display all the ideas for this combination of philosophers
49 ideas
| 5114 | If movement can arise within an animal, why can't it also arise in the universe? [Aristotle] |
| Full Idea: Movement can arise within a motionless animal out of the object itself, rather than being due to some external agent. But why should this not also be true of the universe? | |
| From: Aristotle (Physics [c.337 BCE], 252b24) | |
| A reaction: A nice objection to the Unmoved Mover concept of God. Unfortunately it is ruined by the modern realisation that an animal is never 'motionless', because brain activity is continuous, and ceases only with death. |
| 5116 | When there is unnatural movement (e.g. fire going downwards) the cause is obvious [Aristotle] |
| Full Idea: Examples of unnatural movements are something earthy moving upwards and fire moving downwards. …When they are moved unnaturally it is obvious what they are moved by, but this is not obvious in the case of their natural movements. | |
| From: Aristotle (Physics [c.337 BCE], 254b21) | |
| A reaction: Aristotle always struggles when he tries to give an account of 'unnatural' events. It is hard to see how it is unnatural when a wind blows a flame down, or volcanoes blow earth up. There is hardly a natural distinction of causes which are 'obvious'. |
| 399 | If the more you raise some earth the faster it moves, why does the whole earth not move? [Aristotle] |
| Full Idea: If you raise some earth and release it, it moves and won't stay put, and the more you raise it the faster it moves, so why does the whole earth not move? | |
| From: Aristotle (On the Heavens [c.336 BCE], 294a12) |
| 24045 | Movement is spatial, alteration, withering or growth [Aristotle] |
| Full Idea: There a four sorts of movement - spatial movement, alteration, withering and growth. | |
| From: Aristotle (De Anima [c.329 BCE], 406a12) | |
| A reaction: Large parts of Aristotle's writings attempt to explain these four. |
| 1738 | Practical reason is based on desire, so desire must be the ultimate producer of movement [Aristotle] |
| Full Idea: There seem to be two producers of movement, either desire or practical intellect, but practical reason begins in desire. | |
| From: Aristotle (De Anima [c.329 BCE], 433a16) |
| 24044 | Movement can be intrinsic (like a ship) or relative (like its sailors) [Aristotle] |
| Full Idea: It is not necessary for what moves things to be itself moving. For a thing can be moving in two ways - with reference to something else, or intrinsically. A ship is moving intrinsically, but sailors move because they are in something that is moving. | |
| From: Aristotle (De Anima [c.329 BCE], 406a03) | |
| A reaction: I love the way that Aristotle is desperate to explain the puzzle of movement, yet we just take it for granted. Very illuminating about puzzles. Newton's First Law of Motion. |
| 20063 | Motion fulfils potentiality [Aristotle] |
| Full Idea: Motion is the fulfilment of what exists potentially, in so far as it exists potentially. | |
| From: Aristotle (Physics [c.337 BCE], 201a10-11), quoted by Rowland Stout - Action 6 'Two' | |
| A reaction: We might put that as 'all motion is the fulfilment of a natural power'. But that gives the source of motion, and not its intrinsic nature. |
| 1739 | If all movement is either pushing or pulling, there must be a still point in between where it all starts [Aristotle] |
| Full Idea: Every movement being either a push or a pull, there must be a still point as with the circle, and this will be the point of departure for the movement. | |
| From: Aristotle (De Anima [c.329 BCE], 433b26) |
| 24064 | If something is pushed, it pushes back [Aristotle] |
| Full Idea: What has pushed something else makes the latter push as well. | |
| From: Aristotle (De Anima [c.329 BCE], 435b30) | |
| A reaction: Aristotle seems to have spotted that this is intrinsic to massive bodies, and is not just friction etc. Newton adds a vector to Aristotle's insight. |
| 1696 | Change goes from possession to loss (as in baldness), but not the other way round [Aristotle] |
| Full Idea: Change occurs from possession to privation, but from privation to possession is impossible; one who has gone blind does not recover sight nor does a bald man regain his hair nor does a toothless man grow new ones. | |
| From: Aristotle (Categories [c.331 BCE], 13a35) | |
| A reaction: Although this seems like an insight into entropy, it isn't an accurate observation, since trees lose their leaves, and then regain them in spring. Maybe somewhere men regrow their hair each spring. |
| 20918 | Void is a kind of place, so it can't explain place [Aristotle] |
| Full Idea: It is absurd to explain place by the void, as though this latter were not itself some kind of place. | |
| From: Aristotle (On the Heavens [c.336 BCE], 309b24) | |
