....It wasn’t until about 600 BCE, just before the time of the Buddha, that Upaniṣadic ideas were condensed into the Sāṃkhya system. And it’s upon the Sāṃkhya system that the different systems of yoga, those that recognised Vedic authority (Vedanta), and others that do not - Buddhism, Jainism and Charvaka-materialism, - base their arguments.