The evidence for the human soul is in the power I have to consciously interact, manipulate, control and create. I am not nature's puppet.
It's odd how much this sounds like gnosticism, which also tried to distance humans from nature, and exalted a non-natural component. They tended to say that the divine spark is trapped in the body, from where it could be liberated, but unfortunately, this gave the body a definite negative slant, and you get the condemnation of the 'carnal' in various writers. But you also find this in Christianity.
Also strange is the pick-up of this by various New Age ideas, which also aimed for the spirit and downgraded the earth and the body. Not all of them actually.
I would think that paganism has had a rebirth, partly to redress the balance and go back to nature.