On Liberty, Chapter II: Of the Liberty of Thought and Discussion (from)

When we consider either the history of opinion, or the ordinary conduct of human life, to what is it to be ascribed that the one and the other are no worse than they are? Not certainly to the inherent force of the human understanding; for, on any matter not self-evident, there are ninety-nine persons totally incapable of judging of it, for one who is capable; and the capacity of the hundredth person is only comparative; for the majority of the eminent men of every past generation held many opinions now known to be erroneous, and did or approved numerous things which no one will now justify. Why is it, then, that there is on the whole a preponderance among mankind of rational opinions and rational conduct? If there really is this preponderance—which there must be, unless human affairs are, and have always been, in an almost desperate state—it is owing to a quality of the human mind, the source of everything respectable in man either as an intellectual or as a moral being, namely, that his errors are corrigible. He is capable of rectifying his mistakes, by discussion and experience. Not by experience alone. There must be discussion, to show how experience is to be interpreted. Wrong opinions and practices gradually yield to fact and argument: but facts and arguments, to produce any effect on the mind, must be brought before it. Very few facts are able to tell their own story, without comments to bring out their meaning. The whole strength and value, then, of human judgment, depending on the one property, that it can be set right when it is wrong, reliance can be placed on it only when the means of setting it right are kept constantly at hand. In the case of any person whose judgment is really deserving of confidence, how has it become so? Because he has kept his mind open to criticism of his opinions and conduct. Because it has been his practice to listen to all that could be said against him; to profit by as much of it as was just, and expound to himself, and upon occasion to others, the fallacy of what was fallacious. Because he has felt, that the only way in which a human being can make some approach to knowing the whole of a subject, is by hearing what can be said about it by persons of every variety of opinion, and studying all modes in which it can be looked at by every character of mind. No wise man ever acquired his wisdom in any mode but this; nor is it in the nature of human intellect to become wise in any other manner. The steady habit of correcting and completing his own opinion by collating it with those of others, so far from causing doubt and hesitation in carrying it into practice, is the only stable foundation for a just reliance on it: for, being cognisant of all that can, at least obviously, be said against him, and having taken up his position against all gainsayers—knowing that he has sought for objections and difficulties, instead of avoiding them, and has shut out no light which can be thrown upon the subject from any quarter—he has a right to think his judgment better than that of any person, or any multitude, who have not gone through a similar process.

当我们考察意见的历史，或者考察人类生活的日常行为时，人类的意见和行为之所以不比现在更糟，应该归功于什么呢？当然不是归功于人类理解力本身的力量；因为在任何并非不证自明的事情上，有九十九个人完全没有能力判断，才有一个人有这个能力；而这第一百个人的能力也只是相对而言的；因为过去每一代杰出人物中的大多数，都持有许多现在已知是错误的意见，做过或赞成过许多现在没有人会为之辩护的事情。那么，为什么从总体上看，人类之中合理的意见和合理的行为还是占着优势呢？如果确实存在这种优势——而它必定存在，除非人类的事务现在是、而且一向是处在几乎绝望的境地——那就要归功于人类心灵的一种品质，这种品质是人身上一切可敬之处的源泉，无论作为一个理智的存在者还是作为一个道德的存在者都是如此，这就是：他的错误是可以纠正的。他能够通过讨论和经验来改正自己的错误。不能只靠经验。必须有讨论，来说明怎样解释经验。错误的意见和做法会逐渐让位于事实和论证：但是事实和论证要对心灵产生任何作用，必须被摆到心灵面前。很少有事实能够自己讲出自己的故事，而不需要评论来揭示它们的意义。那么，人类判断的全部力量和价值，既然依赖于这样一个特性，即它在错误时能够被纠正，那么，只有当纠正它的手段一直放在手边的时候，它才是可以信赖的。在任何一个其判断真正值得信任的人身上，这种判断是怎样变得值得信任的呢？是因为他一直向别人对他的意见和行为的批评敞开心胸。是因为他一向惯于倾听一切可以用来反对他的话；从中吸取一切公正的部分，并且向自己、必要时也向别人说明那些谬误之处为什么是谬误的。是因为他感觉到，一个人要接近于了解一个问题的全部，唯一的途径就是听取持有各种不同意见的人对它的说法，研究各种不同性格的头脑看待它的一切方式。没有一个有智慧的人是用别的方式获得他的智慧的；人类理智的本性，也不可能以任何其他方式变得有智慧。把自己的意见同别人的意见加以对照，从而不断地纠正它、完善它，这种牢固的习惯，远不会在付诸实践时造成怀疑和犹豫，反而是使人可以正当地信赖自己意见的唯一稳固的基础：因为，他已经了解了一切可以反对他的话，至少是一切显而易见的反对意见，并且已经针对一切反对者确立了自己的立场——他知道自己是寻求反对意见和困难，而不是回避它们，没有把来自任何方面、可能照亮这个问题的光挡在外面——所以，他有权认为自己的判断胜过任何没有经过类似过程的个人或群众的判断。

