The world picture of the Buddhist Pali Canon is a mythical world picture. The world is made up of 31 planes of existence, divided into a formless realm, a fine material realm and a sensory realm. In the formless realm dwell purely mental beings; in the fine material realm dwell most of the devas (gods, angels). Some devas also inhabit the higher planes of the sensory realm; we humans live in the middle planes; and in the lower planes we find the hungry ghosts (pretas) and hell dwellers. Life is a cosmic cycle of death and rebirth between these planes, with movement upward and downward determined by the good or bad nature of one’s actions within each plane. The results of these actions affect not only the circumstances of our new birth, but also our actions and mental states in the new life, which reflect the previous ones. All of this takes place on a cyclical time scale of endless recurrence, of decline followed by renewal and more decline: once upon a time human beings lived for 80 000 years, and their lack of virtue slowly reduced this, so that now their lifespan is merely a hundred, and it will eventually decline to ten.
All of this is mythological talk, and the individual motifs may be traced to the contemporary mythology of Jainism and the Upaniṣads. Insofar as it is mythological talk it is incredible to men and women today because for them the mythical world picture is a thing of the past. Therefore, contemporary Buddhist proclamation is faced with the question of whether, when it invites faith from men and women, it expects them to acknowledge this mythical world picture of the past. If this is impossible, it then has to face the question whether the Pali Canon’s proclamation has a truth that is independent of the mythical world picture, in which case it would be the task of Buddhist theology to demythologize the Buddhist proclamation.
The words above are not mine. I have pulled these two paragraphs directly from the beginning of New Testament and Mythology, by the 20th-century German Protestant theologian Rudolf Bultmann, and simply replaced what is specifically Christian with Buddhist concepts. But I think Bultmann’s argument stands just as well when it is transposed into a Buddhist key.