- 医学哲学 医学倫理 (ISSN:02896427)
- vol.33, pp.30-40, 2015-09-30 (Released:2018-02-01)
We are afraid that our non-existence continues forever after our death. Lucretius spoke on this fear, stating, "Because no one fears the eternal nonentity which is in front of our birth, it isn't also necessary to fear the eternal nonentity in our after death," as a way to convince people to be rid of this fear. This statement is called Lucretius' "symmetry argument". Yet despite this, almost all modern debaters have insisted that the relation between pre-birth non-existence and post-mortem non-existence is asymmetrical. The main purpose of this article concerns the following two points about this statement of asymmetry; namely, that this statement is premised on a specific view of metaphysics and that the meaning of the claim of asymmetry must be examined from a viewpoint of metaphysics as it relates to time and the world. In this study, I first pointed out that the opinion of debaters included the assumption that we ourselves could identify non-existence. Next, I pointed out that the disputants would actually be insisting that the dead continue to exist in some form. Third, I examined which specific theories on time from twentieth-century analytic philosophy suited the disputants' opinion, and found that no ideas on time were entirely consistent with their view. Lastly, I examined non-existence before birth and non-existence post-mortem from a viewpoint of the possible worlds semantics of analytic philosophy. From this, both non-existences are located in their own possible worlds, and in addition to this, there is the real world in which the subject is alive. My examination concluded that there is a difference in existence qualification between a possible world and the real world, but that there was no such difference between two possible worlds. This suggests that the relationship between pre-birth non-existence and post-mortem non-existence is neither symmetrical nor asymmetrical.