regions each with different forms of intense suffering, such as eight extremely hot hellish realms, eight extremely cold, being partially eaten alive, beating and other forms of torture in proportion to the evil karma accumulated. These beings are reborn in another realm after their evil karma has run its course, they die, and they get another chance. This realm is not similar to afterlife hell in Christianity, states Damien Keown, because in Buddhism there is no realm of final damnation and existence in this realm is also a temporary state. Cause and end Samsara is perpetuated by one's karma, which is caused by craving and ignorance (avidya). Karma Samsara is perpetuated by karma. Karma or 'action' results from an intentional physical or mental act, which causes a future consequence. Gethin explains: In the Buddhist view, therefore, the type of birth one has in this life is determined by actions or karma from the previous lives; and the circumstances of the future rebirth are determined by the actions in the current and previous lives. Craving and ignorance Inconsistencies in the oldest texts show that the Buddhist teachings on craving and ignorance, and the means to attain liberation, evolved, either during the lifetime of the Buddha, or thereafter. According to Frauwallner, the Buddhist texts show a shift in the explanation of the root cause of samsara. Originally craving was considered to be the root cause of samsara, which could be stilled by the practice of dhyana, leading to a calm of mind which according to Vetter is the liberation which is being sought. The later Buddhist tradition considers ignorance (avidya) to be the root cause of samsara. Avidya is misconception and ignorance about reality, leading to grasping and clinging, and repeated rebirth. According to Paul Williams, "it is the not-knowingness of things as they truly are, or of oneself as one really is." It can be overcome by insight into the true nature of reality. In the later Buddhist tradition "liberating insight" came to be regarded as equally liberating as the practice of dhyana. According to Vetter and Bronkhorst, this happened in response to other religious groups in India, who held that a liberating insight was an indispensable requisite for moksha, liberation from rebirth. The ideas on what exactly constituted this "liberating insight" evolved over time. Initially the term prajna served to denote this "liberating insight." Later on, prajna was replaced in