53 ideas
1887 | You cannot divide anything into many parts, because after the first division you are no longer dividing the original [Sext.Empiricus] |
Full Idea: You cannot divide anything (such as the decad) into many parts, because as soon as you separate the first part, you are no longer dividing the original. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.215) |
1885 | Proof moves from agreed premises to a non-evident inference [Sext.Empiricus] |
Full Idea: Dogmatists define proof as "an argument which, by means of agreed premises, reveals by way of deduction a nonevident inference". | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.135) |
12196 | A valid hypothetical syllogism is 'that which does not begin with a truth and end with a falsehood' [Sext.Empiricus] |
Full Idea: Philo (of Megara) says that a valid hypothetical syllogism is 'that which does not begin with a truth and end with a falsehood,' as for instance the syllogism 'If it is day, I converse,' when in fact it is day and I am conversing. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.110) | |
A reaction: Russell endorses this, and Rumfitt quotes it as the classic case of denying that there is any modal aspect (such as 'logical necessity') involved in logical consequence. He labels it 'material or Philonian consequence'. |
17867 | If a concept is not compact, it will not be presentable to finite minds [Almog] |
Full Idea: If the notion of 'logically following' in your language is not compact, it will not be locally presentable to finite minds. | |
From: Joseph Almog (Nature Without Essence [2010], 02) |
1902 | Since Socrates either died when he was alive (a contradiction) or died when he was dead (meaningless), he didn't die [Sext.Empiricus] |
Full Idea: If Socrates died, he died either when he lived or when he died; so he was either dead when he was alive, or he was twice dead when he was dead. So he didn't die. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.111) | |
A reaction: One of my favourites. Of all the mysteries facing us, the one that boggles me most is how anything can happen in the 'present' moment, if the present is just the overlap point between past and future. |
17877 | The number series is primitive, not the result of some set theoretic axioms [Almog] |
Full Idea: On Skolem's account, to 'get' the natural numbers - that primal structure - do not 'look for it' as the satisfier of some abstract (set-theoretic) axiomatic essence; start with that primitive structure. | |
From: Joseph Almog (Nature Without Essence [2010], 12) | |
A reaction: [Skolem 1922 and 1923] Almog says the numbers are just 0,1,2,3,4..., and not some underlying axioms. That makes it sound as if they have nothing in common, and that the successor relation is a coincidence. |
17872 | Definitionalists rely on snapshot-concepts, instead of on the real processes [Almog] |
Full Idea: The definitionalist errs by abstracting away from differences cosmic processes, freezing real, dynamic processes in snapshot-concepts. | |
From: Joseph Almog (Nature Without Essence [2010], 08) | |
A reaction: You could hardly do science at all if you didn't 'abstract away from the differences in cosmic processes'. We can't write about sea-waves, because they all differ slightly? 'Electron' is a snapshot concept. |
17871 | Fregean meanings are analogous to conceptual essence, defining a kind [Almog] |
Full Idea: Ever since Frege, semantic definitionalists have posited a meaning ('sinn') for a name; the meaning/sinn is their semantic analog to the conceptual essence, as ontologically defining of the kind. | |
From: Joseph Almog (Nature Without Essence [2010], 07) |
17866 | Essential definition aims at existence conditions and structural truths [Almog] |
Full Idea: The essentialist encapsulating formula is meant to be existence-exhaustive (an attribute the satisfaction of which is logically necessary and sufficient to be the thing) and truth-exhaustive (promising all the structural truths). | |
From: Joseph Almog (Nature Without Essence [2010], 01) | |
A reaction: [compressed] If he thinks essentialism means that one short phrase can achieve all this, then it is not surprising that Almog renounces his former essentialism in this essay. He may, however, have misunderstood. He should reread Aristotle. |
17868 | Surface accounts aren't exhaustive as they always allow unintended twin cases [Almog] |
Full Idea: A surface-functional characterisation is not exhaustive. It allows unintended twins, alien intruders with different structures - water lookalikes that are not H2O and lookalike infinite structures that are not the natural numbers. | |
From: Joseph Almog (Nature Without Essence [2010], 03) | |
A reaction: He rests this on the claim in mathematical logic that fully expressive systems are always non-categorical (having unintended twins). Set theory is not fully categorical, but Peano Arithmetic is. Almog's main anti-essentialist argument. |
17870 | Alien 'tigers' can't be tigers if they are not related to our tigers [Almog] |
Full Idea: Animals roaming jungles on some planet at the other end of the galaxy with the tiger-look and the tiger genetic make-up but with a disjoint evolutionary history are not the same species as the earthly tigers. | |
From: Joseph Almog (Nature Without Essence [2010], 10) | |
