以因果为工具与以因果为对象——珀尔与刘易斯的因果理论之辨

Causation as a Tool or Causation as a Target——The Analysis of Pearl’s and Lewis’Theory of Causation

珀尔的因果理论与刘易斯的因果理论在当今因果关系研究领域都具有重要地位,但学界对两种理论的差异与适用范围的讨论是不足的。通过使用珀尔的结构因果逻辑处理刘易斯因果理论遭遇的三大疑难,即“抢先”问题、“副现象”问题、“充分必要条件下倒果为因”问题,发现上述疑难都能被轻易消解。“轻易消解”的深层次原因是:在逻辑层面,珀尔认为“真值不影响因果关系”,而刘易斯认为“真值会影响因果关系”。这种逻辑层面的差异解释了珀尔和刘易斯因果理论的最大差异:以因果为工具与以因果为对象。珀尔的因果理论适合处理“因果工具型”问题,该类问题的特点在于默认了因果关系的存在;刘易斯的因果理论适合处理“因果对象型”问题,该类问题的特点在于不认为“因果”是一个可以不加分析而被使用的初始概念。

Judea Pearl’s and David Lewis’theory of causation both hold important positions in the field of causation studies,but it seems their difference and applicability still need to be compared and discussed.Using Pearl’s Logic of Structure-Based Counterfactuals,we analyze the three predicaments Lewis’theory of causation encountered,i.e.pre-emption,epiphenom-ena and cause-effect inversion,and show these problems can be answered easily with Pearl’s theory.This“easy answer”reveals the logic preferences of the two theories:Pearl believes“the truth value doesn’t influence the causal relation”,but Lewis insists“the truth value do change the causal relation”.Their logical preferences explain the major difference between Pearl’s and Lewis’theory of causation:causation as a tool or causation as a target.Pearl’s theory is more efficient to deal with the“tool-style”problems,which treats causation as a presupposed struc-ture?while Lewis’theory is more suitable for“target-style”problems,which reject causation as an initial concept and try to find its metaphysical grounding.