B .C . with the speculative philosophy of the Upanishads . Salvation was sought , not through sacrifices and rites , but through knowledge . Six schools of Hindu philosophy arose , the most important being those of Yoga and Vedanta . In the sixth century B .C . Jainism and Buddhism arose as reform movements within Hinduism but both became separate religions . Nearly all the sects and cults respect the Vedas (``revealed knowledge , the ancient collections of religious writings . The Rig-Veda , whose origins probably go back to...