柏拉图

    柏拉图(约公元前429-347)是苏格拉底最杰出的弟子。柏拉图一生致力传播和发展苏格拉底的思想，继续撰写其对话录。对话录中，苏格拉底总是以主要谈话人的身份出现。这个著名的寓言选自《国家篇》，描述了达到理念王国的艰辛历程。《国家篇》是柏拉图著作当中读者最多的一部，对西方思想产生了十分深刻的影响。

    我说：这里有一个寓言，它说明我们本性可能达到的聪明或蒙昧程度。想象人们住在一个地下洞穴之中的情形，一个出口通向光明，一条漫长的通道引向洞内。他们从小到大一直都在那里，腿上和脖子上套着锁链，身体不能移动，脑袋不能转动，眼睛只能看到正前方的东西。在他们后上方某处，闪动着火焰的光亮；在这些囚徒和火焰之间是一条小径，一道矮墙顺着小径修建，就像演木偶戏所用的遮布，矮墙把演员的身体隐蔽起来，木偶在他们的头上表演。

他说：我明白了。

现在，想象在矮墙后面有人举着各种各样的人造物品，其中包括木制或石质的人和动物的形象，这些物品从墙头上露出来。自然，这些人有的在说话，有的不出声。

他说：奇怪的画面，奇怪的囚徒。

我回答说：就象我们自己，首先，处在这种受限制状态之下的囚徒既看不见自己，也看不见同伴，能够看到的只有火光投射到他们正前方墙面上的那些物品的影子，对不对？

对，如果他们的头一生中从来都无法转动，他们看不见。

他们也看不见在他们身后移动而过的那些物品。

当然看不见。

那么，如果他们可以互相交谈，能不假设他们所谈的就是那些在他们眼前晃动而过的影子吗？

他们必然会这样。

假设正对他们的那一面牢墙能产生回音，那又会如何呢？当他们身后的某个人讲话，囚徒们只能认为那是在他们眼前移动而过的影子发出的声音。

毫无疑问。

那么，无论从哪个方面讲，这样的囚徒只会将那些人造物品的影子当作实在的东西。

必然如此。

如果用以下方式释放他们，纠正他们的愚蠢看法，你想想会出现怎样的情形。假设他们中有一人获得自由，被迫突然站立起来，转过身体，仰视火光朝前走；那么，所有这些动作对他来说都会是痛苦的，他会感到眼花缭乱，无法看清他从前只见影子的那些物品。如果有人告诉他，他以前所见都是毫无意义的幻觉，而现在他离实在近了一些，面对更为真实的物品，看见的东西更为真实，你认为他会怎样回答？再进一步假设，让他看看那些以前从他身后移动而过的物品，让他一一说出它们是些什么。他不会感到困惑，不会认为眼前的东西并没有自己以前看见的那些影子真实吗？

是的，他会认为这些物品没有那些影子真实。

再者，如果让他直接看那火光，他不会感到双眼疼痛，因而试图逃避，把目光转回自己看得清楚的那些影子，认为它们比呈现在他面前的物品更为真实吗？

肯定会的。

再假设，有人强拉他顺着通道向上，走出洞穴，见到外面的阳光之后才放开他。当他身处阳光之下，发现强列的光线使自己的眼睛无法看清任何一个刚被告知是真实的事物，这样做不会使他感到痛苦和气愤吗？

他一时肯定无法看清。

这时，他需要时间适应，使自己能够看清上面世界的事物。首先，看清物体的影子最容易，接着是看水中人和物体的倒影，最后才是看物体本身。然后，与在白天直接观察太阳和阳光相比，在晚上观察天体和天空，看月光和星星也更容易。

