Buddhism developed initially in India as a reaction against Hinduism in the fifth century bce. It drew many of its beliefs from that religious context. Two key Hindu concepts that Buddhism uses are samsara and karma. Like Hinduism, Buddhism holds that life is a series of rebirths and "redeaths" in a continuous cycle and that a person's actions during a life produce karma that determines the place and form of the next life (and sometimes even succeeding lives). In Buddhism, samsara is often symbolized by the Wheel of Life. (For a picture of the Wheel with a fuller explanation, go here or here.)
In all forms of Buddhism, the realm of samsara is divided into three main levels: heaven, earth and hell. Both heaven and hell have a number of levels. Inhabiting these realms, are creatures in six different "states of existence" (or, six types of creatures). These are: gods, humans, asura (=ogres or titans), animals, hungry ghost and demons. Beings in one of the first three states are there because of their store of good karma. Beings in one of the last three states are there because of their store of bad karma. Gods exist in the higher heavens, asuras in the lower heavens and humans on earth. Animals dwell on earth, the hungry ghosts (so-called because they have large stomachs but tiny mouths) live between earth and hell, and the demons of course reside in hell.
One aspect of the Hindu world that Buddhism rejected was the caste system; in Buddhism all humans are essentially equal. Samsara therefore rotates souls through the different states of being rather than through different levels of the caste system.
The Buddha discussed the human problem and its solution together. The short statement that lays out these out--The Four Noble Truths--forms the main foundation of Buddhism that differentiates it from all other religions.
The first two Truths describe the problem:
All life is suffering and suffering comes from desire, because desire is so rarely fulfilled. It is important to understand these two statements together. By itself, "suffering" could refer to all kinds of suffering, such as suffering inflicted upon us by circumstances or by other people. The former could include suffering of sickness, age, accidents, while the latter could include malicious injury of a physical or emotional nature. But the Buddha makes it clear that although these are obvious forms of suffering, the most insidious forms of suffering are caused by desire, specifially, unfulfilled desire. Thus, although illness is suffering in-and-of-itself, it is suffering even more so because one desires to be well. While losing a spouse or lover is suffering by itself, it is compounded by the desire for them to be near.
Once the problem is set up in this manner, the solution becomes apparent:
The third Noble Truth is a logical deduction from the first two. Given the link between suffering and desire, the way to stop suffering is to stop desiring. But how to accomplish this? Here is the Buddha's contribution: the Noble Eight-Fold Path with its ultimate goal of nirvana. The Path's eight steps fall into three groups. First, a person must believe and intend the right things. Second, they must carry out those intentions in the community and society in which they live. Third, they must then turn their minds to higher things and practice meditation on the ultimate nature of reality. Finally, they perceive ultimate reality and know the correct belief concerning all things. (For a fuller discussion of the Noble Eight-fold Path, see the Religious Life page.)
Nirvana means "liberation" and refers to liberation from the realm of samsara. In many ways, the buddhist goal of Nirvana is similar to the Hindu goal of moksha. It is the way out of samsara--out of the cycle of rebirth and redeath. It is accomplished through meditation, and it is usually done by removing oneself from the regular activities of life. However, there is a key difference. Whereas Hinduism described moksha as the realization of the unity of the individual (atman) and the cosmic essence (Brahman), Buddhism sees nirvana as the extingushing of desire and hence the elimination of suffering. In Theravada Buddhism, this is the only religious goal and the person who experiences it is called an arhat. The single aim of Theravada is to help people become arhats and thus release them from samsara at their death. One then goes to a state of being outside (or beyond) the realm of samsara, that is, a state of being that has no form and no place.
Only a human being can attain nirvana. No other state of being, including that of god, can do so. While this is understandable for the three "evil" states of being, this is surprising for the gods. One explanation is that the gods live in such a state of bliss that they cannot conceive of suffering, and thus cannot realize the truth of the Four Noble Truths. Thus they must die and be reborn in human form to attain liberation.
The foundational idea of suffering, which is called dukkha in Buddhism, has two additional components that need to be discussed. If suffering refers to the character of a person's life within samsara, then first component--anatman--refers to an individual's life, while the second--anitya--refers to the character of samsara.