A reaction: I disagree. If two independent cultures build boats, they are both boats. If we manufacture a tiger which can breed with other tigers, we've made a tiger. His 'tigers' would scream for explanation, precisely because they are tigers. If not, no puzzle. |
17869 | Kripke and Putnam offer an intermediary between real and nominal essences [Almog] |
Full Idea: Kripke and Putnam offer us enhanced essences, still formulable in one short sentence and locally graspable. They offer between Locke's mind-boggling definitive real essence and his mind-friendly but not definitive nominal essence. | |
From: Joseph Almog (Nature Without Essence [2010], 04) | |
A reaction: The solution is to add a 'deep structure' which serves both ends. |
17876 | Individual essences are just cobbled together classificatory predicates [Almog] |
Full Idea: The key for the essentialist is classificatory predication. It is only a subsequent extension of this prime idea that leads us to cobble together enough such essential predications to make an individuative essential property. | |
From: Joseph Almog (Nature Without Essence [2010], 11) | |
A reaction: So the essence is just a cross-reference of all the ways we can think of to classify it? I don't think so. Which are the essential classifications? |
13768 | Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington] |
Full Idea: If your interest in logic is confined to applications to mathematics or other a priori matters, it is fine for validity to preserve certainty, ..but if you use conditionals when arguing about contingent matters, then great caution will be required. | |
From: Dorothy Edgington (Conditionals [2001], 17.2.1) |
13770 | There are many different conditional mental states, and different conditional speech acts [Edgington] |
Full Idea: As well as conditional beliefs, there are conditional desires, hopes, fears etc. As well as conditional statements, there are conditional commands, questions, offers, promises, bets etc. | |
From: Dorothy Edgington (Conditionals [2001], 17.3.4) |
13764 | Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington] |
Full Idea: Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? Are they non-truth-functional, like 'because' or 'before'? Do the values of A and B, in some cases, leave open the value of 'If A,B'? | |
From: Dorothy Edgington (Conditionals [2001], 17.1) | |
A reaction: I would say they are not truth-functional, because the 'if' asserts some further dependency relation that goes beyond the truth or falsity of A and B. Logical ifs, causal ifs, psychological ifs... The material conditional ⊃ is truth-functional. |
13765 | 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington] |
Full Idea: If it were possible to have A true, B false, and If A,B true, it would be unsafe to infer B from A and If A,B: modus ponens would thus be invalid. Hence 'If A,B' must entail ¬(A & ¬B). | |
From: Dorothy Edgington (Conditionals [2001], 17.1) | |
A reaction: This is a firm defence of part of the truth-functional view of conditionals, and seems unassailable. The other parts of the truth table are open to question, though, if A is false, or they are both true. |
1889 | If an argument has an absurd conclusion, we should not assent to the absurdity, but avoid the absurd argument [Sext.Empiricus] |
Full Idea: If an argument leads to confessedly absurd conclusions, we should not assent to the absurdity just because of the argument, but avoid the argument because of the absurdity. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.252) | |
A reaction: cf. G.E.Moore. Denying that you have a hand seems to be an absurdity, but I'm not sure if I can give a criterion for absurdity in such a case. One person's modus ponens is another person's modus tollens. |
1871 | Whether honey is essentially sweet may be doubted, as it is a matter of judgement rather than appearance [Sext.Empiricus] |
Full Idea: Honey appears to sceptics to be sweet, but whether it is also sweet in its essence is for us a matter of doubt, since this is not an appearance but a judgement. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.20) |
1883 | How can the intellect know if sensation is reliable if it doesn't directly see external objects? [Sext.Empiricus] |
Full Idea: Just as you can't know if a portrait of Socrates is good without seeing the man, so when the intellect gazes on sensations but not the external objects it cannot know whether they are similar. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.75) |
1890 | We distinguish ambiguities by seeing what is useful [Sext.Empiricus] |
Full Idea: It is the experience of what is useful in each affair that brings about the distinguishing of ambiguities. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.258) |
1870 | The basis of scepticism is the claim that every proposition has an equal opposing proposition [Sext.Empiricus] |
Full Idea: The main basic principle of the sceptic system is that of opposing to every proposition an equal proposition. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.12) |
1882 | The necks of doves appear different in colour depending on the angle of viewing [Sext.Empiricus] |
Full Idea: The necks of doves appear different in hue according to the differences in the angle of inclination. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.120) |
