According to the Buddhist tradition, karma evolves right at the beginning of ego, when basic bewilderment develops. The basic bewilderment is the development of a sense of separateness, a sense of me and other. At that very moment, when that occurs, the volitional action of karma is created. The analogy for the creation of karma is that it's like making a clay pot with the help of the continual turning of a potter's wheel. You throw clay on the wheel, and the clay becomes a pot. The constant struggle to maintain oneself is like the continual rotation of the potter's wheel. Trying to solidify our actions for our security is like throwing the clay on the wheel. Then, the pot or the cup that we make is creating our own coffin. We have created our own heaven or hell—whichever it may be.
Condensed from “Karma and Rebirth” Talk Six of The Tibetan Buddhist Path, an unpublished seminar given at Naropa University, June 22, 1974. Edited from the transcript.