When people speak of rebirth in Buddhism they may not think there is more to it then simply dying and being born again. There are, however, many realms to the rebirth process. These realms are often depicted in the “wheel of life”. The three lowest realms are similar to the concept in Christianity of purgatory. So at the bottom is hell, but the Buddhist hell, although similar, is unlike the Christian hell in two respects. The first is that it is not a place of final damnation, because it is a temporary state from which a person will eventually be released. The second difference is that in Buddhism there are both hot hells and cold hells, where the suffering is due to freezing rather than roasting. Above
hell is the animal realm, which is undesired because their intellect is no match for humans, and also because they are hunted by humans. Above the animals is the realm of ghosts. These are unhappy spirits that hover around the fringes of the human world and can sometimes be glimpsed as shadowy forms. For the most part, ghosts are former human beings who developed strong attachments, which keep them bound to the earth. They are consumed by desires they can never satisfy. The fourth level is that of the Titans, a race of demonic warlike beings at the mercy of violent impulses. Motivated by a lust for power they constantly seek conquests in which they find no fulfillment. On the fifth level is the human world. Rebirth as a human being is regarded as both highly desirable and difficult to attain. Human beings have reason and free will, and can use these to understand the other realms of suffering.
Karma can be either good or bad, but Buddhists speak of good karma as “merit.” Much effort is expended in acquiring it, and one of the best ways for a person to earn merit is by supporting the order of monks. This can be done by placing food in the bowls of monks as they pass on their daily alms round, by providing robes for the monks, by listening to sermons and attending religious services, and by donating funds for the upkeep of monasteries and temples. To do good deeds simply to obtain good karma would be to act from a selfish motive, and would not earn much merit. Also, in many Buddhist cultures there is a belief in “merit transference’”, or the idea that good karma can be shared with others. Donating good karma has the happy result that instead of one's own karmic balance being depleted, it increases as a result of the generous motivation in sharing.
Mahayana cosmology decided that the Buddha has “three bodies” or exists in three dimensions: earthly, heavenly, and transcendent. The earthly body (Nirmanakaya), was the human body he had on earth. It is a physical, mortal body, like that of any human being. His heavenly body (Sambhogakaya), is in a blissful realm located somewhere “upstream” from the world we now inhabit, not unlike the Christian heaven. This body is located in a splendid paradise. The transcendent body (Dharmakaya) was the Buddha thought of as identical with ultimate truth, in some respects not unlike the way Christian mystics and philosophers have spoken of God as the “absolute” or ultimate reality. You can see that with these three different forms the Buddha, there are different beliefs that go along with each. The human form allows you to relate to the Buddha on a more personal basis, trying to show that he is simply also just human; the heaven form shows that the Buddha is above us, and that he needs to be looked upon as superior, and the transcendent form allows us the image of the Buddha as more than just superior, but as something that should have our complete and total worship, it’s the form of God.