為什麼統一天下的是秦國？「歷史制度主義」對「新古典現實主義」的補充

Why Was It the Qin, and Not One of the Other Six Warring States, That Unified Ancient China? -Supplementing the Theory of Neoclassical Realism With Historical Institutionalism

由於秦國的變法成功，戰國時代以秦國併吞六國、統一天下的結局告終。其中的謎題在於，事實上當時所有的七個大國都曾經先後有過變法圖強的嘗試，但為什麼只有秦國的變法能夠成功呢？本文認為，文獻中的觀點，對於「為何秦國可以延續變法，而其他六國卻無法做到」的問題，無法提供一個令人滿意的解釋，唯有透過比較政治理論中的「歷史制度主義」的一個重要概念─關鍵轉折，來補充國際關係理論中的「新古典現實主義」的論點，才能夠區別出能夠同時解釋秦國與其他六國的成敗差異的真正原因。由於秦國的建國過程與其他六國的建國過程的初始差異（關鍵轉折），秦國成為當時受到西周王朝封建制度的影響最小的大國之一，因此秦國的貴族與六國的貴族有著較為不同的利益結構，秦國的貴族不僅與國家的發展有著較為直接的利害關係，對於土地制改革與軍功制改革的反感也不如六國的貴族那樣厭惡，因此當一個允許平民能夠透過「耕」與「戰」的良好表現而進入貴族階級的改革方案出現之時，秦國貴族對於新法本身的反對就遠不如六國貴族的那樣強烈，因而在新法能夠成功地使秦國的「私人報酬」與「社會報酬」連結起來、並證明其有效且符合當權者利益的情況之下，新法得以很快地在秦國獲得了得以自我強化的政治基礎。這個歷史制度主義的重要概念，解釋了為什麼只有秦國能夠成功延續其富國強兵的變法，而其他六國在面對崛起的秦國時為何難以做到「內部制衡」的關鍵原因。本文的發現，對「新古典現實主義」的理論架構補充了一個在文獻中較少提及的因果關係，也對「歷史」、「比較政治理論」和「國際關係理論」三者之間的連結提供了一個初步的貢獻。

Due to the Qin’s successful agricultural and military institutional reforms, the Warring States Period ended with unification under the Qin. However, the enduring puzzle is that even though all of the seven major powers had adopted reforms that were aimed at enriching their countries and strengthening their armies, why was the Qin the one to ultimately succeed? This study argues that none of the common explanations found in the literature offer a satisfactory answer to this puzzle, and that it is better understood by supplementing the international relations theory of neoclassical realism with the concept of “critical junctures” emphasized in the historical institutionalist approach of the comparative politics field. Because the Qin experienced a different “critical juncture” from the other six great powers at the beginning stages of its nation-building process, and as a relatively newly-established state that was not influenced by the Western Zhou Dynasty’s feudal arrangements as much as the other six great powers, the Qin had an aristocratic system and interest structure that were different from the other great powers. While the nobles of the other great powers had vested feudal interests in land and in the military that emphasized the legitimacy of bloodlines, Qin nobles emphasized farming and military merit more and ascribed less value to the importance of bloodlines. As a consequence, when Shang Yang promoted a new institutional reform which allowed common people to be promoted to the nobility class according to their performance in farming and warfare, Qin nobles did not resist the reform as much as the nobles in the other great powers did. After the reform was instituted and it was successfully demonstrated that the private rate of return matched with the public rate of return, and that it worked in making the Qin a prosperous country with a powerful army, the reform soon became self-enforcing. This “critical juncture” concept explains why the Qin was able to achieve profound institutional reforms while the other six great powers failed in internally balancing against the rising Qin. The findings of this study not only supplement neoclassical realism with a new causal factor that was long neglected in the literature but also provide an preliminary contribution to the interdisciplinarity among the fields of history, comparative politics, and international relations.