Let us now pass to the second division of the argument, and dismissing the supposition that any of the received opinions may be false, let us assume them to be true, and examine into the worth of the manner in which they are likely to be held, when their truth is not freely and openly canvassed. However unwillingly a person who has a strong opinion may admit the possibility that his opinion may be false, he ought to be moved by the consideration that however true it may be, if it is not fully, frequently, and fearlessly discussed, it will be held as a dead dogma, not a living truth.

现在让我们转入论证的第二部分。我们撇开“任何公认的意见可能是错误的”这个假设，而假定它们都是真的，来考察：当它们的真理性不被自由、公开地讨论时，人们持有它们的方式有什么价值。一个持有强烈意见的人，无论多么不情愿承认自己的意见可能是错的，也应该被这样一个考虑所打动：无论它多么正确，如果不经常地、充分地、无畏地加以讨论，它就会作为一种僵死的教条，而不是一种活生生的真理被人持有。

If the intellect and judgment of mankind ought to be cultivated, a thing which Protestants at least do not deny, on what can these faculties be more appropriately exercised by any one, than on the things which concern him so much that it is considered necessary for him to hold opinions on them? If the cultivation of the understanding consists in one thing more than in another, it is surely in learning the grounds of one's own opinions. Whatever people believe, on subjects on which it is of the first importance to believe rightly, they ought to be able to defend against at least the common objections. But, some one may say, "Let them be taught the grounds of their opinions. It does not follow that opinions must be merely parroted because they are never heard controverted. Persons who learn geometry do not simply commit the theorems to memory, but understand and learn likewise the demonstrations; and it would be absurd to say that they remain ignorant of the grounds of geometrical truths, because they never hear any one deny, and attempt to disprove them." Undoubtedly: and such teaching suffices on a subject like mathematics, where there is nothing at all to be said on the wrong side of the question. The peculiarity of the evidence of mathematical truths is, that all the argument is on one side. There are no objections, and no answers to objections. But on every subject on which difference of opinion is possible, the truth depends on a balance to be struck between two sets of conflicting reasons. Even in natural philosophy, there is always some other explanation possible of the same facts; some geocentric theory instead of heliocentric, some phlogiston instead of oxygen; and it has to be shown why that other theory cannot be the true one: and until this is shown, and until we know how it is shown, we do not understand the grounds of our opinion. But when we turn to subjects infinitely more complicated, to morals, religion, politics, social relations, and the business of life, three-fourths of the arguments for every disputed opinion consist in dispelling the appearances which favour some opinion different from it. The greatest orator, save one, of antiquity, has left it on record that he always studied his adversary's case with as great, if not with still greater, intensity than even his own. What Cicero practised as the means of forensic success, requires to be imitated by all who study any subject in order to arrive at the truth. He who knows only his own side of the case, knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side; if he does not so much as know what they are, he has no ground for preferring either opinion. The rational position for him would be suspension of judgment, and unless he contents himself with that, he is either led by authority, or adopts, like the generality of the world, the side to which he feels most inclination. Nor is it enough that he should hear the arguments of adversaries from his own teachers, presented as they state them, and accompanied by what they offer as refutations. That is not the way to do justice to the arguments, or bring them into real contact with his own mind. He must be able to hear them from persons who actually believe them; who defend them in earnest, and do their very utmost for them. He must know them in their most plausible and persuasive form; he must feel the whole force of the difficulty which the true view of the subject has to encounter and dispose of; else he will never really possess himself of the portion of truth which meets and removes that difficulty. Ninety-nine in a hundred of what are called educated men are in this condition; even of those who can argue fluently for their opinions. Their conclusion may be true, but it might be false for anything they know: they have never thrown themselves into the mental position of those who think differently from them, and considered what such persons may have to say; and consequently they do not, in any proper sense of the word, know the doctrine which they themselves profess. They do not know those parts of it which explain and justify the remainder; the considerations which show that a fact which seemingly conflicts with another is reconcilable with it, or that, of two apparently strong reasons, one and not the other ought to be preferred. All that part of the truth which turns the scale, and decides the judgment of a completely informed mind, they are strangers to; nor is it ever really known, but to those who have attended equally and impartially to both sides, and endeavoured to see the reasons of both in the strongest light. So essential is this discipline to a real understanding of moral and human subjects, that if opponents of all important truths do not exist, it is indispensable to imagine them, and supply them with the strongest arguments which the most skilful devil's advocate can conjure up.

