The Buddha was able to perceive how beings passed from one existence to another, and how their circumstances changed in accordance with their deeds. He saw that all these existences, both the happy and unhappy periods, were of a temporary nature and subject to perpetual change. In the ancient Pali language, in which the word of the Buddha is preserved, this unsatisfactory and uncertain state of affairs is termed Dukkha loosely translated as 'suffering'. According to the Buddha, all existence in the universe, including living beings, is in a state of flux or change. All sentient beings are subject to a cycle of birth, growth, decay and death.
Death is followed by rebirth and the cycle is repeated indefinitely.
The principal reason for this, the Buddha said, is the lack of understanding of the true nature of things, which allows beings to engage in actions that perpetuate the process. The understanding referred to here is not just book knowledge, but an intuitive experience, gained through long mental and spiritual development, which helps beings to relinquish desires. Such powerful desires perpetuate the cycle of existences. This process is often symbolically represented in Buddhist art by a wheel-the Wheel of Life. Karma and Rebirth Karma, which literally means 'action', produces results in accordance with the principle of cause and effect.