1881 | The same oar seems bent in water and straight when out of it [Sext.Empiricus] |
Full Idea: The same oar seems bent when in the water but straight when out of the water. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.119) |
1873 | If we press the side of an eyeball, objects appear a different shape [Sext.Empiricus] |
Full Idea: When we press the eyeball at one side the forms, figures and sizes of the objects appear oblong and narrow. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.47) |
1872 | The same tower appears round from a distance, but square close at hand [Sext.Empiricus] |
Full Idea: The same tower appears round from a distance, but square close at hand. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.32) |
1874 | How can we judge between our impressions and those of other animals, when we ourselves are involved? [Sext.Empiricus] |
Full Idea: We cannot judge between our own impressions and those of other animals, because we ourselves are involved in the dispute. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.59) |
1880 | Some actions seem shameful when sober but not when drunk [Sext.Empiricus] |
Full Idea: Actions which seem shameful to us when sober do not seem shameful when drunk. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.109) |
1876 | If we enjoy different things, presumably we receive different impressions [Sext.Empiricus] |
Full Idea: The enjoyment of different things is an indication that we get varying impressions from the underlying objects. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.80) |
1878 | Water that seems lukewarm can seem very hot on inflamed skin [Sext.Empiricus] |
Full Idea: The same water which seems very hot when poured on inflamed spots seems lukewarm to us. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.101) |
1877 | If we had no hearing or sight, we would assume no sound or sight exists, so there may be unsensed qualities [Sext.Empiricus] |
Full Idea: A man with touch, taste and smell, but no hearing or sight, will assume nothing audible or visible exists, so maybe an apple has qualities which we have no senses to perceive. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.96) |
1879 | Sickness is perfectly natural to the sick, so their natural perceptions should carry some weight [Sext.Empiricus] |
Full Idea: Health is natural for the healthy but unnatural for the sick, and sickness is unnatural for the healthy but natural for the sick, so we must give credence to the natural perceptions of the sick. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.103) |
1910 | With us it is shameful for men to wear earrings, but among Syrians it is considered noble [Sext.Empiricus] |
Full Idea: It is a shameful thing with us for men to wear earrings, but among some of the barbarians, such as the Syrians, it is a token of nobility. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.203) |
1911 | Even if all known nations agree on a practice, there may be unknown nations which disagree [Sext.Empiricus] |
Full Idea: Even among practices on which all known cultures are agreed, disagreement about them may possibly exist amongst some of the nations which are unknown to us. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.234) |
1886 | If you don't view every particular, you may miss the one which disproves your universal induction [Sext.Empiricus] |
Full Idea: Induction cannot establish the universal by means of the particular, since limited particulars may omit crucial examples which disprove the universal, and infinite particulars are impossible to know. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.204) |
1884 | If we utter three steps of a logical argument, they never exist together [Sext.Empiricus] |
Full Idea: If we say "If day exists, lights exists", and then "day exists", and then "light exists", then parts of the judgement never exist together, and so the whole judgement will have no real existence. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], II.109) |
17873 | Water must be related to water, just as tigers must be related to tigers [Almog] |
Full Idea: It is a blindspot to say that to be a tiger one must come from tigers, but to be water one needn't come from water. ...The error lies in not appreciating that to be water one still must come from somewhere in the cosmos, indeed, from hydrogen and oxygen. | |
From: Joseph Almog (Nature Without Essence [2010], 09) | |
A reaction: A unified picture is indeed desirable, but a better solution is to say that the essence of a tiger is in its structure, not in its origins. There are many ways to produce an artefact. There could be many ways to produce a tiger. |
1894 | Some say that causes are physical, some say not [Sext.Empiricus] |
Full Idea: Some affirm cause to be corporeal, some incorporeal. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.14) |
1897 | Knowing an effect results from a cause means knowing that the cause belongs with the effect, which is circular [Sext.Empiricus] |
Full Idea: To know an effect belongs to a cause, we must also know that that cause belongs to that effect, and this is circular. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.21) |
1898 | Cause can't exist before effect, or exist at the same time, so it doesn't exist [Sext.Empiricus] |
