Chapter 3

Since circular motion is not the contrary of the reverse circular motion, we must consider why there is more than one motion, though we have to pursue our inquiries¹ at a distance-a distance created not so much by our spatial² position as by the fact that our senses enable us to perceive very few of the attributes of the heavenly bodies. But let not that deter³ us. The reason must be sought in the following facts. Everything which has a function exists for its function. The activity of God is immortality⁴, i.e. eternal life. Therefore the movement of that which is divine must be eternal. But such is the heaven, viz. a divine body, and for that reason to it is given the circular body whose nature it is to move always in a circle. Why, then, is not the whole body of the heaven of the same character as that part? Because there must be something at rest at the centre of the revolving⁵ body; and of that body no part can be at rest, either elsewhere or at the centre. It could do so only if the body’s natural movement were towards the centre. But the circular movement is natural, since otherwise it could not be eternal: for nothing unnatural⁶ is eternal. The unnatural is subsequent to the natural, being a derangement⁷ of the natural which occurs in the course of its generation. Earth then has to exist; for it is earth which is at rest at the centre. (At present we may take this for granted: it shall be explained later.) But if earth must exist, so must fire. For, if one of a pair of contraries naturally exists, the other, if it is really contrary, exists also naturally. In some form it must be present, since the matter of contraries is the same. Also, the positive is prior to its privation (warm, for instance, to cold), and rest and heaviness stand for the privation of lightness and movement. But further, if fire and earth exist, the intermediate bodies must exist also: each element stands in a contrary relation to every other. (This, again, we will here take for granted and try later to explain.) these four elements generation clearly is involved, since none of them can be eternal: for contraries interact with one another and destroy one another. Further, it is inconceivable that a movable body should be eternal, if its movement cannot be regarded as naturally eternal: and these bodies we know to possess movement. Thus we see that generation is necessarily involved. But if so, there must be at least one other circular motion: for a single movement of the whole heaven would necessitate⁸ an identical relation of the elements of bodies to one another. This matter also shall be cleared up in what follows: but for the present so much is clear, that the reason why there is more than one circular body is the necessity of generation, which follows on the presence of fire, which, with that of the other bodies, follows on that of earth; and earth is required because eternal movement in one body necessitates⁹ eternal rest in another.

1 inquiries   

n.调查( inquiry的名词复数 )；疑问；探究；打听

参考例句：

• He was released on bail pending further inquiries. 他获得保释，等候进一步调查。
• I have failed to reach them by postal inquiries. 我未能通过邮政查询与他们取得联系。 来自《现代汉英综合大词典》

2 spatial   

adj.空间的，占据空间的

参考例句：

• This part of brain judges the spatial relationship between objects.大脑的这部分判断物体间的空间关系。
• They said that time is the feeling of spatial displacement.他们说时间是空间位移的感觉。

3 deter   

vt.阻止，使不敢，吓住

参考例句：

• Failure did not deter us from trying it again.失败并没有能阻挡我们再次进行试验。
• Dogs can deter unwelcome intruders.狗能够阻拦不受欢迎的闯入者。

4 immortality   

n.不死，不朽

参考例句：

• belief in the immortality of the soul 灵魂不灭的信念
• It was like having immortality while you were still alive. 仿佛是当你仍然活着的时候就得到了永生。

5 revolving   

adj.旋转的，轮转式的；循环的v.（使）旋转( revolve的现在分词 )；细想

参考例句：

• The theatre has a revolving stage. 剧院有一个旋转舞台。
• The company became a revolving-door workplace. 这家公司成了工作的中转站。

6 unnatural   

adj.不自然的；反常的

参考例句：

• Did her behaviour seem unnatural in any way?她有任何反常表现吗？
• She has an unnatural smile on her face.她脸上挂着做作的微笑。

7 derangement   

n.精神错乱

参考例句：

• She began to think he was in mental derangement. 她开始想这个人一定是精神错乱了。
• Such a permutation is called a derangement. 这样的一个排列称为错位排列。

8 necessitate   

v.使成为必要，需要

参考例句：

• Your proposal would necessitate changing our plans.你的提议可能使我们的计划必须变更。
• The conversion will necessitate the complete rebuilding of the interior.转变就必需完善内部重建。

9 necessitates   

使…成为必要，需要( necessitate的第三人称单数 )

参考例句：

• The increase in population necessitates a greater food supply. 人口的增加需要更多食物供应。
• Your proposal necessitates borrowing money. 你的提议使借款成为必要。