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Single Idea 22747
[filed under theme 27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
]
Full Idea
If a ship moves forward and a man carries a rod backwards on it, then it is possible for an object to move without quitting its place.
Gist of Idea
A man walking backwards on a forwards-moving ship is moving in a fixed place
Source
Sextus Empiricus (Against the Physicists (two books) [c.180], II.056)
Book Ref
Sextus Empiricus: 'Against the Physicists/Against the Ethicists', ed/tr. Bury,R.G. [Harvard Loeb 1997], p.239
A Reaction
[summary of a verbose paragraph] The point is that you cannot define movement as change of place (contrary to Russell's proposal!). The concept of a place seems to be relative. Walking on a treadmill.
Related Idea
Idea 14168
Occupying a place and change are prior to motion, so motion is just occupying places at continuous times [Russell]
The
20 ideas
from 'Against the Physicists (two books)'
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22728
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Gods were invented as watchers of people's secret actions
[Sext.Empiricus]
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22730
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All men agree that God is blessed, imperishable, happy and good
[Sext.Empiricus]
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22731
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It is mad to think that what is useful to us, like lakes and rivers, are gods
[Sext.Empiricus]
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22732
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The perfections of God were extrapolations from mankind
[Sext.Empiricus]
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22734
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God is defended by agreement, order, absurdity of denying God, and refutations
[Sext.Empiricus]
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22735
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The original substance lacked motion or shape, and was given these by a cause
[Sext.Empiricus]
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22736
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God's sensations imply change, and hence perishing, which is absurd, so there is no such God
[Sext.Empiricus]
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22737
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An incorporeal God could do nothing, and a bodily god would perish, so there is no God
[Sext.Empiricus]
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22738
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The Divine must lack the virtues of continence and fortitude, because they are not needed
[Sext.Empiricus]
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22739
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God must suffer to understand suffering
[Sext.Empiricus]
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22740
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God without virtue is absurd, but God's virtues will be better than God
[Sext.Empiricus]
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22741
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The incorporeal is not in the nature of body, and so could not emerge from it
[Sext.Empiricus]
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22742
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Socrates either dies when he exists (before his death) or when he doesn't (after his death)
[Sext.Empiricus]
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22744
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Parts are not parts if their whole is nothing more than the parts
[Sext.Empiricus]
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22746
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If we try to conceive of a line with no breadth, it ceases to exist, and so has no length
[Sext.Empiricus]
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22747
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A man walking backwards on a forwards-moving ship is moving in a fixed place
[Sext.Empiricus]
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22748
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Some say motion is perceived by sense, but others say it is by intellect
[Sext.Empiricus]
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22749
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Time doesn't end with the Universe, because tensed statements about destruction remain true
[Sext.Empiricus]
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22750
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Time is divisible, into past, present and future
[Sext.Empiricus]
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22751
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If the present is just the limit of the past or the future, it can't exist because they don't exist
[Sext.Empiricus]
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