Book IX Chapter 5

As all potencies¹ are either innate², like the senses, or come by practice, like the power of playing the flute³, or by learning, like artistic⁴ power, those which come by practice or by rational formula we must acquire by previous exercise but this is not necessary with those which are not of this nature and which imply passivity.

Since that which is ‘capable’ is capable of something and at some time in some way (with all the other qualifications which must be present in the definition), and since some things can produce change according to a rational formula and their potencies involve such a formula, while other things are nonrational and their potencies are non-rational, and the former potencies must be in a living thing, while the latter can be both in the living and in the lifeless; as regards potencies of the latter kind, when the agent and the patient meet in the way appropriate to the potency⁵ in question, the one must act and the other be acted on, but with the former kind of potency this is not necessary. For the nonrational potencies are all productive of one effect each, but the rational produce contrary effects, so that if they produced their effects necessarily they would produce contrary effects at the same time; but this is impossible. There must, then, be something else that decides; I mean by this, desire or will. For whichever of two things the animal desires decisively, it will do, when it is present, and meets the passive object, in the way appropriate to the potency in question. Therefore everything which has a rational potency, when it desires that for which it has a potency and in the circumstances in which it has the potency, must do this. And it has the potency in question when the passive object is present and is in a certain state; if not it will not be able to act. (To add the qualification ‘if nothing external prevents it’ is not further necessary; for it has the potency on the terms on which this is a potency of acting⁶, and it is this not in all circumstances but on certain conditions, among which will be the exclusion⁷ of external hindrances⁸; for these are barred by some of the positive qualifications.) And so even if one has a rational wish, or an appetite, to do two things or contrary things at the same time, one will not do them; for it is not on these terms that one has the potency for them, nor is it a potency of doing both at the same time, since one will do the things which it is a potency of doing, on the terms on which one has the potency.

1 potencies   

n.威力( potency的名词复数 )；权力；效力；（男人的）性交能力

参考例句：

• The soft gelatin liquid filled capsule manufacturing process is the same for all proposed potencies. 软明胶液体填注胶囊的生产工艺对所有提出的效用是一样的。 来自互联网

2 innate   

adj.天生的，固有的，天赋的

参考例句：

• You obviously have an innate talent for music.你显然有天生的音乐才能。
• Correct ideas are not innate in the mind.人的正确思想不是自己头脑中固有的。

3 flute   

n.长笛；v.吹笛

参考例句：

• He took out his flute, and blew at it.他拿出笛子吹了起来。
• There is an extensive repertoire of music written for the flute.有很多供长笛演奏的曲目。

4 artistic   

adj.艺术(家)的，美术(家)的；善于艺术创作的

参考例句：

• The picture on this screen is a good artistic work.这屏风上的画是件很好的艺术品。
• These artistic handicrafts are very popular with foreign friends.外国朋友很喜欢这些美术工艺品。

5 potency   

n. 效力，潜能

参考例句：

• Alcohol increases the drug's potency.酒精能增加这种毒品的效力。
• Sunscreen can lose its potency if left over winter in the bathroom cabinet.如果把防晒霜在盥洗室的壁橱里放一个冬天，就有可能失效。

6 acting   

n.演戏，行为，假装；adj.代理的，临时的，演出用的

参考例句：

• Ignore her,she's just acting.别理她，她只是假装的。
• During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。

7 exclusion   

n.拒绝，排除，排斥，远足，远途旅行

参考例句：

• Don't revise a few topics to the exclusion of all others.不要修改少数论题以致排除所有其他的。
• He plays golf to the exclusion of all other sports.他专打高尔夫球，其他运动一概不参加。

8 hindrances   

阻碍者( hindrance的名词复数 )； 障碍物； 受到妨碍的状态

参考例句：

• She also speaks out against the traditional hindrances to freedom. 她甚至大声疾呼，反对那些阻挡自由的、统礼教的绊脚石。
• When this stage is reached then the hindrances and karma are overcome. 唯此状态达到后，则超越阻碍和因果。