display all the ideas for this combination of philosophers
10 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. |