In the traditional Buddhist view, moving between this life and rebirth is not a random act, but is determined by the actions in your current life. In this manner, you would be the heir to your own actions. As Peter Harvey says in An Introduction to Buddhism, if you commit acts of hatred — violent acts, such as murder, rape, incest, or bodily harm — you will be reborn into a life in hell. Here again the question arises whether this hell is meant literally or metaphorically. Unskillful or unwholesome actions of hatred and aggression leave one in a state that is very much like hell. You are trapped in a hot place of emotion with no hope for escape. You are blinded by rage, and out of control. That sounds like hell.
On the night of the Buddha’s enlightenment he is said to have remembered 100,000 past lives. How is such a statement to be interpreted? How critical is a belief in rebirth to the early teachings of the Buddha? The cultural milieu of ancient India during the Buddha’s time involved a vast and colorful universe of gods and goddesses. The Buddha speaks of gods and devas in his sermons, but he did not see them as godlike in the common sense of gods. These gods were trapped in samsara just as humans.
Rebirth is a fertile metaphor. It is not necessary to believe in rebirth to be a Western Buddhist or to derive benefit from the Buddha’s teachings. On the one hand, as a metaphor, rebirth is a potent concept about the cycles of experience that occur right here and now. On the other hand, Tibetan Buddhists take the concept of rebirth literally and base much of the culture, beliefs, and rituals on this possibility.
Whether metaphor or actual, “rebirth” occurs in every moment during this lifetime. When you breathe, your breath goes through a cycle of birth and death. As you move through life, you go through cycles of thought and emotion; everything is constantly changing. This is the cycle of becoming and when characterized by greed, hatred, and delusion, leads to neverending cycles of suffering. The goal of Buddhist practice is to become liberated from these cycles of becoming that infiltrate every moment of life.
You may be wondering, if there is no self and no soul, what is it that takes rebirth? How can karmic fruits be carried into a next life? The personality of “me” and “mine” does not persist, but the mental energy or samskaras are what Buddhists would say persist in the form of impersonal consciousness. That energy is what, for instance, the Tibetan Buddhists believe takes rebirth.
However, if human birth is considered be “precious” and rare, you might be wondering what the universe was doing for billions of years before human beings evolved? The idea that human life is precious seems a bit humanocentric, given the vast expanse of geological time where humanity is but a blink, unless this notion of linear time is dispensed. Again, the issue is whether you can derive benefit from the Buddha’s teaching without having to take these ideas literally. The answer is a resounding yes.
However, the notion of rebirth may be congenial to you. The Buddhist notion of rebirth is different than other concepts of reincarnation that you may be familiar with. Since there is no personal essence, “you” cannot experience rebirth. Something carries forward but it is not your personality or “soul.” You can think of it like a candle flame. One candle flame can light another candle. The flame “passes” to the next but has a unique identity. Within the system of birth and rebirth, there were considered to be many worlds and many ways in which one could be reborn — endless worlds and endless ways to be reborn.
Whether conceived of actual rebirths or rebirth into the next moment, these cycles involved not only human births. A person was not necessarily born as a human in every lifetime. There are also animals, spirits, gods, titans, and the inhabitants of hell. The early Buddhists rejected the Hindu caste system, so in rebirth it was possible to move from a god to a human, an animal to a god. There was no safety in reaching a higher life form. Every life form was subject to death and therefore rebirth. Most Buddhists in the Western world would take these realms and forms as being metaphorical or mythical.