| A reaction: Presumably this is aimed at Democritus. |
| 5099 | The universe as a whole is not anywhere [Aristotle] |
| Full Idea: The universe as a whole is not anywhere. | |
| From: Aristotle (Physics [c.337 BCE], 212b14) | |
| A reaction: This is what we pay philosophers for! Point out all the things which are staring us in the face, but we have never actually noticed. 'Everything that exists must have a location'? Can this truism really be false? |
| 5097 | If everything has a place, this causes an infinite regress, because each place must have place [Aristotle] |
| Full Idea: If place is an existing thing, then it will exist somewhere. For Zeno's puzzle needs explaining: if every existing thing is in place, an infinite regress occurs, because there will clearly have to be a place for place. | |
| From: Aristotle (Physics [c.337 BCE], 209a23) | |
| A reaction: This seems to be the basic dilemma with space. If it exists independently, it requires a location, but if it doesn't exist, how can anything have a location? Neither Newton, Leibniz nor Einstein seem to have solved the dilemma. |
| 5098 | Place is not shape, or matter, or extension between limits; it is the limits of a body [Aristotle] |
| Full Idea: Place must be one of four things: shape, or matter, or some kind of extension between the limits of the container, or the limits themselves. …The first three can evidently be ruled out…so it must be the limit of the containing body. | |
| From: Aristotle (Physics [c.337 BCE], 211b06) | |
| A reaction: As it stands this doesn't have much intuitive appeal. It is rather difficult to define a 'limit' without making some reference to 'space' and 'place'. One must read this chunk of Aristotle to see his drift. |
| 20920 | If there were many cosmoses, each would have its own time, giving many times [Aristotle] |
| Full Idea: If there were a plurality of heavens, in the same way the movement of each of them would be a time, so that many times would coexist. | |
| From: Aristotle (Physics [c.337 BCE], 218b3) | |
| A reaction: I take it that for Aristotle this is an absurdity, but for a modern cosmologist this is a real possibility. So which one is fastest? Can God rank them according to speed? |
| 13228 | There is no time without movement [Aristotle] |
| Full Idea: There can be no time without movement. | |
| From: Aristotle (Coming-to-be and Passing-away (Gen/Corr) [c.335 BCE], 337a24) | |
| A reaction: See Shoemaker's nice thought experiment as a challenge to this. Intuition seems to cry out that if movement stopped for a moment, that would not stop time, even though there was no way to measure its passing. |
| 5106 | Would there be time if there were no mind? [Aristotle] |
| Full Idea: It might be wondered whether or not there would be time if there were not mind. | |
| From: Aristotle (Physics [c.337 BCE], 223a21) | |
| A reaction: I like his caution. Some people leap to the conclusion that time is a product of mind. Personally (with my strongly realist tendencies) I don't believe it. |
| 22967 | It is unclear whether time depends on the existence of soul [Aristotle] |
| Full Idea: One might find it a difficult question, whether if there were no soul there would be time or not. | |
| From: Aristotle (Physics [c.337 BCE], 223a22) | |
| A reaction: If only we could arrange a meeting with Kant. Personally I take it to be simple - obviously time passed before minds emerged in the universe. Our whole modern account of reality realies on it. His problem is that only souls count things. |
| 22885 | For Aristotle time is not a process but a means for measuring processes [Aristotle, by Bardon] |
| Full Idea: For Aristotle time is not a process: It is a kind of 'number' or unit that can be used to describe processes in nature, analagous to the way ordinary numbers can be used to count things. | |
| From: report of Aristotle (Physics [c.337 BCE]) by Adrian Bardon - Brief History of the Philosophy of Time 1 'Aristotle's' | |
| A reaction: Bardon cites this when discussing Aristotle on Zeno's paradoxes. If the equivalent idea of length is that length is merely rulers for measuring it, this sounds like a bad idea. But if processes occur in time, how could time be a process? |
| 8590 | Time does not exist without change [Aristotle] |
| Full Idea: Time does not exist without change. | |
| From: Aristotle (Physics [c.337 BCE], 218b32) | |
| A reaction: His reasons are epistemological, and are nicely attacked by Shoemaker, in 'Time without Change'. There is something intuitively wrong about Aristotle's claim. If reality freezes, then 'how long was it frozen?' is a quite reasonable question. |
| 5104 | Time is an aspect of change [Aristotle] |
| Full Idea: Time is not change, but it is an aspect of change. | |
