Frege] |
| 17745 | For Frege, 'All A's are B's' means that the concept A implies the concept B [Frege, by Walicki] |
| 13270 | Are a part and whole one or many? Either way, what is the cause? [Aristotle] |
| 7728 | Frege has a judgement stroke (vertical, asserting or judging) and a content stroke (horizontal, expressing) [Frege, by Weiner] |
| 16881 | The laws of logic are boundless, so we want the few whose power contains the others [Frege] |
| 7622 | In 1879 Frege developed second order logic [Frege, by Putnam] |
| 12196 | A valid hypothetical syllogism is 'that which does not begin with a truth and end with a falsehood' [Sext.Empiricus] |
| 7729 | Frege replaced Aristotle's subject/predicate form with function/argument form [Frege, by Weiner] |
| 9950 | A quantifier is a second-level predicate (which explains how it contributes to truth-conditions) [Frege, by George/Velleman] |
| 9991 | For Frege the variable ranges over all objects [Frege, by Tait] |
| 10536 | Frege's domain for variables is all objects, but modern interpretations first fix the domain [Dummett on Frege] |
| 7730 | Frege introduced quantifiers for generality [Frege, by Weiner] |
| 7742 | Frege reduced most quantifiers to 'everything' combined with 'not' [Frege, by McCullogh] |
| 13824 | Proof theory began with Frege's definition of derivability [Frege, by Prawitz] |
| 13609 | Frege produced axioms for logic, though that does not now seem the natural basis for logic [Frege, by Kaplan] |
| 1902 | Since Socrates either died when he was alive (a contradiction) or died when he was dead (meaningless), he didn't die [Sext.Empiricus] |
| 9790 | Geometry studies naturally occurring lines, but not as they occur in nature [Aristotle] |
| 22962 | Two is the least number, but there is no least magnitude, because it is always divisible [Aristotle] |
| 18090 | Without infinity time has limits, magnitudes are indivisible, and numbers come to an end [Aristotle] |
| 22929 | Aristotle's infinity is a property of the counting process, that it has no natural limit [Aristotle, by Le Poidevin] |
| 22930 | Lengths do not contain infinite parts; parts are created by acts of division [Aristotle, by Le Poidevin] |
| 18833 | A continuous line cannot be composed of indivisible points [Aristotle] |
| 17855 | It may be possible to define induction in terms of the ancestral relation [Frege, by Wright,C] |
| 9974 | Ten sheep and ten dogs are the same numerically, but it is not the same ten [Aristotle] |
| 10607 | Frege's logic has a hierarchy of object, property, property-of-property etc. [Frege, by Smith,P] |
| 11008 | Existence is not a first-order property, but the instantiation of a property [Frege, by Read] |
| 5105 | The incommensurability of the diagonal always exists, and so it is not in time [Aristotle] |
| 16115 | Change is the implied actuality of that which exists potentially [Aristotle] |
| 22960 | The sophists thought a man in the Lyceum is different from that man in the marketplace [Aristotle] |
| 17262 | Aristotle's formal and material 'becauses' [aitiai] arguably involve grounding [Aristotle, by Correia/Schnieder] |
| 16656 | The separation from here to there is not the same as the separation from there to here [Aristotle] |
| 16644 | The features of a thing (whether quality or quantity) are inseparable from their subjects [Aristotle] |
| 5117 | Heavy and light are defined by their tendency to move down or up [Aristotle] |
| 17041 | Natural objects include animals and their parts, plants, and the simple elements [Aristotle] |
| 16172 | Substance is not predicated of anything - but it still has something underlying it, that originates it [Aristotle] |
| 16623 | We only infer underlying natures by analogy, observing bronze of a statue, or wood of a bed [Aristotle] |
| 16174 | A nature is related to a substance as shapeless matter is to something which has a shape [Aristotle] |
| 17043 | Form, not matter, is a thing's nature, because it is actual, rather than potential [Aristotle] |
| 16970 | A thing's form and purpose are often the same, and form can be the initiator of change too [Aristotle] |
| 16104 | Unity of the form is just unity of the definition [Aristotle] |
| 11255 | In feature-generation the matter (such as bronze) endures, but in generation it doesn't [Aristotle, by Politis] |
