Is it possible to have different dimensions of different timelines? For example there could be a dimension on this earth, but being taking place in the future or past, and maybe there are dimensions like this constantly being created. So if humans all die on earth in this dimension we would all just start all over in a new dimension still on this earth. That could explain things like people seeing "ghosts". For example it could be just two dimensions accidentally getting two close to each other (kinda like when you are switching through channels on the radio and you're in between two of them and you get that noise kind of sound) and then you kind of see a person from a different dimension, but you can see through it because you're not actually in that dimension. Just something I thought of. Maybe it's just far beyond our understanding...

Perhaps, this is not real life, but merely a dream or fantasy state of mind. The shadows or ghosts are waking thoughts as we return to the real world, we do not remember in this dream.

Perhaps, you are not even real, you, and/or this post is just in my imagination and your thoughts as you read this, are merely my ideas of what you would think.

Maybe there are different dimensions. Maybe ghosts are just people that died that have nowhere else to go because they can't cross to a different place. Maybe there is no different place/dimension for them to cross to. Maybe ghosts don't even exist.

Who knows?

No one has been able to prove that ghosts exist, or that God exists, that heaven exists, that different dimensions exist.

So really, your question isn't unique at all. It's been asked before. Sadly, there's no answer, at least no real answer. There's no proof that anything other than our daily lives, and death, exist.

You're asking for an answer based on belief, and only belief. Some will believe what you do, others will not. It's a lot like religion and believing in God. It's all about faith, and really, no one can tell you if your beliefs are real or not.

I don't know if you are right or not, but sounds as plausible as the Great Spaghetti Monster to me, or any other theory on reality of which there are many opinions.