Patanjali defines contemplation ("Dhyana") as the mind process, where the mind is fixed on something, and then there is "a course of uniform modification of knowledge". Bronkhorst states that Buddhist influences are noticeable in the first chapter of the Yogasutras, and confirmed by sutra 1.20 because it mentions asamprajnata samadhi is preceded by "trust (sraddha), energy (virya), mindfulness (smriti), concentration (samadhi), and insight (prajna)". According to Bronkhorst, "the definition of Yoga given in the first chapter of the "Yoga Sutra" does not fit the descriptions contained in the same chapter," and this may suggest the sutra incorporated Buddhist elements as described in the four jhanas. Wynne, in contrast to Bronkhorst's theory, states that the evidence in early Buddhist texts, such as those found in "Suttapitaka", suggest that these foundational ideas on formless meditation and element meditation were borrowed from pre-Buddha Brahamanical sources attested in early Upanishads and ultimately the cosmological theory found in the Nasadiya-sukta of the Rigveda.