To me, the human soul calls for no evidence, it's a brute fact. I'm here right now, consciously experiencing, assumably so are you, and no more needs to be said.
Although philosophical inquiries into the nature, source, and properties of mind have been useful exercises for many people, I don't think much is gained by refusing to accept the sentient 'I' axiomatically, and assuming it nonexistent or illusory until it can be explained, analyzed, or logically justified. Fans of the Analytical School of philosophy and cutting edge academic philosophy of mind (the heirs to Logical Positivism's legacy), will probably consider me a killjoy for saying this, but so be it. I've gained nothing valuable for living a better and more connected life by holding back from affirming soul / self / mind / atman / etc, and although I'm not against others doing it if they so choose, I'm not in much position to recommend it.