Central to Zoroastrianism is the emphasis on moral choice, to choose the responsibility and duty for which one is in the mortal world, or to give up this duty and so facilitate the work of "druj". Similarly, predestination is rejected in Zoroastrian teaching and the absolute free will of all conscious beings is core, with even divine beings having the ability to choose. Humans bear responsibility for all situations they are in, and in the way they act toward one another. Reward, punishment, happiness, and grief all depend on how individuals live their lives.