<s id="id.1.2.3.05.07">For neither of these things would happen: for since, even on their own way of thinking, the rotation of the heavens takes place {1} around the center of the world, an added star or any other heavy weight added as well will neither help nor retard the motion; since such a weight, in such a circular motion, neither acquires nor loses nearness to or receding from the center, towards which it would be carried by reason of its heaviness. </s>
<s id="id.1.2.3.05.08">Hence they who say such things are deceived in the following way: because, in the first place, they decree that the force of the motive intelligence is in such a ratio to the resistance of the heavens, that it could itself move it with the swiftness at which it now does, and not at a greater one: but if, by the addition of some star, the resistance of the heavens is increased, then, they say, the motion of the heavens by the same motive force will be caused to be slower.</s>
<s id="id.1.2.3.05.09">Now they are led to believe this, in my opinion, because they see around us that someone who moves a large wheel, if a great weight is added on the other side, will then work more, or else the motion will become slower: but they do not note that the cause of such an effect is that the wheel is moved outside the center of the world; so that, when the added weight must be carried from the lowest point on the wheel to the highest, it is then moved contrary to nature, since it tends upward, receding from the center of the world. </s>
<s id="id.1.2.3.05.10">But if the wheel were rotating around the center of the world, who would ever say that it is hindered by the weight, since the weight in the circular motion does not come near nor does it recede from the center of the world?</s>
<s id="id.1.2.3.05.11">It is in a similar fashion that one must judge concerning the heavens. </s>
<s id="id.1.2.3.05.12"> For a star will be able to retard the motion only when it will be moved away from the place toward which it would naturally tend: but this never happens in a circular motion taking place around the center of the world, since it is never moved upward and never downward: hence the motion will not be retarded by the addition of a star. </s>
</p>
<p>
<s id="id.1.2.3.06.00"/>
<s id="id.1.2.3.06.01">As for the second [of the questions] asked above {1}, this is not the place to answer it; for one must first see by what things that are not moved naturally are moved. {2} </s>
</p>
<p>
<s id="id.1.2.3.07.00"/>
<s id="id.1.2.3.07.01">And similarly in the case of the circular motion that takes place outside the center of the world, a distinction must be made concerning the mobile, whether, that is, it is made of parts that are totally similar, or else different. </s>
<s id="id.1.2.3.07.02">And if the mobile is of totally similar parts, as, for example, a marble sphere, which is moved on an axis, this motion will be neither natural nor forced; since the center of heaviness of the sphere neither comes near nor recedes from the center of the world, and the heaviness of the parts of the sphere that go up is equal to that of the parts that go down, so that the sphere is always in equilibrium. </s>
<s id="id.1.2.3.07.03">And yet, by accident, such a circular motion is </s>