是的，肯定如此。

最后，他将能够观察太阳，审视其本性，不是它在水中或其他任何介质中的影子，而是在天上的实实在在的太阳。

毫无疑问。

这时，他将会得出结论：正是太阳本身产生理性，产生一年四季，控制可见世界中的一切，而且在某种程度上也是他和他的同伴们曾经看见的一切东西的成因。

显而易见，他最终会得出这一结论。

这时，如果他想到其他囚徒，想到在原来住处被当作智慧的东西，他一定会对自己的变化感到高兴 ，为那些囚徒们的境遇感到难过。某个囚徒在观察移动而过的影子时目光敏锐，清楚地记得它们出现的顺序，能猜测到什么将会出现；囚徒可能有互相表示尊敬和赞赏的习惯，会对他给予种种奖励。我们这位获释的囚徒是否会对这样的奖励艳羡不已呢？是否会对这位在洞穴里受到尊重，拥有权利的人表示嫉妒呢？他不会有荷马笔下的阿基里斯的感觉，宁可“在凡界的穷人家当奴仆”，宁可忍受任何艰难困苦，而不愿重返旧念，重过原来的生活吗？

对，他宁可面对任何命运的摆布，也不愿再过那样的日子。

设想他返回地下，重新坐到自己原来的地方，设想一下将会出现怎样的情形呢？他的眼睛突然脱离阳光，将会充满黑暗。他可能会再按照要求说出自己对那些影子的看法，与那些从未获得过自由的囚徒们竞争；而那时他的视觉仍旧模糊不清，欠缺稳定，需要一些时间才能适应黑暗。囚徒们会嘲笑他，说他上去后回来反而失去了视力，因此谁也不值得花功夫想到地面上去。如果他们能抓住想要释放他们、将他们引出洞穴的人，他们会杀了他。

对，他们会的。

亲爱的格洛肯，这个寓言的每个特征都符合我们前面的分析。监狱住处相当于我们视觉所达的范围，洞中火焰的光亮相当于太阳的力量。你可以把上升到地面、观察世间万物的行程，看作灵魂升华、进入理性王国的旅程；这样，你就掌握了我所推测的意义，那就是你希望了解的东西。上天知道这是否是真实的；但无论如何在我看来就是这样。在知识的世界里，极善的原形是最终也是最难感悟到的东西。人们一旦感悟到它，就必然得出这样的结论：这是一切正确和善良事物的成因；在可见世界中，它产生了光和光辉之主，同时在理性世界中也拥有至高无上的地位，是理性和真理之源。离开了对这个原型的感悟，没人能够理智地行事，个人生活与国家大事概莫能外。

The Allegory of the cave--Plato

    Plato (ca. 429 - 347 B. C. ) was Socrates' most brilliant disciple. Until his death, Plato taught and developed the thought of Socrates and continued to write the dialogues, in which Socrates is almost always portrayed as the principal speaker. This famous allegory, taken from the Republic, depicts the struggle to reach the realm of ideas. As Plato’s most widely read work, it has exercised a profound influence upon Western thought.

    Next, said I, here is a parable to illustrate the degrees in which our nature may be enlightened or unenlightened. Imagine the condition of men living in a sort of cavernous chamber underground, with an entrance open to the light and a long passage all down the cave. Here they have been from childhood, chained by the leg and also by the neck, so that they cannot move and can see only what is in front of them, because the chains will not let them turn their heads. At some distance higher up is the light of a fire burning behind them; and between the prisoners and the fire is a track with a parapet built along it, like the screen at a puppet show, which hides the performers while they show their puppets over the top.

    I see, said he.

    Now behind this parapet imagine persons carrying along various artificial objects, including figures of men and animals in wood or stone or other materials, which project above the parapet. Naturally, some of these persons will be talking, others silent.

    It is a strange picture, he said and a strange sort of prisoners.

    Like ourselves, I replied; for in the first place prisoners so confined would have seen nothing of themselves or of one another, except the shadows thrown by the fire-light on the wall of the Cave facing them, would they?

    Not if all their lives they had been prevented from moving their heads.

    And they would have seen as little of the objects carried past.

    Of course.

    Now, if they could talk to one another, would they not suppose that their words referred only to those passing shadows which they saw?

    Necessarily.

    And suppose their prison had an echo from the wall facing them? When one of the people crossing behind them spoke, they could only suppose that the sound came from the shadow passing before their eyes.

