这部分讨论了在最后一波淘汰大浪中留下的人的特点及出路。不是靠选举，是经历过种种理论及现实考验还能留下来的

Those that survive, scarred and fifty, sobered and self-reliant, shorn of scholastic vanity by the merciless friction of life, and armed now with all the wisdom that tradition and experience, culture and conflict, can coöperate to give — these men at last shall automatically become the rulers of the state.
那些幸存者，伤痕累累且年届五十，清醒且自立，被生活无情的磨砺剥去了学术上的虚荣。如今他们已武装上所有智慧，这些智慧是由传统与经验、文化与冲突共同协作铸就的。——这些人最终自然而然而将成为理想国的统治者。

细节解析

1、scarred: deeply affected or marked by mental or physical pain or injury 伤痕累累
He also addressed the plight of children scarred by conflict.他还强调了儿童身处的困境，两国间的冲突已使他们伤痕累累。
2、sober: to make (someone) serious or thoughtful头脑清醒
I knew then that the shock had partially sobered him.那里我知道震惊已经让他部分清醒了。《漫长的告别》
3、self-reliant：confident in you own abilities and able to do thing for yourself; not needing help from other people 自主的；自力更生的
John Bunsby, himself, a man of forty-five or thereabouts, vigorous, sunburnt, with a sprightly expression of the eye, and energetic and self-reliant countenance, would have inspired confidence in the most timid.《八十天环游地球》
4、shorn: diminished; deprived of被剥夺了……的；被剥去……的
The boundary was fixed, and Michigan, though shorn of some of the land she claimed, came into the union in 1837.边界是固定的，密歇根虽失去了部分土地，但在1837年加入了联邦。《美国历史》
5、merciless: having or showing no mercy; very cruel or harsh残忍的；冷酷无情的
But all these things went down before the merciless coldness of her mind and the goad of desperation. 但所有这些在她心里头无情的冷酷和绝望的刺激面前都让步了。《飘》
6、friction: the force that causes a moving object to slow down when it is touching another object摩擦
There are a lot of friction, there was a lot of tension.有许多摩擦，关系也很紧张。《乔布斯如何改变世界》

所在段落

The Story of Philosophy《哲学的故事》第1章Plato第7节VI. The Psychological Solution第17段第7句：

Alas! Not yet. Their education is still unfinished. For after all it has been, in the main, a theoretical education something else is needed. Let these Ph.D.'s pass down now from the heights of philosophy into the "cave" of the world of men and things; generalizations and abstractions are worthless except they be tested by this concrete world; let our students enter that world with no favor shown them; they shall compete with men of business, with hard-headed grasping individualists, with men of brawn and men of cunning; in this mart of strife they shall learn from the book of life itself; they shall hurt their fingers and scratch their philosophic skins on the crude realities of the world; they shall earn their bread and butter by the sweat of their high brows. And this last and sharpest test shall go on ruthlessly for fifteen long years. Some of our perfect products will break under the pressure, and be submerged by this last great wave of elimination. Those that survive, scarred and fifty, sobered and self-reliant, shorn of scholastic vanity by the merciless friction of life, and armed now with all the wisdom that tradition and experience, culture and conflict, can coöperate to give — these men at last shall automatically become the rulers of the state.
浙江大学译本：那些幸存者，饱经风霜且年届五十，头脑清醒并自力更生，学者的自负已被残酷的生活打磨得一干二净，他们有着传统、经验、文化和竞争共同给予的智慧一这些人最终将自然而然地成为理想国的统治者。

整段

这段写了最后大淘汰的原因、内容及结果。那些在淘汰考验中留下的人，并是理想国的统治者。

Last and sharpest test

上句见：Day429