| From: Aristotle (Physics [c.337 BCE], 219a09) | |
| A reaction: I can't think of a better definition of time. Intuition says that time could continue when all change stopped (the 'frozen worlds' thought experiment), so that we can distinguish time from the change that gave rise to it (or the idea of it). |
| 22965 | Time measures rest, as well as change [Aristotle] |
| Full Idea: Since time is the measure of change, it will be measure of rest also. | |
| From: Aristotle (Physics [c.337 BCE], 221b07) | |
| A reaction: The thought seems to be that change leads us to a system of temporal measurement, which is then available fro measurement periods of rest. But totally eventless time would be a problem. Aristotle had no clocks. |
| 22959 | Time is not change, but the number we associate with change [Aristotle] |
| Full Idea: Time is a number of change in respect of the before and after. So time is not change but in the way in which change has a number. We discern the greater and the less by number, and greater and less change by time. Hence time is a kind of number. | |
| From: Aristotle (Physics [c.337 BCE], 219b01) | |
| A reaction: This is Aristotle's firmest assertion of the nature of time. It seems to be false to say that we need number in order to discern size (e.g. seeing who was given the biggest slice of cake). Surely we discern time before we measure it? |
| 22964 | Change only exists in time through its being temporally measure [Aristotle] |
| Full Idea: Time measures at once the change and the being of change, and this is what it is, for the change, to be in time, viz. its being's being measured. …This is what it is to be in time: their being's being measured by time. | |
| From: Aristotle (Physics [c.337 BCE], 221a05) | |
| A reaction: Among other things, this would presumably mean that animals are unaware of change, which seems unlikely. He may have a relaxed and intuitive (rather than precise) concept of 'measured'. |
| 1702 | Things may be necessary once they occur, but not be unconditionally necessary [Aristotle] |
| Full Idea: To say that everything that is, is of necessity, when it is, is not the same as saying unconditionally that it is of necessity. | |
| From: Aristotle (On Interpretation [c.330 BCE], 19a25) |
| 22956 | How can time exist, when it is composed of what has ceased to be and is yet to be? [Aristotle] |
| Full Idea: Some of time has been and is not, some of it is to be and is not yet. …But it would seem to be impossible that what is composed of things that are not should participate in being. | |
| From: Aristotle (Physics [c.337 BCE], 217b33) | |
| A reaction: This is his opening remark in the discussion of time, and he seems to be endorsing it, since he thinks of time as a form of measurement of change. |
| 5102 | If all of time has either ceased to exist, or has not yet happened, maybe time does not exist [Aristotle] |
| Full Idea: Some suspicion arises that time does not exist, since some of it has happened and does not exist, and some of it is in the future and does not yet exist. It appears impossible for anything that consists of things that do not exist to exist itself. | |
| From: Aristotle (Physics [c.337 BCE], 217b34) | |
| A reaction: This generates the popular paradox that Socrates cannot die, because no moment exists when his death could occur. It may be (as David Marshall has pointed out) that we do not experience the present, but only a vivid memory of the immediate past. |
| 5103 | Time is not change, but requires change in our minds to be noticed [Aristotle] |
| Full Idea: Time is not change … but time is not without change, for without any change (or any noticeable change) in our minds, time does not seem to pass. | |
| From: Aristotle (Physics [c.337 BCE], 218b19) | |
| A reaction: Aristotle has spotted what seems to be a key problem in understanding time, which is disentangling what occurs in nature from what occurs in our consciousness. The extreme views (naïve realism about time, or the view that it is imaginary) both seem wrong. |
| 22961 | The present moment is obviously a necessary feature of time [Aristotle] |
| Full Idea: It is manifest that if time were not, the now would not be either, and if the now were not, time would not be. | |
| From: Aristotle (Physics [c.337 BCE], 219b33) | |
| A reaction: I take this to be Aristotle's commitment to the A-series view, which needs a moving present moment. Despite Einstein and B-series eternalism, I remain in agreement with Aristotle. B-series fans struggle like theologians to explain 'now'. |
| 22916 | Unlike time, change goes at different rates, and is usually localised [Aristotle, by Le Poidevin] |
| Full Idea: Aristotle says time could not be the same thing as change, for first change can go at different rates, but not so time, and secondly change is confined to a part of space whereas time is universal. | |
