Lucretius’ Symmetry Argument

1. My previous pre-vital nonexistence is not, and was not, bad for me.
2. My previous pre-vital nonexistence is relevantly similar to my forthcoming post-mortem nonexistence—that is, just as it is true to say that my going out of existence sooner than I might have means that I will end up having done less, having experienced less, having accomplished less, etc. than I otherwise would have, so it is also true to say that my coming into existence later than I might have means that I will end up having done less, having experienced less, having accomplished less, etc. than I otherwise would have. 
3. Therefore, my forthcoming post-mortem nonexistence is not, and will not be, bad for me.