Thinking about death. One particular death. A sad and lonely death.
Dying is a lonely business. No matter if we are surrounded by family, or perhaps medical staff, when we go we go alone. No one can come with us. It is only "I" -- my consciousness -- that ends.
I have read somewhere that "My Death" is a difficult topic for philosophers to grapple with, in part because it is such a difficult thing to imagine the world without "I". I think I understand their problem -- I find it incomprehensible that people would voluntarily end their consciousness*. Even if you imagine the world going on without you, almost inevitably it's still from "your" POV, like an imagined movie you're watching.
I remember being something like 10 years old, getting ready for bed one night, when for whatever reason I was suddenly struck by the idea of death as the end of "I". It was terrifying -- I literally saw in my head a black curtain in front of me, marking the absolute end of Everything as far as I was concerned.
Sir Fred Hoyle, the astronomer, introduced an idea in one of his SF novels that was an early form of the many-worlds postulate. He proposed a wall of uncountably numerous pigeonholes, each pigeonhole containing a slip of paper with a message written on it. The messages are descriptions of moments from one's life. Every so often a clerk comes along and shines a flashlight into the pigeonholes, and that light is what we experience as consciousness. The messages also contain information about other message slips, but whereas the messages describing the "past" are correct, the ones describing the "future" are fuzzy, because the future is indeterminate. And there is no limit to how many times the clerk can come and illuminate the pigeonholes, so inevitably our consciousness appears to continue. This is not unlike how, in the parallel universes postulate, every time a choice is made the universe splits into x and not-x, resulting in a continuously branching array of similar but subtly different universes; x could represent "death", so every time we escape a situation that could have resulted in our death, inevitably our consciousness continues on in the universe in which we survived. I myself clearly remember three occasions in my childhood when I could have fallen off a cliff to my death (what is it with me and cliffs?). I suppose in those other universes where I did plummet off those cliffs, things are much the same, except I no longer exist there.
*Well, except perhaps in cases of unbearable torment. Like being stuck in one of my versions of Hell, as described elsewhere in the blog.