If there were to be a conscious existence after death, it would, so it seems to me, have to continue on the level of consciousness attained by humanity, which in any age has an upper though variable limit.
There are many human beings who throughout their lives and at the moment of death lag behind their own potentialities and even more important behind the knowledge which has been brought to consciousness by other human beings during their own lifetimes.
Hence their demand to attain in death that share of awareness which they failed to win in life.
I have come to this conclusion through observation of dreams about the dead. ~Carl Jung, Memories, Dreams and Reflections.