In Patanjali's Raja Yoga, also called "meditation yoga", dhyana is "a refined meditative practice", a "deeper concentration of the mind", which is taken up after preceding exercises. In Hinduism, dhyāna is considered to be an instrument to gain self-knowledge. It is a part of a self-directed awareness and unifying Yoga process by which a world that by default is experienced as disjointed, comes to be experienced as Self, and an integrated oneness with Brahman. The Brahman has been variously defined in Hinduism, ranging from non-theistic non-dualistic Ultimate Reality or supreme soul, to theistic dualistic God.