Everyday yoga at home on Not exactly a theme, but characteristic of the Upanisad as a whole, is the employment of Samkhya terminology in the description of the individual and of the cosmos. Purusa, ksetrajna, buddhi, ahamkara are all used in 2.4-5. The description of the atman in 2.7 is also reminiscent of the Samkhya purusa, who is also characterized as a spectator, rather than the atman of earlier Upanisads, who is described as the inner controller (antaryamin), though note that the Svetasvatara (which is also influenced by Samkhya), e.g. 1. Everyday yoga at home 2016.