Book,  Paragraph

  1   I,  2 |         about the centre is circular motion, while the upward and downward
  2   I,  2 |      straight line, "upward" meaning motion away from the centre, and "
  3   I,  2 |           the centre, and "downward" motion towards it. All simple motion,
  4   I,  2 |        motion towards it. All simple motion, then, must be motion either
  5   I,  2 |         simple motion, then, must be motion either away from or towards
  6   I,  2 | composite-and in the latter case the motion will be that of the simple
  7   I,  2 |             brought to move with the motion of something else different
  8   I,  2 |             movement, being a simple motion, must be unnatural, if it
  9   I,  2 |           other element, its natural motion must be the contrary of
 10   I,  2 |             contrary of the circular motion. But a single thing has
 11   I,  2 |              and upward and downward motion are the contraries of one
 12   I,  2 |            moving with this circular motion which is unnatural to it
 13   I,  2 |             there will be some other motion which is natural to it.
 14   I,  2 |        cannot be. For if the natural motion is upward, it will be fire
 15   I,  2 |               Further, this circular motion is necessarily primary.
 16   I,  2 |              with a natural circular motion, as fire is ordained to
 17   I,  3 |           can it move with any other motion but its own, either itself
 18   I,  3 |             there can be no contrary motion to the circular, nature
 19   I,  3 |          which moves with a circular motion cannot admit of increase
 20   I,  3 |              greater than it is. The motion of a simple body must itself
 21   I,  3 |         latter being subdivided into motion away from and motion towards
 22   I,  3 |            into motion away from and motion towards the centre.~
 23   I,  4 |            there is no other form of motion opposed as contrary to the
 24   I,  4 |            is a contrary to circular motion, motion in a straight line
 25   I,  4 |         contrary to circular motion, motion in a straight line must
 26   I,  4 |             two forms of rectilinear motion are opposed to one another
 27   I,  4 |           meant is still rectilinear motion. For that is limited to
 28   I,  4 |           case is no better. For the motion is the same as that along
 29   I,  4 |         construct a circle and treat motion "along one semicircle as
 30   I,  4 |            semicircle as contrary to motion along the other. For example,
 31   I,  4 |            taking a complete circle, motion from E to F on the semicircle
 32   I,  4 |       semicircle G may be opposed to motion from F to E on the semicircle
 33   I,  4 |            contraries. Nor again can motion along the circle from A
 34   I,  4 |          regarded as the contrary of motion from A to C: for the motion
 35   I,  4 |          motion from A to C: for the motion goes from the same point
 36   I,  4 |             same point, and contrary motion was distinguished as motion
 37   I,  4 |          motion was distinguished as motion from a contrary to its contrary.
 38   I,  4 |            contrary. And even if the motion round a circle is the contrary
 39   I,  4 |              contrary of the reverse motion, one of the two would be
 40   I,  5 |       necessarily infinite: circular motion therefore is an impossibility.
 41   I,  5 |            which the one line in its motion cuts the other, is also
 42   I,  5 |             the time occupied by the motion of the infinite past the
 43   I,  5 |             there can be no circular motion of an infinite body.~(5)
 44   I,  6 |           bottom starts its downward motion, it cannot go farther than
 45   I,  6 |            the infinite performs the motion, a finite weight must necessarily
 46   I,  7 |          must always have its proper motion. Now if the infinite body
 47   I,  7 |              a place at which in its motion it can never by any possibility
 48   I,  7 |             possesses also a natural motion, that is to say, there is
 49   I,  7 |          time C, D will produce that motion in a patient less than B,
 50   I,  7 |             to F. E will produce the motion in BF in the time C. Thus
 51   I,  7 |           the force which causes its motion will have to be infinite.
 52   I,  7 |            which exhibits the latter motion. Again, what is it that
 53   I,  7 |             we assert, have the same motion. For a single clod moves
 54   I,  7 |            bodies no place for their motion; and without that movement
 55   I,  9 |             lie beyond the outermost motion; they continue through their
 56   I,  11|            to some, with contact and motion, since there is no process
 57   I,  11|        coming to be in contact or in motion. (b) It is used in another
 58  II,  1 |             which contains; and this motion, being perfect, contains
 59  II,  1 |            first body, whose natural motion is different, and imposed
 60  II,  1 |          already stated of the first motion is a possible one, it is
 61  II,  2 |            alike and all for ever in motion. We must think of the world
 62  II,  2 |            is length: for transverse motion is motion crossing motion
 63  II,  2 |             for transverse motion is motion crossing motion up and down.
 64  II,  2 |            motion is motion crossing motion up and down. Of the poles,
 65  II,  3 |                     3~Since circular motion is not the contrary of the
 66  II,  3 |              of the reverse circular motion, we must consider why there
 67  II,  3 |           why there is more than one motion, though we have to pursue
 68  II,  3 |             least one other circular motion: for a single movement of
 69  II,  4 |             same room.~Again, if the motion of the heaven is the measure
 70  II,  5 |              heaven and its circular motion are eternal. We must therefore
 71  II,  5 |          must therefore ask why this motion takes one direction and
 72  II,  6 |           two; and we expect natural motion to reach its maximum at