Anatman literally means "no soul." It refers to the buddhist belief that no living being has a permanent soul. Instead, humans, and other beings, are made up of five skandhas which come together at birth and fall apart at death. They are not reborn together again. These five skandhas are: the body, the feelings or emotions, the perceptions or thoughts, the intentions amd the consciousness.
The main ramification of this understanding of living beings is that there is no permanent soul that gets reborn from life to life. Thus, although Buddhism believes in reincarnation, it does not hold that any "thing" gets reincarnated. This leads to a conundrum that Buddhist monks have been discussing and debating for millennia, namely, to what does karma apply if nothing continues from one life to another? There is no clear answer for this question and the main reason is that the Buddha refused to supply one. He believed that his job was to tell people how to make the journey (to nirvana), not to describe the details of the sights along the way.
So what are we to make of this? On the one hand, the Buddha clearly knew his previous lives (indeed all arhats reach a stage of meditation where they can know their previous lives). This implies that there is some part of a person that continues from life to life. On the other hand, Buddhism clearly denies the existence of a soul. In fact, one of the ultimate realizations when a meditator nears nirvana is the understanding of non-dualism (i.e., that there is no difference between subject and object, between knower and that which is known).
The best explanation is a metaphor. One way to light a candle is to bring the flame of a burning candle to the wick. Once the two candles are burning, what is the relationship between the flame of the first and the flame of the second? They are not the same flame, yet one flame caused the other. It is the same with life, according to Buddhism. The karma of one life causes the next life, yet they are not the same life.
The second additional component of dukkha (suffering) is anitya, which is usually translate as "impermanence." It refers to the notion that everything is changing, nothing remains the same. Thus existence is impermanent, and because impermanence is what leads to suffering, existence is suffering.
One reason for all this suffering is ignorance, namely, ignorance of the true nature of reality. The answer to ignorance of course is wisdom. And true and complete prajna comes at enlightenment. The Buddhist word for enlightenment is "bodhi," which is the basis for the title "Buddha." He was the first to be enlightened and thus was called "The Buddha." The root meaning of bodhi is "to awaken"; thus the Buddha is the "Awakened One." The rest of humanity is asleep.
Enlightenment comes essentially one step before nirvana. It is the realizing of the true nature of the cosmos, the link between samsara and nirvana, and so on. It is at this point that one can view their past lives.
What has been described above are the earliest views of the buddhist cosmos and the human problem it creates. Theravada Buddhism continues these views in a fairly faithful manner. Mahayana Buddhism and succeeding forms of Buddhism add to this picture and change it in certain ways. To learn more, continue reading.
Mahayana Buddhism agrees with Theravada Buddhism that the human problem is suffering; it holds the Four Noble Truths as fundamental. But whereas Theravada holds out the ideal of the individual striving alone on the Eight-fold Path towards nirvana, Mahayana adds helpers who provide shortcuts and assistance out of compassion for those who are suffering. These helpers are called bodhisattvas, and are beings who have worked towards enlightenment and nirvana. But rather than enter nirvana, once they are able, they turn around and bring their store of wisdom, power and merit to help others along the same path. This simple idea has a number of ramifications for the goal of humanity.
Bodhisattvas can exist in two different planes, the earthly plane and "Buddha-fields." When people start on the path towards enlightenment, they are obviously in this world--the world of samsara. But once they attain enlightenment (and there are six stages known as paramitas on the way to nirvana), they pass out of samsara's bonds. But since they do not enter nirvana but remain to help others, they remain in the Buddha-fields "between" samsara and nirvana. The Buddha-fields are described in geographical terms; for example, Amitabha's Pure Land is in the west. And even though most lay people envision them in geographical terms, the monks and others who striving the path towards enlightenment see the symbolic character of this description.
The Buddha-fields contain an uncountable number of bodhisattvas and buddhas. For just as people rise to become bodhisattvas, bodhisattvas continue striving until they reach the final stage which is buddha-hood--the ultimate understanding of one's own buddha nature. There are thus many bodhisattvas and buddhas in the Buddha-fields that people can call upon. Here are three:
Mahayana introduces one more complication to this scheme, the nature of The Buddha himself. Mahayana envisions him as having three bodies, one in each of three realms of being. The first two realms we have already discussed, the realm of samsara and the realm of the Buddha-fields. The third is ultimate reality itself.
