In Buddhist philosophical thinking, pratityasamutpada is an explanation of the continuous processes of causation that create the cycle of rebirths. A simple explanation of pratityasamutpada is that no thing or thought exists eternally and of itself; everything that exists arises in dependence on causes and conditions, and passes away, producing further effects. Buddhist logic posits twelve links in this cycle of causation, beginning with ignorance and ending with death. These links are depicted as the outer circular band in the Wheel of Life paintings.