    No doubt.

    In every way, then, such prisoners would recognize as reality nothing but the shadows of those artificial objects.

    Inevitably.

    Now consider what would happen if their release from the chains and the healing of their unwisdom should come about in this way. Suppose one of them was set free and forced suddenly to stand up, turn his head, and walk with eyes lifted to the light; all these movements would be painful, and he would be too dazzled to make out the objects whose shadows he had been used to see. What do you think he would say, if someone told him that what he had formerly seen was meaningless illusion, but now, being somewhat nearer to reality and turned towards more real objects, he was getting a truer view? suppose further that he were shown the various objects being carried by and were made to say, in reply to question, what each of them was. Would he not be perplexed and believe the objects now shown him to be not so real as what he formerly saw?

    Yes, not nearly so real.

    And if he were forced to look at the fire-light itself, would not his eyes ache, so that he would try to escape and turn back to the things which he could see distinctly, convinced that they really were clearer than these other objects now being shown to him?

    Yes.

    And suppose someone were to drag him away forcibly up the steep and rugged ascent and not let him go until he had hauled him out into the sunlight, would he not suffer pain and vexation at such treatment, and, when he had come out into the light, find his eyes so full of its radiance that he could not see a single one of the things that he was now told were real?

    Certainly he would not see them all at once.

    He would need, then, to grow accustomed before he could see things in that upper world. At  first it would be easiest to make out shadows, and then the images of men and things reflected in water, and later on the things themselves. After that, it would be easier to watch the heavenly bodies and the sky itself by night, looking at the light of the moon and stars rather than the Sun and the Sun's light in the daytime.

    Yes, surely.

    Last of all, he would be able to look at the Sun and contemplate its nature, not as it appears when reflected in water or any alien medium, but as it is in itself in its own domain.

    No doubt.

    And now he would begin to draw the conclusion that it is the Sun that produces the seasons and the course of the year and controls everything in the visible world, and moreover is in a way the cause of all that he and his companions used to see.

    Clearly he would come at last to that conclusion.

    Then if he called to mind his fellow prisoners and what passed for wisdom in his former dwelling-place, he would surely think himself happy in the change and be sorry for them. They may have had a practice of honouring and commending one another, with prizes for the man who had the keenest eye for the passing shadows and the best memory for the order in which they followed or accompanied one another, so that he could make a good guess as to which was going to come next. Would our released prisoner be likely to covet those prizes or to envy the men exalted to honour and power in the Cave? Would he not feel like Homer's Achilles, that he would far sooner " be on earth as a hired servant in the house of a landless man " or endure anything rather than go back to his old beliefs and live in the old way?

    Yes ,he would prefer any fate to such a life.

    Now imagine what would happen if he went down again to take his former seat in the Cave.  Coming suddenly out of the sunlight, his eyes would be filled with darkness. He might be required once more to deliver his opinion on those shadows, in competition with the prisoners who had never been released, while his eyesight was still dim and unsteady; ant it might take some time to become used to the darkness. They would laugh at him and say that he had gone up only to come back with his sight ruined; it was worth no one's while even to attempt the ascent. If they could lay hands on the man who was trying to set them free and lead them up, they would kill him.

    Yes, they would.

    Every feature in this parable, my dear Glaucon, is meant to fit our earlier analysis. The prison dwelling corresponds to the region revealed to us through the sense of sight, and the fire-light within it to the power of the Sun. The ascent to see the things in the upper world you may take as standing for the upward journey of the soul into the region of the intelligible; then you will be in possession of what I surmise, since that is what you wish to be told. Heaven knows whether it is true; but this, at any rate, is how it appears to me. In the world of knowledge, the last thing to be perceived and only with great difficulty is the essential Form of Goodness. Once it is perceived, the conclusion must follow that, for all thing, this is the cause of whatever is right and good; in the visible world it gives birth to light and to the lord of light, while it is itself  sovereign in the intelligible world and the parent of intelligence and truth. Without having had a vision of this form no one can act with wisdom, either in his own life or in matters of state.