 73  II,  6 |       maximum at the goal, unnatural motion at the starting-point, and
 74  II,  6 |              then, further, that the motion cannot be irregular. For
 75  II,  7 |           set up in the air by their motion. Movement tends to create
 76  II,  7 |            heated by reason of their motion in air, which is turned
 77  II,  7 |            necessarily heated by its motion, and particularly in that
 78  II,  8 |             rest, or (2) both are in motion, or (3) the one is at rest
 79  II,  8 |             at rest and the other in motion.~(1) That both should be
 80  II,  8 |              first, that both are in motion, we have the absurdity that
 81  II,  8 |              either that both are in motion or that the star alone moves,
 82  II,  8 |             moving with their proper motion, the larger moves quicker.
 83  II,  8 |      swiftest and most selfcontained motion, for forward movement it
 84  II,  9 |            thinkers suppose that the motion of bodies of that size must
 85  II,  9 |               since on our earth the motion of bodies far inferior in
 86  II,  9 |           are moving with so rapid a motion, how should they not produce
 87  II,  9 |            Pythagoreans say that the motion of the stars produces a
 88  II,  9 |              which are themselves in motion, produce noise and friction:
 89  II,  9 |           that on a large vessel the motion of mast and poop should
 90  II,  9 |            every one supposes, their motion would necessarily cause
 91  II,  9 |            of them can move with the motion either of animate nature
 92  II,  10|              circle with the reverse motion to that of the heavens.
 93  II,  12|            distance from the primary motion. For we should expect, since
 94  II,  12|           the primary body shows one motion only, that the body which
 95  II,  12|           Why is it that the primary motion includes such a multitude
 96  II,  12|            more attached to the same motion?~On these questions, I say,
 97  II,  12|            that into the one primary motion is crowded a vast multitude
 98  II,  12|    reasonable. For this single first motion has to move many of the
 99  II,  12|          order, giving to the single motion many bodies and to the single
100  II,  12|           has its particular natural motion, to which the general movement
101  II,  12|           which move with a circular motion, in respect of substance
102  II,  13|          whether it is at rest or in motion, and of its shape.~I. As
103  II,  13|              and day by its circular motion about the centre. They further
104  II,  13|      advanced concerning its rest or motion are similar. For here too
105  II,  13|             is "rolled", and thus in motion, about the axis of the whole
106  II,  13|             be the sole principle of motion or of rest. If, then, it
107  II,  13|            with Empedocles, that the motion of the heavens, moving about
108  II,  13|              cup is given a circular motion, though it is often underneath
109  II,  13|         cease to prevent the earth’s motion, where will the earth move
110  II,  13|               but there must be some motion which is natural to it.
111  II,  13|              it. Will this be upward motion or downward or what? It
112  II,  13|              what? It must have some motion; and if upward and downward
113  II,  13|           and if upward and downward motion are alike to it, and the
114  II,  13|         because of its indifference. Motion upward and downward and
115  II,  13|            still but not about their motion,-why, I mean, one thing,
116  II,  14|             it to be "rolled" and in motion about the pole as axis.
117  II,  14|            the fact that the earth’s motion, whether the earth be at
118  II,  14|          must needs be a constrained motion. It cannot be the movement
119  II,  14|              move with more than one motion. The earth, then, also,
120  II,  14|              that the reason of this motion is that a thing which possesses
121  II,  14|          impulse. Therefore earth in motion, whether in a mass or in
122 III,  2 |            is natural to it, clearly motion to this place is natural
123 III,  2 |   constrained, what is hindering its motion? Something, which is at
124 III,  2 |          explain the manner of their motion and the kind of movement
125 III,  2 |           the prime mover must cause motion not by constraint but naturally.
126 III,  2 |           the prime mover must cause motion in virtue of its own natural
127 III,  2 |              must move with a single motion, and therefore not without
128 III,  2 |           before they try to produce motion and separation. But there
129 III,  2 |            Again, a body which is in motion but has neither weight nor
130 III,  2 |         impossible. Hence, since the motion of the weightless body will
131 III,  2 |            qua light produces upward motion, being propelled and set
132 III,  2 |           being propelled and set in motion by the force, and qua heavy
133 III,  2 |            heavy produces a downward motion. In either case the force
134 III,  5 |              one movement. With this motion the greater their quantity
135 III,  5 |         moves faster with the upward motion which belongs to it. But
136  IV,  3 |          thought that produces local motion and that which is so moved
137  IV,  3 |             body to its own place is motion towards its own form. (It
138  IV,  3 |              are moved with the same motion this result is necessarily
139  IV,  3 |        liable to disease whether the motion is towards health or towards
140  IV,  3 |           towards its own place. For motion is equally immediate in
141  IV,  3 |               and the meaning of the motion of a body to its own place,
142  IV,  4 |             centre towards which the motion of heavy things, and away
143  IV,  5 |              upward and the downward motion. Hence air and water each
144  IV,  5 |             downward, and the second motion will be abolished. And so,
145  IV,  6 |         responsible for the downward motion of the heavy body and the