物理的なものの因果的閉塞性と心的因果 --その両立可能性の検討--

Abstract

In studying Mind - Body Problem, many scholars suppose the "closed character" of the physical world, which means that physical matter is never affected by consciousness. This supposition seems scientifically indubitable. Based on the supposition, some philosophers maintain that events of consciousness, if exist, must be determined by ones of brain. They say consciousness "supervenes" on physical matter as a base. While the closedness of the physical world seems obvious, it also seems obvious that mind events cause physical effects ("downward" causation). In this paper, I struggle with this contradiction. In the second section, I criticize Kim's concept of supervenience. Kim tries to make the closedness of the physical world and the downward causation compatible with each other. But I conclude that his "frontal" attack is not successful. I propose another option of the compatibility. While the physical closedness is on objective level, the "downward" causality is on subjective level. Might the "contradiction" of the two be avoidable, making use of this difference of the levels? Because physical system producing consciousness is a kind of "complex system", small changes in its initial condition give rise to big differences. Then, since we can not accumulate all physical information about a person in everyday life, we can not predict his/her physical movement from the physical information about the person. Though the "downward" causality is Subjective, it could not be reduced to physical causality. It is not only practical but also theoretical difficulty. (§ 3) I examine eliminativism next, because it is against my proposition that does not take mind reducible to matter. Then I reject eliminativism.(§ 4) However, my proposition has two serious difficulties. One is evolutional difficulty. According to my proposal, consciousness would have only subjective existence, and no function to live. But without adaptational merit, consciousness could not have survived.(§ 5) Another difficulty is the following: the supervenient theory that my supposition draws on has unexpected result, that supervenient consciousness would be newly produced every moment, and be momentary without continuity.(§ 6) These difficulties are invincible as long as we take the "downward" causality for a mere seeming one. That is, the "downward" causality must be real one. A breakthrough must be found by the rocky road, that is, we have to defeat the closeness of the physical theory and explicate the mechanism of the downward causation.