While there is no convincing evidence for meditation in pre-Buddhist early Brahminic texts, Wynne argues that formless meditation originated in the Brahminic or Shramanic tradition, based on strong parallels between Upanishadic cosmological statements and the meditative goals of the two teachers of the Buddha as recorded in the early Buddhist texts. He mentions less likely possibilities as well. Having argued that the cosmological statements in the Upanishads also reflect a contemplative tradition, he argues that the Nasadiya Sukta contains evidence for a contemplative tradition, even as early as the late Rig Vedic period.
What contains evidence for a contemplative tradition?
Nasadiya Sukta