realms of birth – such as heavenly, human, animal, hellish and others – occurs in the same way that a flame is transferred from one candle to another. Buddhaghosa attempted to explain rebirth mechanism with "rebirth-linking consciousness" (patisandhi). The mechanistic details of the Samsara doctrine vary within the Buddhist traditions. Theravada Buddhists assert that rebirth is immediate while the Tibetan schools hold to the notion of a bardo (intermediate state) that can last at least forty-nine days before the being is reborn. In Mahayana Buddhist philosophy Samsara and Nirvana are seen as the same. According to Nagarjuna, an ancient Indian philosopher, and a teacher of Mahayana Buddhism, "Nothing of Samsara is different from Nirvana, nothing of Nirvana is different from Samsara. That which is the limit of Nirvana is also the limit of Samsara, there is not the slightest difference between the two." Realms of rebirth Buddhist cosmology typically identifies six realms of rebirth and existence: gods, demi-gods, humans, animals, hungry ghosts and hells. Earlier Buddhist texts refer to five realms rather than six realms; when described as five realms, the god realm and demi-god realm constitute a single realm. The six realms are typically divided into three higher realms (good, fortunate) and three lower realms (evil, unfortunate). The three higher realms are the realms of the gods, humans and demi-gods; the three lower realms are the realms of the animals, hungry ghosts and hell beings. The six realms are organized into thirty one levels in east Asian literature. Buddhist texts describe these realms as follows: There are six Enlightened Buddhas that exist in each of the six realms. These six Buddhas have also been known as the "Six Sages." Their names are Indrasakra (Buddha in the god realm), Vemacitra (Buddha of the petty god realm), Sakyamuni (Buddha in the human realm); Sthirasimha (Buddha in the animal realm), Jvalamukha (Buddha in the hungry ghost realm), and Yama Dharmaraja (Buddha in the hot hell realm). Gods realm: the gods (devas) is the most pleasure-filled among the six realms, and typically subdivided into twenty six sub-realms. A rebirth in this heavenly realm is believed to be from very good karma accumulation. A Deva does not need to work, and is able to enjoy in the heavenly realm all pleasures found on earth. However, the pleasures of this realm lead to attachment (Upādāna), lack of spiritual pursuits and therefore no nirvana. The vast