Book XI Chapter 6

The saying of Protagoras is like the views we have mentioned; he said that man is the measure of all things, meaning simply that that which seems to each man also assuredly is. If this is so, it follows that the same thing both is and is not, and is bad and good, and that the contents of all other opposite statements are true, because often a particular thing appears beautiful to some and the contrary of beautiful to others, and that which appears to each man is the measure. This difficulty may be solved by considering the source of this opinion. It seems to have arisen in some cases from the doctrine² of the natural philosophers, and in others from the fact that all men have not the same views about the same things, but a particular thing appears pleasant to some and the contrary of pleasant to others.

That nothing comes to be out of that which is not, but everything out of that which is, is a dogma common to nearly all the natural philosophers. Since, then, white cannot come to be if the perfectly³ white and in no respect not-white existed before, that which becomes white must come from that which is not white; so that it must come to be out of that which is not (so they argue), unless the same thing was at the beginning white and not-white. But it is not hard to solve this difficulty; for we have said in our works on physics in what sense things that come to be come to be from that which is not, and in what sense from that which is.

But to attend equally to the opinions and the fancies of disputing parties is childish; for clearly one of them must be mistaken. And this is evident from what happens in respect of sensation; for the same thing never appears sweet to some and the contrary of sweet to others, unless in the one case the sense-organ which discriminates⁴ the aforesaid flavours has been perverted⁵ and injured. And if this is so the one party must be taken to be the measure, and the other must not. And say the same of good and bad, and beautiful and ugly, and all other such qualities. For to maintain the view we are opposing is just like maintaining that the things that appear to people who put their finger under their eye and make the object appear two instead of one must be two (because they appear to be of that number) and again one (for to those who do not interfere⁶ with their eye the one object appears one).

In general, it is absurd to make the fact that the things of this earth are observed to change and never to remain in the same state, the basis of our judgement about the truth. For in pursuing the truth one must start from the things that are always in the same state and suffer no change. Such are the heavenly bodies; for these do not appear to be now of one nature and again of another, but are manifestly always the same and share in no change.

Further, if there is movement, there is also something moved, and everything is moved out of something and into something; it follows that that that which is moved must first be in that out of which it is to be moved, and then not be in it, and move into the other and come to be in it, and that the contradictory⁷ statements are not true at the same time, as these thinkers assert they are.

And if the things of this earth continuously flow and move in respect of quantity-if one were to suppose this, although it is not true-why should they not endure in respect of quality? For the assertion of contradictory statements about the same thing seems to have arisen largely from the belief that the quantity of bodies does not endure, which, our opponents hold, justifies⁸ them in saying that the same thing both is and is not four cubits long. But essence depends on quality, and this is of determinate nature, though quantity is of indeterminate.

Further, when the doctor orders people to take some particular food, why do they take it? In what respect is ‘this is bread’ truer than ‘this is not bread’? And so it would make no difference whether one ate or not. But as a matter of fact they take the food which is ordered, assuming that they know the truth about it and that it is bread. Yet they should not, if there were no fixed⁹ constant nature in sensible things, but all natures moved and flowed for ever.

Again, if we are always changing and never remain the same, what wonder is it if to us, as to the sick, things never appear the same? (For to them also, because they are not in the same condition as when they were well, sensible qualities do not appear alike; yet, for all that, the sensible things themselves need not share in any change, though they produce different, and not identical, sensations in the sick. And the same must surely happen to the healthy if the afore-said change takes place.) But if we do not change but remain the same, there will be something that endures.

As for those to whom the difficulties mentioned are suggested by reasoning, it is not easy to solve the difficulties to their satisfaction, unless they will posit¹ something and no longer demand a reason for it; for it is only thus that all reasoning and all proof is accomplished¹⁰; if they posit nothing, they destroy discussion and all reasoning. Therefore with such men there is no reasoning. But as for those who are perplexed¹¹ by the traditional difficulties, it is easy to meet them and to dissipate the causes of their perplexity. This is evident from what has been said.

It is manifest, therefore, from these arguments that contradictory statements cannot be truly made about the same subject at one time, nor can contrary statements, because every contrariety depends on privation. This is evident if we reduce the definitions of contraries to their principle.

Similarly, no intermediate between contraries can be predicated of one and the same subject, of which one of the contraries is predicated. If the subject is white we shall be wrong in saying it is neither black nor white, for then it follows that it is and is not white; for the second of the two terms we have put together is true of it, and this is the contradictory of white.

We could not be right, then, in accepting the views either of Heraclitus or of Anaxagoras. If we were, it would follow that contraries would be predicated of the same subject; for when Anaxagoras says that in everything there is a part of everything, he says nothing is sweet any more than it is bitter, and so with any other pair of contraries, since in everything everything is present not potentially only, but actually and separately. And similarly all statements cannot be false nor all true, both because of many other difficulties which might be adduced as arising from this position, and because if all are false it will not be true to say even this, and if all are true it will not be false to say all are false.

1 posit   

v.假定，认为

参考例句：

• If she needs salvation,she will posit a savior.如果她需要救助，她就会设想一个救助者。
• Other historians posit that she died of old age around 550 BC.别的史学家则认为她一直活到公元前550年左右才寿终正寝。

2 doctrine   

n.教义；主义；学说

参考例句：

• He was impelled to proclaim his doctrine.他不得不宣扬他的教义。
• The council met to consider changes to doctrine.宗教议会开会考虑更改教义。

3 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

4 discriminates   

分别，辨别，区分( discriminate的第三人称单数 )； 歧视，有差别地对待

参考例句：

• The new law discriminates against lower-paid workers. 这条新法律歧视低工资的工人。
• One test governs state legislation that discriminates against interstate commerce. 一个检验约束歧视州际商业的州立法。 来自英汉非文学 - 环境法 - 环境法

5 perverted   

adj.不正当的v.滥用( pervert的过去式和过去分词 )；腐蚀；败坏；使堕落

参考例句：

• Some scientific discoveries have been perverted to create weapons of destruction. 某些科学发明被滥用来生产毁灭性武器。
• sexual acts, normal and perverted 正常的和变态的性行为

6 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

7 contradictory   

adj.反驳的，反对的，抗辩的；n.正反对，矛盾对立

参考例句：

• The argument is internally contradictory.论据本身自相矛盾。
• What he said was self-contradictory.他讲话前后不符。

8 justifies   

证明…有理( justify的第三人称单数 )； 为…辩护； 对…作出解释； 为…辩解（或辩护）

参考例句：

• Their frequency of use both justifies and requires the memorization. 频繁的使用需要记忆，也促进了记忆。 来自About Face 3交互设计精髓
• In my judgement the present end justifies the means. 照我的意见，只要目的正当，手段是可以不计较的。

9 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

10 accomplished   

adj.有才艺的；有造诣的；达到了的

参考例句：

• Thanks to your help,we accomplished the task ahead of schedule.亏得你们帮忙,我们才提前完成了任务。
• Removal of excess heat is accomplished by means of a radiator.通过散热器完成多余热量的排出。

11 perplexed   

adj.不知所措的

参考例句：

• The farmer felt the cow,went away,returned,sorely perplexed,always afraid of being cheated.那农民摸摸那头牛，走了又回来，犹豫不决，总怕上当受骗。
• The child was perplexed by the intricate plot of the story.这孩子被那头绪纷繁的故事弄得迷惑不解。