No one has ever actually seen a soul (have they?) and I've never heard of any reliable evidence being produced to prove otherwise, so it would be fair to say that they don't exist. Even if someone could see souls, and was able to determine where they went, there would be so many greenfly souls, worm souls, bacterium souls...flying around everywhere that they would have an impossible job. Oh, and "Thousands of years ago, some unknown person said souls exist, and they wrote it down so it must be true..." does not count as reliable evidence. No such thing!