Taoism is the only cultural system that focuses on immortality in the here and now. Every other culture believes in immortality in some other form and shape after the body has been left behind. Ironically, there is no way to prove that there is an immortal soul or spirit since all other cultural systems claim it is only possible to experience in the "after-life." However, taoists claim that immortality must be an experience you can have in your current body. After millenia of year and telling people that immortality is possible with your own body now, if there wasn't substancial proof for this claim, would Taoism still exist?
See the following videos and you decide: Taoist Immortality
and see my personal experience with a Taoist Immortality Elixir