Full Idea: If cause neither subsists before its effect, nor subsists along with it, nor does the effect precede the cause, it would seem that it has no substantial existence at all. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.27) |
1896 | If there were no causes then everything would have been randomly produced by everything [Sext.Empiricus] |
Full Idea: If causes were non-existent everything would have been produced by everything, and at random. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.18) |
1895 | Causes are either equal to the effect, or they link equally with other causes, or they contribute slightly [Sext.Empiricus] |
Full Idea: The majority say causes are immediate (when they are directly proportional to effects), or associate (making an equal contribution to effects), or cooperant (making a slight contribution). | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.15) |
17864 | Defining an essence comes no where near giving a thing's nature [Almog] |
Full Idea: The natures of things are neither exhausted nor even partially given by 'defining essences'. | |
From: Joseph Almog (Nature Without Essence [2010], Intro) | |
A reaction: A better criticism of essentialism. 'Natures' is a much vaguer word than 'essences', however, because the latter refers to what is stable and important, whereas natures could include any aspect. Being ticklish is in my nature, but not in my essence. |
17863 | Essences promise to reveal reality, but actually drive us away from it [Almog] |
Full Idea: The essentialist line (one I trace to Aristotle, Descartes and Kripke) is driving us away from, not closer to, the real nature of things. It promised a sort of Hubble telescope - essences - able to reveal the deep structure of reality. | |
From: Joseph Almog (Nature Without Essence [2010], Intro) | |
A reaction: I suspect this is tilting at a straw man. No one thinks we should hunt for essences instead of doing normal science. 'Essence' just labels what you've got when you succeed. |
1900 | If time and place are infinitely divided, it becomes impossible for movement ever to begin [Sext.Empiricus] |
Full Idea: If bodies, and the places and times when they are said to move, are divided into infinity, motion will not occur, it being impossible to find anything which will initiate the first movement. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.76) |
1901 | If all atoms, times and places are the same, everything should move with equal velocity [Sext.Empiricus] |
Full Idea: If objects are reducible to atoms, and each thing passes in an atomic time with its own first atom into an atomic point of space, then all moving things are of equal velocity. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.77) |
1899 | Does the original self-mover push itself from behind, or pull itself from in front? [Sext.Empiricus] |
Full Idea: Self-movement must move in some particular direction, but if it pushes it will be behind itself, and if it pulls it will be in front of itself. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.68) | |
A reaction: This is the same as Aquinas's First Way of proving God's existence. |
1903 | If motion and rest are abolished, so is time [Sext.Empiricus] |
Full Idea: Since time does not seem to subsist without motion or even rest, if motion is abolished, and likewise rest, time is abolished. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.141) |
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] |
Full Idea: There can't be a time when there was no time, so time is not limited; but unlimited time means past and present are non-existent (so time is limited to the present), or they exist (which means they are present). Time does not exist. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.142) |
1905 | How can time be divisible if we can't compare one length of time with another? [Sext.Empiricus] |
Full Idea: Time is clearly divisible (into past, present and future), but it can't be, because a divisible thing is measured by some part of itself (divisions of length), but the two parts must coincide to make the measurement (e.g. present must coincide with past). | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.143) |
1891 | How can we agree on the concept of God, unless we agree on his substance or form or place? [Sext.Empiricus] |
Full Idea: How shall we be able to reach a conception of God when we have no agreement about his substance or his form or his place of abode? | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.3) |
1892 | The existence of God can't be self-evident or everyone would have agreed on it, so it needs demonstration [Sext.Empiricus] |
Full Idea: The existence of God is not pre-evident, for if it was the dogmatists would have agreed about it, whereas their disagreements show it is non-evident, and in need of demonstration. | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.6) |
1893 | If God foresaw evil he would presumably prevent it, and if he only foresees some things, why those things? [Sext.Empiricus] |
Full Idea: If God had forethought for all, there would be no evil in the world, yet they say the world is full of evil. And if he forethinks some things, why those and not others? | |
From: Sextus Empiricus (Outlines of Pyrrhonism [c.180], III.9) |