Reincarnation

I often wonder about reincarnation. I mean it isn't part of the Judeo-Christian doctrines, well unless you're a Witness because they believe in the physical resurrection of the human body which they probably don't see as reincarnation. But still, I wonder.

One of the things that is supposed to be the case is that there are more humans alive now than before in the whole of human history, so where did all the new souls come from? Unless it's true that humans can be upgraded from animals, in which case, where does the souls start? Is there soul to inanimate things on this planet? All part of the same substance kind of thing.

What about ghosts and spirits, why haven't they been reincarnated?
It would be a bit harsh if you lived a blameless life once and were then reincarnated as a being whose circumstances made them evil.

Science-Fiction deals with this question a lot. The Cylons for example, in Battlestar Galactica, in spite of being machines, have reincarnation off to a fine art, their non-physical selves can cross space instantly when the body dies and be resurrected in a new body.

In Richard Morgan's 'Altered Carbon' world, human consciousness can be simply downloaded into a new 'sleeve'. Very confusing because you retain your memories of your previous sleeve. Morgan has his hero who has previously been a man, wake up in the body of a woman just about to menstruate, that pretty much puts us in his hero's head loud and clear. And you can carry on torturing someone ad nauseam because everytime you kill one sleeve, you can download the consciousness into a new one.

Greg Bear in his 'Eon' world, describes human life extended by downloading into a computer simulation or a created ectoplasmic form. I suppose that technically this isn't reincarnation since there is no flesh, but the identity is retained in a different form.

There are aspects of the idea of reincarnation that I find comforting, others that I don't. Some mediums who believe in it tell us that souls have an attraction to souls they have known in a previous life, like a pack instinct for souls.
If there is other life in the universe, would they share our stock of souls? Could we be reincarnated as them and they as us?

Too many questions, but then it's the questions that enrich our lives, partly because of the intellectual stimulation they imply, but partly because they insist on being asked and to ask a question is to interact with another.