政黨體系理論中的「過度確定」問題－－結構、制度、策略及文化

The Overdetermination Problem in the Theory of Party Systems-Structure, Institution, Strategy, and Culture

政治學者在解釋民主政治體制中政黨體系變遷時，往往單就選舉制度的設計來討論其「機械效果…」對於選舉結果及政黨政治的影響，卻忽略選舉制度的作用高度受到「心理效果」的佔先影響。解釋上的缺點，除了「過度確定」的問題外，也將民主政治中政黨、候選人、選民、憲政體制和選舉制度的複雜動態關係，過度簡化成靜態的制度決定論，因而低估非制度性因素的影響。本文指出，要解決「過度確定」的問題，首先應將制度設計中「機械效果」和「心理效果」所能發揮的限度界出來，後再與其他相競逐的解釋進行比較，以釐清何者具有較關鍵的因果作用。

To explain the change of party systems in democracies, political scientists always resort to the interpretation of electoral results and party alignments by analyzing the mechanistic effects of the electoral rules, neglecting that the overall effects are highly affected by the psychological effects originating from the strategic interaction of voters, parties, and candidates. In addition to the overdetermination problem, such an approach fails to take into consideration the dynamic relationships between structure, institution, strategy, and culture. This failure has resulted in the underrating of non-institutional effects, reducing to a static institutional determinism. The author argues that the key to solve the above problems is to fist identify the limits of the mechanistic and psychological effects of the electoral rules. A comparison of competing explanations is then needed to clarify the explanatory power of each factor.