薩維奇確定性原則的邏輯與認知分析

摘要： 薩維奇將確定性原則作為其決策理論體系的一條重要公理,以確保決策者的偏好具有一致性。然而,確定性原則遭到了阿萊悖論等諸多難題的挑戰(zhàn),致使期望效用理論的合理性遭到質(zhì)疑。從認知的角度看,確定性難題可以由框架錯覺、不恰當?shù)膯栴}情境、非結(jié)果主義推理方式等非理性因素所導(dǎo)致。從邏輯的角度看,確定性難題源于人們錯誤地將確定性原則當作了一個邏輯原則。因而,在運用確定性原則時,必須注意它的應(yīng)用條件和適用范圍,或者引入非線性的決策權(quán)重以建構(gòu)起更加具有解釋力的權(quán)重效用理論,從而實現(xiàn)對確定性難題的消解。
To keep preferences of decision maker consistent,Savage introduces the sure-thing principle as one of the most important axioms in the axiomatization decision theory. However,the sure-thing principle has been challenged by Allais Paradox,etc.,then the rationality of expected utility theory as well. In fact,the sure-thing principle is the principle of rational choice only,but not logically necessary. For the solution of sure-thing puzzle,we can either take care of its conditions,or replace the decision probabilities with decision weights. By decision weights,we can develop the weighted utility theory,such that it is more expressive than expected utility theory.