""A lot of scholars maintain that no belief in transmigration had existed before the Upaniṣads. However, Killingley presented evidence that shows that the topics of the pañcāgnividyā and deva-/pitṛyāna [two concepts in the Upaniṣads] have their antecedents in the earlier Brahminic texts. He claims that theories of karma and rebirth are made up of several ideas already present in Vedic thought. Also Tull shows that the conceptual framework of the Upaniṣadic idea of transmigration had been established already in the Brāhmaṇas with their idea of sacrifice during which the sacrificer symbolically experiences death and rebirth during his journey to heaven. Oberlies goes even further back and tries to reconstruct a possible Rgvedic belief according to which the dead came back to earth to be reborn in their progeny. We can put this belief into broader conceptual frames as it is very close to the beliefs characteristic of 'small scale' or 'tribal' societies. Obeyesekere maintains that the belief in rebirth after death is quite widespread and varies in different cultures. Contrary to the mature Upanisadic form of the rebirth eschatology, the rebirth eschatologies characteristic of small scale societies are not linked to ethical causation. Obeyesekere believes that the kṣatriyas in the Upaniṣads who expound their views about transmigration implicitly are in discussion with traditions that 'seem to believe that after death one can be reborn in the human world or in a subhuman one'" (p.183-84)."