| 9071 | We first sense whole entities, and then move to particular parts of it [Aristotle] |
| 16791 | There is no whole except for the parts [Aristotle] |
| 16972 | The four explanations are the main aspects of a thing's nature [Aristotle, by Moravcsik] |
| 5084 | A thing's nature is what causes its changes and stability [Aristotle] |
| 16173 | Coming to be is by shape-change, addition, subtraction, composition or alteration [Aristotle] |
| 17042 | Natural things are their own source of stability through change [Aristotle] |
| 16691 | A day, or the games, has one thing after another, actually and potentially occurring [Aristotle] |
| 16574 | Coming-to-be may be from nothing in a qualified way, as arising from an absence [Aristotle] |
| 11254 | Matter is potentiality [Aristotle, by Politis] |
| 13110 | Intrinsic cause is prior to coincidence, so nature and intelligence are primary causes, chance secondary [Aristotle] |
| 13106 | Maybe there is no pure chance; a man's choices cause his chance meetings [Aristotle] |
| 13108 | Chance is a coincidental cause among events involving purpose and choice [Aristotle] |
| 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] |
| 1883 | How can the intellect know if sensation is reliable if it doesn't directly see external objects? [Sext.Empiricus] |
| 1890 | We distinguish ambiguities by seeing what is useful [Sext.Empiricus] |
| 8331 | To know something we need understanding, which is grasp of the primary cause [Aristotle] |
| 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] |
| 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] |
| 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] |
| 1877 | If we had no hearing or sight, we would assume no sound or sight exists, so there may be unsensed qualities [Sext.Empiricus] |
| 1878 | Water that seems lukewarm can seem very hot on inflamed skin [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] |
| 1886 | If you don't view every particular, you may miss the one which disproves your universal induction [Sext.Empiricus] |
| 5080 | We know a thing if we grasp its first causes, principles and basic elements [Aristotle] |
| 16969 | Science refers the question Why? to four causes/explanations: matter, form, source, purpose [Aristotle] |
| 11250 | Four Explanations: the essence and form; the matter; the source; and the end [Aristotle, by Politis] |
| 12045 | Aristotle's four 'causes' are four items which figure in basic explanations of nature [Aristotle, by Annas] |
| 16968 | There are as many causes/explanations as there are different types of why-question [Aristotle] |
| 13109 | Chance is inexplicable, because we can only explain what happens always or usually [Aristotle] |
| 1884 | If we utter three steps of a logical argument, they never exist together [Sext.Empiricus] |
| 9789 | You can't abstract natural properties to make Forms - objects and attributes are defined together [Aristotle] |
| 9788 | Mathematicians study what is conceptually separable, and doesn't lead to error [Aristotle] |
| 5107 | Predicates are substance, quality, place, relation, quantity and action or affection [Aristotle] |
| 22280 | Frege's account was top-down and decompositional, not bottom-up and compositional [Frege, by Potter] |
| 20042 | We assign the cause of someone's walking when we say why they are doing it [Aristotle] |
| 5110 | Goodness is when a thing (such as a circle) is complete, and conforms with its nature [Aristotle] |
| 5111 | All moral virtue is concerned with bodily pleasure and pain [Aristotle] |
| 5092 | Nature is a principle of change, so we must understand change first [Aristotle] |
| 5113 | Nothing natural is disorderly, because nature is responsible for all order [Aristotle] |
| 5085 | 'Nature' refers to two things - form and matter [Aristotle] |
| 5089 | Nature has purpose, and aims at what is better. Is it coincidence that crops grow when it rains? [Aristotle] |
| 5086 | The nature of a thing is its end and purpose [Aristotle] |
| 5087 | A thing's purpose is ambiguous, and from one point of view we ourselves are ends [Aristotle] |
| 5091 | Teeth and crops are predictable, so they cannot be mere chance, but must have a purpose [Aristotle] |
| 5108 | Is ceasing-to-be unnatural if it happens by force, and natural otherwise? [Aristotle] |
| 5093 | Continuity depends on infinity, because the continuous is infinitely divisible [Aristotle] |
