非化約的物理論能解釋心理現象的因果作用嗎？

Abstract

心靈實在論、物理的因果封閉性原則和心靈因果的存在三個設理能否同時成立？如果主張心靈因果作用存在與心靈實在論，會導致物理因果封閉性原則的失敗。如果主張物理因果封閉性原則，則心靈實在論需要更強的支持，心靈因果作用的存在也會受威脅。做為一個物理論者如何能同時接受這三個設理，而不至於導致矛盾呢？這是本文要處理的問題。 Kim是所有哲學家中，將心理現象的因果問題最成熟呈現的人。Kim用這三個主張產生的衝突，來論證心靈因果作用不存在，真正的因果作用只發生在物理層次，所以化約論為真。本文檢討Kim的論證，主張Kim並未解決心靈因果作用的問題。 也有哲學家例如Baker主張物理的因果封閉性原則是錯的，因果是知識論的問題，而不是形上學的問題，所以心靈的因果作用存在；她的因果主張接近Hume，所以必須承繼Hume的所有困難。本文不同意Hume將因果視為心理習慣的見解。 我認為心靈實在論、物理的因果封閉性原則和心靈因果的存在，這三個主張皆為真，它們所導致的衝突只是表面上的矛盾。這個表面矛盾之所以產生，是在於對因果關係這個概念的認知上有錯誤。只要提出往下之因果作用的新解，就可以成功解釋心理現象的因果問題。本文將發展Searle的生物自然主義，和往下之因果作用的新解，來解決心理現象的因果問題。

Could these three theses, mental realism, the physical causal closure principle and mental causation jointly be consistent with each other? It seems that mental realism and mental causation will result in the failure of the physical causal closure principle. On the other hand, the physical causal closure principle will threaten the other two theses. In this thesis I am concerned with the problem of how to make these three theses consistent. Kim is a philosopher who has done the best in dealing with the issue of mental causation. He rejects the existence of mental causation, because he thinks there is a paradox among the three theses. He argues that the real causal interaction happens only at the physical or brain level. For Kim, reductive physicalism is the best we can have. What I will do is to examine Kim’s argument, and I argue that he did not solve the problem. Some philosophers such as Baker reject the physical causal closure principle. According to Baker, causation is an epistemological principle, not a metaphysical doctrine. The existence of mental causation is an unnecessary worry. This view is similar to Hume’s position, so it has to face the same problems that Hume has to deal with. I do not accept the view that the causation is just psychological habit. I will assume that, these three theses are all true. And I will argue that the paradox derived from them is just a surface contradiction. I will contend that a proper theory of the downward causation can successfully solve the problem of mental causation. This thesis develops Searle’s biological naturalism and a new approach to the downward causation. By doing that, I will argue that the problem of mental causation can be resolved.