| From: report of Aristotle (Physics [c.337 BCE], 218b11-) by Robin Le Poidevin - Travels in Four Dimensions 02 'As Change' | |
| A reaction: The observation that the speed of change varies seems to need a belief in uniform time. Le Poidevin doubts Aristotle's objections, because the theory concerns change in general, and not particular instances of it. |
| 617 | It is hard to see how either time or movement could come into existence or be destroyed [Aristotle] |
| Full Idea: It is impossible that movement should either come-to-be or be destroyed. The same can be said for time itself, since it is not even possible for there to be an earlier and a later if time does not exist. | |
| From: Aristotle (Metaphysics [c.324 BCE], 1071b06) |
| 16693 | Time has parts, but the now is not one of them, and time is not composed of nows [Aristotle] |
| Full Idea: Time has parts, some of which have been, others of which are going to be, but no part of it is. The now is not a part, because a part is a measure of the whole, which must be composed of parts. Time, however, does not seem to be composed of nows. | |
| From: Aristotle (Physics [c.337 BCE], 218a05), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 18.1 | |
| A reaction: As good an expression as you will ever find of the baffling nature of time. Only the past and the future seem substantial enough to exist. Only the now can be real, and yet it seems to be a nothing. In Phys IV.14 time is mind-dependent. |
| 22958 | Nows can't be linked together, any more than points on a line [Aristotle] |
| Full Idea: We take it that it is impossible for the nows to be adjoining one another, as it is for a point to be adjoining a point. | |
| From: Aristotle (Physics [c.337 BCE], 218a18) | |
| A reaction: This implies that instants are abstractions, rather than physical realities. Aristotle rejects atoms, so presumably sees prime matter as the underlying uniter of matter. Insistence on linking the smallest parts leads to modern physics. |
| 22963 | We measure change by time, and time by change, as they are interdefined [Aristotle] |
| Full Idea: Not only do we measure change by time, but time by change also, because they are defined by one another. | |
| From: Aristotle (Physics [c.337 BCE], 220b14) | |
| A reaction: He defends the idea that time is the 'number' of change, but this idea should sound a warning bell. He rejects the idea that time IS change. It is seems instrumentalist to make the existence of time depend on its measurement. |
| 22968 | Circular motion is the most obvious measure of time, and especially the celestial sphere [Aristotle] |
| Full Idea: Uniform circular motion is most of all a measure, because the number of this is most easily known. …This is why time is thought to be the motion of the [celestial] sphere, because the other changes are measured by this one. | |
| From: Aristotle (Physics [c.337 BCE], 223b14) | |
| A reaction: This makes the year the basic unit of time for the human race. Apparently minutes only became of interest when railway timetables appeared in the 1850s. |
| 22957 | We can't tell whether the changing present moment is one thing, or a succession of things [Aristotle] |
| Full Idea: It is not easy to see whether the now, which appears to be the boundary between past and future, remains always one and the same or is different from time to time. | |
| From: Aristotle (Physics [c.337 BCE], 218a08) | |
| A reaction: [also 219b13] Presumably the A-series view suggests that each present moment is different, but Broad's moving spotlight analogy gives the impression of a single present instant moving through time. If the present is one, what sort of thing is it? |
| 22966 | The present moment is a link (of past to future), and also a limit (of past and of future) [Aristotle] |
| Full Idea: The now is a link of time, for it links together past and future time, and is a limit of time, since it is a beginning of one and an end of the other. | |
| From: Aristotle (Physics [c.337 BCE], 222a10) | |
| A reaction: It is not clear how a limit (such as the boundary between two overlapping bits of paper) can also be a 'link'. He noticed the problem in Idea 22958. |
| 403 | The earth must be round and of limited size, because moving north or south makes different stars visible [Aristotle] |
| Full Idea: Clearly the earth is round and not of great size, because when we move north or south we find that very different stars are visible. | |
| From: Aristotle (On the Heavens [c.336 BCE], 297b30) |
| 402 | The Earth must be spherical, because it casts a convex shadow on the moon [Aristotle] |
| Full Idea: A lunar eclipse always has a convex dividing line, so, if it is eclipsed by the interposition of the earth, the circumference of the earth, being spherical, is responsible for the shape. | |
