Forget the silly Thomas's who ask for proof. The spiritual life is a mystical one and as such beyond the mind. Frankly, if a Yogi tried to tell you of his inner experience, he will only scare you.
The spiritual life is a personal journey. You have to do the work that all scriptures East and West speak of: Prayer, selfless service; the belief or Faith in a Higher Entity; Gratitude ... spiritual things are spiritually discerned. I cannot travel your Path and you cannot travel mines. Yoga or the spiritual life, is a process of inner transformation of one's own nature. The cleaner your own mirror, the cleaner you will see and understand God's universe. Continue ...much peace.