如果人类的理智和判断力应该得到培养——这一点至少新教徒是不否认的——那么，还有什么事情比一个人最关切、因而被认为必须对之持有意见的那些事情，更适于让他运用这些官能呢？如果说理解力的培养主要在于某一件事，那必定就是了解自己意见的根据。在那些最需要正确信仰的问题上，人们无论相信什么，都应该至少能够针对常见的反对意见为它辩护。可是，有人会说：“那就把他们意见的根据教给他们好了。并不能因为他们从来没有听到过别人的反驳，就说他们的意见一定只是鹦鹉学舌。学几何的人并不只是把定理背下来，而是同时理解并学会了证明；如果因为他们从来没听见有人否认和试图推翻几何真理，就说他们不了解几何真理的根据，那就荒谬了。”毫无疑问：像数学这样的学科，错误的一方根本无话可说，这样的教学是足够的。数学真理的证据的特殊之处在于，所有的论证都在一边。没有反对意见，也没有对反对意见的回答。但是，在一切可能存在意见分歧的问题上，真理都取决于在两组相互冲突的理由之间求得一种平衡。即使在自然哲学中，对同样的事实也总有可能作出另外的解释；有地心说来代替日心说，有燃素说来代替氧气说；必须说明为什么那另一种理论不可能是正确的：在这一点得到说明之前，在我们知道它是怎样被说明的之前，我们就不了解我们意见的根据。而当我们转向那些无比复杂的问题，转向道德、宗教、政治、社会关系和生活事务时，为每一种有争议的意见所作的论证，有四分之三都在于驱散那些有利于与之不同的意见的表面现象。古代最伟大的演说家中，除了一人之外，有一位曾经记载说，他总是以同样大的、甚至更大的专注去研究对手的论点，而不只是研究自己的论点。西塞罗作为在法庭上取胜的手段而实行的做法，凡是为了达到真理而研究任何问题的人，都必须效法。一个只知道自己一方观点的人，对这一方也知之甚少。他的理由也许是好的，也许没有人能驳倒它们。但是，如果他同样不能驳倒对方的理由，如果他甚至连对方的理由是什么都不知道，那么他就没有根据偏爱这两种意见中的任何一种。对他来说，合理的立场是暂停判断；除非他满足于此，否则他不是被权威牵着走，就是像世上大多数人那样，采取自己最倾向的一方。他从自己的老师那里，听老师转述对手的论点，并附上老师们提供的所谓驳斥，这也是不够的。那不是公正对待这些论点的方式，也不能让它们和他自己的头脑真正接触。他必须能从那些真正相信这些论点、认真为之辩护、竭尽全力维护它们的人那里听到它们。他必须了解它们最有道理、最有说服力的形式；他必须感受到真正的观点所必须面对和解决的那个困难的全部分量；否则，他永远也不会真正掌握真理中能够面对并消除这个困难的那一部分。在所谓受过教育的人中间，一百个人里有九十九个都处在这种境地；甚至那些能为自己的意见流畅地辩论的人也是如此。他们的结论可能是对的，但就他们所知而言，也可能是错的：他们从来没有设身处地地站到与他们想法不同的人的立场上，考虑这样的人可能会说些什么；因此，在任何真正的意义上，他们都不了解自己所宣称的那个学说。他们不了解这个学说中那些解释并证明其余部分的部分；不了解那些说明一个看来与另一个事实相冲突的事实其实可以与之调和的考虑，也不了解那些说明在两个看来都很有力的理由中，应该取这一个而不取那一个的考虑。真理中那决定天平倾向、决定一个充分知情的头脑如何判断的全部部分，他们都很陌生；除了那些同样公正地关注过双方、并努力在最强有力的光照下看清双方理由的人以外，没有人真正懂得它。这种训练对于真正理解道德和人事问题是如此必不可少，以至于如果一切重要真理的反对者并不存在，那就必须把他们想象出来，并且为他们提供最高明的魔鬼辩护人所能想出的最有力的论证。