One can even stop just short of solipism and consider the possibility that humans are the only consciousness in the universe.
Granted, this is just a possibility, perhaps a very small one. But we know so little about such things.
My point is that you may have far more of an effect on Consciousness than you think.
We still have no objective definition of consciousness that would let us determine what it is that would be evidence that consciousness exists, on or off of Earth.
You're playing a trick there by jumping from brain to atoms, but people do not define themselves by their atoms, but by their consciousness which will not survive death making what you're saying about all being one rather meaningless. So..
> so for all practical purposes, you are immortal.
Not even close, because I cease to exist the second my brain dies and whatever happens to my atoms after my mind is gone is completely meaningless.
That is not how the vast majority of people define "immortal".
Unless you're aiming for some kind of uplifting, motivational speech?
I see meaning as something not like a hard drive, where you store data once you are done, but like RAM, where you read, write and modify on the fly, constantly, while the machine is powered on.
Sure, at some point the machine will be powered off you'll be gone, but meaning doesn't have to be everlasting to exist and have an impact.
I prefer this perspective because it avoids self importance - an attribute that in my opinion does more harm than good.
Whether or not they continue to exist in some other reality has no bearing on the fact that you exist now, thanks to them.
If there is an afterlife, I'm immortal. Thus again meaning exists, this time so in accordance with your definition thereof.
Therefore, meaning exists.
Any meaning, that's is defined while one is mortal is no more than illusion, in which people immerse themselves for whatever reason.