| 5095 | The heavens seem to be infinite, because we cannot imagine their end [Aristotle] |
| 16762 | Matter desires form, as female desires male, and ugliness desires beauty [Aristotle] |
| 17464 | When Aristotle's elements compound they are stable, so why would they ever separate? [Weisberg/Needham/Hendry on Aristotle] |
| 11252 | The 'form' of a thing explains why the matter constitutes that particular thing [Aristotle, by Politis] |
| 11253 | A 'material' cause/explanation is the form of whatever is the source [Aristotle, by Politis] |
| 13107 | Causes produce a few things in their own right, and innumerable things coincidentally [Aristotle] |
| 8332 | The four causes are the material, the form, the source, and the end [Aristotle] |
| 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] |
| 9787 | Scientists must know the essential attributes of the things they study [Aristotle] |
| 20063 | Motion fulfils potentiality [Aristotle] |
| 5114 | If movement can arise within an animal, why can't it also arise in the universe? [Aristotle] |
| 1899 | Does the original self-mover push itself from behind, or pull itself from in front? [Sext.Empiricus] |
| 5116 | When there is unnatural movement (e.g. fire going downwards) the cause is obvious [Aristotle] |
| 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] |
| 5099 | The universe as a whole is not anywhere [Aristotle] |
| 5097 | If everything has a place, this causes an infinite regress, because each place must have place [Aristotle] |
| 5098 | Place is not shape, or matter, or extension between limits; it is the limits of a body [Aristotle] |
| 20920 | If there were many cosmoses, each would have its own time, giving many times [Aristotle] |
| 1903 | If motion and rest are abolished, so is time [Sext.Empiricus] |
| 5106 | Would there be time if there were no mind? [Aristotle] |
| 22967 | It is unclear whether time depends on the existence of soul [Aristotle] |
| 8590 | Time does not exist without change [Aristotle] |
| 22965 | Time measures rest, as well as change [Aristotle] |
| 22885 | For Aristotle time is not a process but a means for measuring processes [Aristotle, by Bardon] |
| 22959 | Time is not change, but the number we associate with change [Aristotle] |
| 22964 | Change only exists in time through its being temporally measure [Aristotle] |
| 5104 | Time is an aspect of change [Aristotle] |
| 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] |
| 22956 | How can time exist, when it is composed of what has ceased to be and is yet to be? [Aristotle] |
| 5102 | If all of time has either ceased to exist, or has not yet happened, maybe time does not exist [Aristotle] |
| 5103 | Time is not change, but requires change in our minds to be noticed [Aristotle] |
| 22961 | The present moment is obviously a necessary feature of time [Aristotle] |
| 22916 | Unlike time, change goes at different rates, and is usually localised [Aristotle, by Le Poidevin] |
| 16693 | Time has parts, but the now is not one of them, and time is not composed of nows [Aristotle] |
| 22958 | Nows can't be linked together, any more than points on a line [Aristotle] |
| 1905 | How can time be divisible if we can't compare one length of time with another? [Sext.Empiricus] |
| 22968 | Circular motion is the most obvious measure of time, and especially the celestial sphere [Aristotle] |
| 22963 | We measure change by time, and time by change, as they are interdefined [Aristotle] |
| 22966 | The present moment is a link (of past to future), and also a limit (of past and of future) [Aristotle] |
| 22957 | We can't tell whether the changing present moment is one thing, or a succession of things [Aristotle] |
| 5083 | Do things come to be from what is, or from what is not? Both seem problematical. [Aristotle] |
| 5119 | The source of all movement must be indivisible and have no magnitude [Aristotle] |
| 1891 | How can we agree on the concept of God, unless we agree on his substance or form or place? [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] |
| 7741 | The predicate 'exists' is actually a natural language expression for a quantifier [Frege, by Weiner] |
| 1893 | If God foresaw evil he would presumably prevent it, and if he only foresees some things, why those things? [Sext.Empiricus] |