ヒュームの自然主義

──信念と道徳心情にそくして──

抄録

In this paper, I take up Hume's theories of causation and morality, in particular, his accounts of belief and moral sentiment, and consider what his naturalism really amounts to.
Hume treats causal reasoning and belief basically as a non-reflective reaction caused by custom. Hence he naturally attributes causal reasoning and belief not only to humans but also to animals. Causal reasoning and belief are mental operations, he thinks, which have their foundation in the nature shared by humans and animals.
In so far as Hume explains the formation of moral sentiment in terms of sympathy viewed as a mechanism of contagion, his account of moral sentiment is on a par with his account of belief. However, Hume does not attribute moral sentiment to animals, because he does not suppose that animals are capable of reflective thinking, which he regards as essential for the formation of moral sentiment properly so called. Now the process of reflective thinking involved in the formation of moral sentiment can be seen as a process of self- and mutual-understanding of human nature. For example, we understand and mutually understand the fact that a certain degree of selfishness is inseparable from human nature, thereby correcting the sentiment of blame we naturally have toward those who oppose our self-interest. However, a process such as this has no definite end point. It is true that Hume tries to give a psychological explanation of moral phenomena and show that morality is an expression of human nature, but this is not all he does in his naturalism. He also has in his view the openended character of morality and the possibility of its transformation.