1. The economic center of Europe moved from Mediterranean to the former Black Forest region (Germany) outside the domain of Roman Empire even at its peak. The equivalent for east Asia would be if Japan had succeeded in developing Manchuko into the industrial center of east Asia, would Manchuko (extending beyond today's northeast China into the forests of eastern Siberia and the flat grass and shrub lands of central Siberia) be able to unify east Asia? The geographic equivalent of China in Europe is Italy: the Alpine mountains is the equivalent of the Great Wall. Romans managed to expand imperial administration beyond the boundaries set by mountains and seas, whereas China didn't (the conequest of Lingnan / Guangdong was made possible by rivers from Sichuan and Guizhou (YeLangGuo). China didn't even conquer the off-shore islands like Taiwan and Japan, or the peninsulas like Korea and souteast Asia. Italy did "reunify" in the lat 19th century, not necessarily for the better. The tribesmen coming out of the East Asian black forests did "reunify" China: the Manchus, but their reign was shorter than the Frankish Empire and the Holy Roman Empire. 2. If you want to discuss why Europe was not unified, there are two factors: geography and active balance of power players. Unlike the flat lands in the middle of China with all rivers flowing from west to east, Europe has moutains in the middle with no single river flowing across the entire land. Asia as a continent is not unified for a similar geographic reason. Europe also benefited from having major islands nearby: the British Island was only 21 miles away, and the water way separating Sweden from Danmark is even narrower, whereas Taiwan was 100 miles from the continent; so that off-shore powers could help maintaining balance of power on the European continent, but not in East Asian until industrial age when Japan prevented unification of East Asia by Russian Empire, then the US prevented unification of East Asia by Japan. 3. Running a government is expensive; the bigger the government the more expensive and the more inefficient. Large empires are only possible when there is large accumulated wealth to burn. So Chinese history was replete with wealth accumulated during fragmentation periods being burned throuth the unified periods. Just like Roman period burned through the wealth accumulated during Greek and Phoenician period, and the unification period under Mao burned through the wealth accumulated during the "Warlordism" fragmentation period, and a mere decade+ of recent central planning burning through the wealth accumulated during the previous 3 decades of emphasizing local "special zones."
我认为汉字对于中国人的民族认同感,具有独特的作用。中华帝国从秦以来,历史上并非没有分裂过,分裂时期也是不同国家相互敌对打得死去活来上百年。但是下一个统一王朝中,来自不同国家的遗民却可以互相认同是同种同族,直到下一次分裂。这种独一无二的“分久必合合久必分”的历史,我认为汉字的作用不可忽视: 如果中文的书写系统并不是汉字而是拼音,我们会发现,比如说“你好”,在普通话是 Ni Hao,在粤语是Nei Hou,相似,但不同。与英语的 Good Night以及德语的Gute Nacht,甚至荷兰语的goedenacht,就几乎能够对应上。而有些方言里,也有特殊的词汇,如果只用拼音,也会完全不明白对方在说什么。所以,如果完全拿掉汉字,按照欧洲拼音文字的标准,其实中文的各个方言,在官话内部可能还可以算是方言,但官话和粤语、闽南语等,其差异完全可以和葡萄牙语与西班牙语,或者乌克兰语与俄罗斯语之间的差异相当了。也就是说日常交流,即使用拼音写下来,也很难互相理解,但如果语言学家来研究,就会发现官话和粤语语法相似(其实并不是完全一致),而且大部分词汇同源。但中文的神奇之处,就在于两种方言,光是说,不允许说普通话,恐怕可能90%都理解不了,但只要写下来,就反过来90%都能理解了。 但我们可能会忽略了中文是一种非常特殊的存在,像中文这种发音可以变化很大,但写法几千年变化很小的文字(hologram,之所以不说表意文字,是因为中文字在一定程度上表音,虽然音的历史漂变可以非常大),是目前所有存世的文明中绝无仅有的。古埃及象形文字和玛雅文字都属于hologram,但中文是唯一还在非常活跃地使用的表意文字。 而且,正是因为汉字的存在,使得我们阅读古代一两千年以来的文献,没有太大的困难,所以中国的历史文化传承很好。另一方面,因为秦始皇的书同文,使得即使经历了五代十国、南北朝这种超越几代人的大乱世,在下一个大一统王朝的时候不同地区的人民仍然能够有非常强烈的民族认同感。试想欧洲的诸民族,其实很多都是同源的,只是在经历了分裂战乱之后,就逐渐走向了不同的发展路线,最后形成了不同的民族,语言也发生了漂变。其中一个很大的原因,就是因为没有像汉字这样的超越时间和空间的文化之锚。