Background The Sloka 1.4 of Brhadharanyaka Upanishad traces the evolution (ati-sRsti) from Atma's ichha to split Purusha to the evolution of manuSya. This evolution is a series of 'Pancha mahA yajnA' which I talked about earlier (1). Brahma Yajna, which is the Cosmic inflation epoch, Deva Yajna which is upto Quark Epoch, Bhuta Yajna which is upto Matter domination epoch, Pitr Yajna which is upto evolution of macromolecules that have desire to have offspring (and hence called Pitr) and manuSya yajna which is upto evolution of Human beings (who can reside in a place and grow food). The pancha mahA yajnA In each of the Yajna, there is a Purusha which is 'dark', 'invisible', 'witnessing', 'catalytic' and not taking part. There is a pazu, which is the visible part. The visible part undergoes the sacrifice. The result of the Yajna (sacrifice), the Havis, is newer forms that did not exist before. In Brahma Yajna, Purusha is dark energy ...