The debate on the existence of God cannot be resolved on the basis of proof. While atheists claim that theists fail to prove that God exists, theists respond by saying that atheists fail to prove that he doesn't. Atheists would then say that the burden of proof lies on him who asserts and not on him who denies, and theists would point out that saying there is no god is also a positive claim that equally requires proof.
The reality of disembodied souls would necessarily overturn everything we know about physics. Any scientist would be itching to find evidence for the supernatural—evidence that never seems to turn up, despite the most adamant and most confident protestations of believers.
Every conscious thing we do or choice we make is somehow motivated by the pursuit of pleasure or the avoidance of pain. The only variables are the kinds of things that bring varying degrees of pleasure and pain to each individual, the premises on which expectations of pleasure or pain are based, and the ability to delay gratification.
If religious traditions have been completely wrong about what goes on in the universe, why would they suddenly be unquestionably correct about what goes on in the mind?