哲學家對於什麼是行動有不同的看法：戴維森認為，一個身體運動是一行動，當且僅當，它是由一組可以合理化主體之行動的信念、欲望、意圖所引起的，而法蘭克福認為，一個身體運動是一行動，當且僅當，它是在主體的引導下發生的，以及，一個身體運動是一蓄意行動，當且僅當，主體是藉由滿足自己的某個意圖而引導這個身體運動。戴維森和法蘭克福對於行動的主張雖然不同，但是，戴維森所說的行動，以及法蘭克福所說的蓄意行動，顯然都是由主體的某些信念、欲望、意圖所引起的。費爾曼也贊同這種行動是由主體的某些信念、欲望、意圖所引起的之標準說法，然而，費爾曼卻不滿意只以信念、欲望、意圖來解釋行動，他認為這樣的標準說法忽略了主體對於自己的行動的影響力，因此，他試圖去尋找除此之外的某個能夠顯示出主體在行動中發揮了影響力的心理事件或狀態。
費爾曼所找到的、能夠顯示出主體在行動中發揮了影響力的心理事件，是主體想要讓自己依據最佳理由而行動的高階欲望，他認為他找到的這個高階欲望，將能補足戴維森和法蘭克福未能賦予主體在行動中一個合宜地位的缺失。不過，戴維森和法蘭克福是否真的沒把主體對於自己的行動的貢獻算進去呢？他們是否事實上已經說到了主體對於自己的行動的影響力，只是費爾曼沒看到而已？這是本文所要探討的主要問題。
對於這個問題，我的看法是：戴維森認為欲望是一種評價性判斷，有證成行動的效力，因此，他確實無需再額外地找出某個可以說明主體的影響力的心理事件或狀態，至於法蘭克福所說的二階決意，亦是有此功能，因為，當主體被二階決意選定的欲望所推動時，推動他去行動的欲望既是他認同的，他便藉此發揮了對於自己的行動的影響力，而且，由於認同會牽涉到一種決定，二階決意不可能是外在於主體的，因此，當主體據此二階決意而行動時，他是主動地而非被外力介入地去行動。

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