| From: Aristotle (On the Heavens [c.336 BCE], 297b29) |
| 5083 | Do things come to be from what is, or from what is not? Both seem problematical. [Aristotle] |
| Full Idea: Early thinkers made the mistake of claiming that nothing comes to be or ceases to be, on the grounds that for anything to come to be it would have to come either from what is or from what is not, but that neither of these is possible. | |
| From: Aristotle (Physics [c.337 BCE], 191a27) | |
| A reaction: Nothing in modern physics has (I think) solved this problem. On the one hand we have the conservation of energy, and on the other the Big Bang. Some talk of 'quantum fluctuations' triggering coming-to-be. Hm. |
| 16595 | If each thing can cease to be, why hasn't absolutely everything ceased to be long ago? [Aristotle] |
| Full Idea: If some one of the things 'which are' is constantly disappearing, why has not the whole of 'what is' been used up long ago and vanished away - assuming of course that the material of all the several comings-to-be was infinite? | |
| From: Aristotle (Coming-to-be and Passing-away (Gen/Corr) [c.335 BCE], 318a17) | |
| A reaction: This thought is the basis of Aquinas's Third Way for proving the existence of God (as the force which prevents the vicissitudes of nature from sliding into oblivion). |
| 619 | Something which both moves and is moved is intermediate, so it follows that there must be an unmoved mover [Aristotle] |
| Full Idea: Since that which is moved and which also moves is an intermediate, it follows that there must be something that moves without being moved. | |
| From: Aristotle (Metaphysics [c.324 BCE], 1072a19) |
| 613 | Even if the world is caused by fate, mind and nature are still prior causes [Aristotle] |
| Full Idea: Even if luck or the automatic are the cause of the world, mind and nature are prior causes still. | |
| From: Aristotle (Metaphysics [c.324 BCE], 1065b03) |
| 620 | The first mover is necessary, and because it is necessary it is good [Aristotle] |
| Full Idea: The existence of the first mover is necessary, and in that it is necessary it is good. | |
| From: Aristotle (Metaphysics [c.324 BCE], 1072b10) | |
| A reaction: This is the direct antithesis of David Hume's is/ought distinction (that the universe is value-free). |
| 1498 | Everyone agrees that the world had a beginning, but thinkers disagree over whether it will end [Aristotle] |
| Full Idea: All thinkers agree that the world had a beginning, but some claim that, having come into existence, it is everlasting. | |
| From: Aristotle (On the Heavens [c.336 BCE], 279b12) |
| 395 | It seems possible that there exists a limited number of other worlds apart from this one [Aristotle] |
| Full Idea: One might indeed be puzzled whether, just as the world about us exists, nothing prevents there being others as well, certainly more than one, though not an unlimited number | |
| From: Aristotle (On the Heavens [c.336 BCE], 274a26) |
| 24063 | What is born has growth, a prime, and a withering away [Aristotle] |
| Full Idea: What has been born must have growth, a prime of life, and a time of withering away. | |
| From: Aristotle (De Anima [c.329 BCE], 434a23) | |
| A reaction: Modern biologists don't seem much interested in the 'prime of life', but for Aristotle it is crucial, as the fulfilment of a thing's essential nature. Nietzsche would probably agree with Aristotle on this. We dread seeing one period of life as 'superior'. |
| 23302 | Plants have far less life than animals, but more life than other corporeal entities [Aristotle] |
| Full Idea: The genus of plants, whilst it is devoid of life compared with an animal, is endowed with life as compared with other corporeal entities. In the sea there are certain objects which one would be at a loss to determine whether they be animal or vegetable. | |
| From: Aristotle (The History of Animals [c.344 BCE], 588b09) | |
| A reaction: It seems that Aristotle takes life to come in degrees, assessed by the amount of physical vitality observed. This seems to make lambs more alive than sheep, which isn't very plausible. This is part of his 'gradualist' view of nature. |
| 23301 | There is a gradual proceeding from the inanimate to animals, with no clear borderlines [Aristotle] |
| Full Idea: Nature proceeds little by little from things lifeless to animal life so that it is impossible to determine the exact line of demarcation, nor on which side an intermediate form should lie. ...In plants there is a continuous ascent towards the animal. | |
| From: Aristotle (The History of Animals [c.344 BCE], 588b04) | |
| A reaction: This in itself should have alerted medieval Christians to the problematic nature of the idea that animal species were divinely created. |