著者

和田 利博

出版者

日本西洋古典学会

雑誌

西洋古典學研究 (ISSN:04479114)

巻号頁・発行日

vol.53, pp.114-124, 2005-03-08

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In Democritean atomism, all atomic motion is forced by blows of other atoms On the contrary, Aristotle demanded an explanation for why, if there was no natural motion for atoms, there was any motion for them at all In response to this criticism, Epicurus introduced the downward fall of atoms by their own weight as a natural motion for them But if all atoms only fall downwards at equal speed, why is there any collision amongst them at all ? This is just why the atomic swerve was introduced as another natural motion for atoms in Epicurean cosmology Now, according to Cicero, Epicurus introduced the atomic swerve to avoid a necessary motion by atom's own weight that he himself has introduced with the intention of improving upon Democritean atomism However, the fear arising from this necessity is that if all atoms were only to fall downwards, since there would be no collision amongst them, no compound body would be formed On the other hand, Diogenes of Oenoanda represents the atomic swerve in Epicurean atomism as counterevidence to a necessary motion by collisions amongst atoms in Democntean atomism And the fear arising from this necessity is that if all atoms were only to collide with one another, since the soul too is composed of them, no voluntary action would exist If that is the case, the testimony that the necessary motion by atom's own weight hinders the voluntariness of action by governing the mind is inaccurate Therefore, the interpretation that the atomic swerve ensures the voluntariness of action by freeing the mind from such a necessity is mistaken To sum up, in Epicurean atomism, the atomic swerve plays the following two roles (A) In his cosmology, the atomic swerve prevents the atom's own weight from causing all things (including all actions) not to occur by the blows of other atoms and makes a beginning of collisions amongst atoms, (B) In his theory of action, the atomic swerve prevents the collisions amongst atoms from causing all actions to occur exclusively by the blows of other atoms and breaks a chain of collisions amongst atoms (though it does not hinder collision itself, needless to say) Incidentally, Epicurus divides all things into three categories and contrasts necessity with chance and what depends on us And since the atomic swerve was exactly introduced to avoid necessity, it must be either chance or what depends on us However, there is much evidence suggesting that the atomic swerve is uncaused motion Judging from this, it is inevitable to conclude that the atomic swerve is a kind of chance Nevertheless, I suppose that the atomic swerve need not be the alternative of chance or what depends on us but can be either of them as the case may be That is, it is just the atomic swerve occurring even without the soul that Epicurus called chance in a general sense And what depends on us eventually means the action that has the atomic swerve occurring within the soul at the beginning of motion