In developing a plausible alternative, my operating assumptions and guiding philosophy will be resolutely naturalistic, materialist, and non-dualist. I assume only a single universe of interconnected phenomena, a universe devoid of souls, spirits, mental essences, and the like. In particular, persons, on this account, are not possessed of any essential core identity (an indivisible self or soul)
"When I die I won't go to heaven or hell, there will just be nothingness." Asimov's naturalistically based skepticism about heaven or hell is common among secularists... but he commits an equally common fallacy in his blithe assumption about nothingness, namely that it could "be." By substituting nothingness for heaven and hell, Asimov implies that it awaits us after death. Indeed the word itself, with the suffix "ness," conjures up the strange notion of "that stuff which does not exist."
"It might be nice to believe such a theory, but isn't the truth starker? This life is the only existence there is; afterward there is nothing." Although he probably doesn't mean to, with these words Nozick may suggest to the unwary that "nothing" is something like a state into which we go and never return
Although the fear of death is undoubtedly biological and hence unavoidable to some extent, the fear of nothingness, of the black abyss, can be dealt with successfully. This involves seeing, and then actually feeling, if possible, that your death is not the end of experience. It is the end of this experiencer most definitely, but that end is not followed by the dying of the light. Experience, I will argue, is quite impervious to the hooded figure who leads his unwilling charges into the night.
For the subject, awareness is constant throughout life; the "nothingness" of unconsciousness cannot be an experienced actuality.
The second question ("What's next?") is a little trickier, because, unless we suppose that my death is coincident with the end of the entire universe, we can't responsibly answer "nothing." Nothing is precisely what can't happen next. What happens next must be something, and part of that something consists in various sorts of consciousness. In the very ordinary sense that other centers of awareness exist and come into being, experience continues after my death. This is the something (along with many other things) which follows the end of my particular set of experiences.
As I tried to make clear above, subjectivities--centers of awareness--don't have beginnings and endings for themselves, rather they simply find themselves in the world...Of course we know that they are not always in place from an objective standpoint, but their own non-being is never an experienced actuality for them.
I propose that we should anticipate the subjective sense of always having been present, experienced within a different context, the context provided by those subjectivities which exist or come into being.
So when I say that you should look forward, at death, to the "subjective sense of always having been present," I am speaking rather loosely, for it is not you--not this set of personal characteristics--that will experience "being present." Rather, it will be another set of characteristics (in fact, countless sets) with the capacity, perhaps, for completely different sorts of experience. But, despite these (perhaps radical) differences, it will share the qualitatively very same sense of always having been here, and, like you, will never experience its cessation.