- 哲学 (ISSN:03873358)
- vol.2012, no.63, pp.201-216_L11, 2012 (Released:2012-10-16)
It is generally thought that the motivation for an action can be explained in terms of a desire (or evaluative judgment) and a belief. It is not clear, however, what kind of explanation is the explanation of the motivation for an action. This paper takes up and considers the validity of two answers to this question from different perspectives: the causal theory of action and the anti-causal theory of action. Construing practical reasoning as a simple practical syllogism, Donald Davidson argues that the motivation for an action can not be fully explained by the rationality of practical reasoning and needs to be explained by the causal relation between a beliefdesire pair and an action (the causal theory of action). Practical reasoning, however, can not be construed as a simple practical syllogism. An agent should be construed to start with a prima facie judgment about the desirability of an action and to work to reach an all-things-considered (ATC) judgment before reaching a conclusion in practical reasoning. Under such a construal, Davidson's argument that the rationality of practical reasoning can not fully explain the motivation for an action loses its validity (the anti-causal theory of action). It appears prima facie, however, that the causal theory of action is required for explaining the motivation for an akratic action. An akratic action is a free action that is contrary to an ATC judgment about the most desirable action reached at the time of performing it, and it is thus generally considered that the motivation for an akratic action is not determined by practical rationality. Rather, it is more plausibly determined by causal powers of individual desires (or evaluative judgments). Under the causal theory of action, however, an akratic action can not be construed as a free action since, under the theory, an akratic agent is a passive being who is at the mercy of the causal power of desires and hence does not have autonomy in the sense of a capacity to determine his/her motivation voluntarily, which is required for a free action. In order for an akratic action to qualify as a free action, it must be an action that is contrary to a comprehensive ATC judgment and, at the same time, arises because of a cognitive-condition-bound ATC judgment in favour of it. Furthermore, the motivation of an action, in general, must be explained by a practical rationality that includes cognitive-condition-bound ATC judgments (the anti-causal theory of action).