"The Christian asks you to believe in his religion, to believe in Christ and to believe in him as the incarnation of God, to believe in a God, in a soul, and in a better state of that soul. If I ask him for reason, he says he believes in them. But if you go to the fountain-head of Christianity, you will find that it is based upon experience. Christ said he saw God; the disciples said they felt God; and so forth. Similarly, in Buddhism, it is Buddha's experience. He experienced certain truths, saw them, came in contact with them, and preached them to the world. So with the Hindus. In their books the writers, who are called Rishis, or sages, declare they experienced certain truths, and these they preach. Thus it is clear that all the religions of the world have been built upon that one universal and adamantine foundation of all our knowledge - direct experience. The teachers all saw God; they all saw their own souls, they saw their future, they saw their eternity, and what they saw they preached."

- Swami Vivekananda, "Introductory" (Dec 14, 1895, New York Vedanta Society), Raja-Yoga, Complete Works: Vol 1