The Buddha's first body, his Dharma Body, corresponds to Ultimate Reality. That is, Buddha IS Ultimate Reality. Everything that is real and which truly exists is Buddha. There is no dualism. In the final analysis, then, there is nothing other than Buddha; all is unity, all is one thing. The Buddha's second body is called his Bliss Body. This is the form that the buddhas and the bodhisattvas take in the Buddha-field; those who have realized their true Buddha-nature is in essence a representation of Buddha. The Buddha's third body is that taken by the buddhas and the bodhisattvas when they enter the earthly realm. It is called the Transformation Body.
Pure Land Buddhism focuses on one aspect of the Mahayana cosmos and emphasizes its importance. Since the Buddha-fields are a "place" that is outside of samsara, even though it is not yet nirvana, it provides an opportunity for bodhisattva compassion to be expressed. In Theravada Buddhism, there is little opportunity for or expectation that the laity can get beyond the suffering of samsara and reach nirvana. The best they can hope for is to be born in the next life "as a monk" who can attain nirvana. Pure Land provides the laity with another option.
The Buddha Amitabha has created with his store of merit a "Pure Land" (a paradise) which is in the "Western" part of the Buddha-fields. Anyone who calls on Amitabha (=Amida) using the formula of the Nembutsu can enter this land upon death. Thus escape from samsara and suffering is available to the laity without extensive years of monkish discipline and meditation. Anyone who enters the Pure Land may stay there forever, or may return to human form in an advantageous birth that will enable them to reach nirvana within a lifetime. (For a site in praise of Amitabha, go here.)
Zen Buddhism focuses on a completely different aspect of the Mahayana cosmos, namely, the idea that everyone has a buddha-nature which is part of the Ultimate Reality of Buddha. Zen rejects all other aspects of Mahayana--the bodhisattvas, the other buddhas, the sacred texts--and teaches its followers to concentrate and meditate on reaching the true understanding of their buddha-nature. For a further discussion of Zen practice, see the Religious Life page.
Vajrayana largely takes over Mahayana's understanding of the cosmos, and its definition of the human problem. It differs primarily in its depiction of Cosmic Unity as the union of a duality, in the additional figures with which it populates the cosmos, and in its solution to the human problem.
Vajrayana emphasizes the nature of Mahayana's notion of the Buddha's Dharma Body, that the Buddha is Ultimate Reality. As Nagarjuna put it, samsara and nirvana are one and the same. Thus, Ultimate Reality is the union of samsara and nirvana; at once diametric opposites and the same thing. Drawing upon the tantric writings, Vajrayana often represents this notion of opposites as male and female. The union of these opposites is thus depicted in sexual intercourse. Human sexuality therefore becomes both a metaphor and a representation of the cosmos.
To represent this union, called yab-yum, buddhas and bodhisattvas have both male and female aspects--similar to the way Hinduism depicted Parvati as Shiva's female aspect. For example, the male bodhisattva Chenrezig has a female form called Tara who embodies the female aspects of compassion. Furthermore, both male and female bodhisattvas have two forms, peaceful and wrathful. Chenrezig's wrathful form is Mahakala, which protects his worshippers and meditators from harm by demons.
These two changes that Vajrayana emphasizes bring about further change in its solution to the human problem. While Vajrayana keeps the notion of bodhisattvas and compassion, it adds to it in important ways. Vajrayana is called the "Diamond Vehicle" to enlightenment because the hardness of the diamond suggests the enlightenment can be attained in a single lifetime. The way is hard, but with the proper help and practices it can be achieved. The first change is that Vajrayana monks work closely with a guru (a teacher) who guides them at every step of the path until they themselves become adept. The first thing the guru does with each novice is to connect him to a yidam, that is, a personal deity (usually a bodhisattva) with whom the novice will establish a life-long link and who will help guide and support the monk as he works towards enlightenment. Tara is often used as a yidam.
Another aspect of the "Diamond Vehicle's" solution to the human problem is the idea that to progress quickly towards enlightenment, the entire body needs to be used. Thus meditation is done with sound (mantras), with vision (mandalas), with hand gestures (mudras) and body positions. The adept may also use certain aspects of sexual practice, in imitation of cosmic unity, to enhance their wisdom and power.