This message is for relative beginners to Buddhism. It may be insufficiently sophisticated for the tastes of advanced practitioners, seasoned scholars and self-styled lobsters. It is also long, so you may wish to print it out and read it at your leisure.
Buddhism comes in a bewildering variety of schools and traditions, and a necomer can spend quite some time being lost in apparently meaningless detail. Even after thirty years of studying Buddhism as an academic and practising in several different traditions, I still find myself overwhelmed by the complexity of it all and have long since resigned myself to having a very superficial understanding of most of Buddhism and an only slightly less superficial understanding of a few specific traditions. So, since my understanding is superficial, it may be of some use to a few others who are also just beginning to scratch the surface.
It is helpful to think of Buddhism by picturing a very large and old tree. Such a tree usually has a single trunk, a number of main branches rising out of the trunk, some limbs on each branch, some twigs on each limb and some leaves on each twig. Beneath the surface of the earth is a root system that, like the part above the ground, branches into ever smaller units.
In imagining such a tree, think first of the single trunk that arises out of the roots and that supports all the many branches, limbs and twigs. This trunk is the action of going for refuge. It is the one thing that every Buddhist does, and it is the most important aspect of any Buddhist's study and practice. Every doctrine within Buddhism, every school and every practice can be seen as a particular outgrowth of this one essential action, which a Buddhist repeats again and again, namely, the action of going for refuge. In Pali this action is called sarana-gamana. Gamana means going. Sarana means shelter, support, help or guidance. Going for refuge to something means going to it for help and guidance and support. Almost invariably, it is something that one first does as a result of some crisis in one's life, some bit of unwelcome reality that one just cannot deal adequately with on one's own. So one turns to something outside oneself for help.
What makes a Buddhist a Buddhist is not just the fact of going for refuge. Most people go for refuge to something or another: acquaintances, alcohol, their careers, drugs, education, entertainment, experts, family, physical fitness clubs, psychiatrists, religion, sexual conquests, study, support groups, travel, or even the zoo. What makes a Buddhist a Buddhist is that he or she goes for refuge to the Buddha, the Dharma and the Sangha.
The three principal roots of the tree, therefore, are the Buddha, the Dharma and the Sangha. But there is not any one single meaning to any of these words. Each of them has many meanings to a Buddhist, so we can imagine each of the three main roots in the root system sending out branches. To describe each main root in detail is not necessary just now. Let's just sketch out each one briefly.
The central root is the Dharma. This word has several meanings. The most important meaning in a Buddhist context is Nirvana, which is seen by all Buddhists as the greatest possible good. Nirvana means the eradication (uprooting) of the root causes of all dissatisfaction. All Buddhists are striving for that final elimination of dissatisfaction. So that is the principal meaning of dharma. But the word Dharma also means that which helps one to achieve that final goal of Nirvana. What helps one to achieve that goal is a positive and healthy mentality; a single word for that is the word "virtue". So a secondary meaning of the word "dharma" is "virtue" in the sense of good character. But "dharma" also means that which helps one acquire virtue. So a tertiary meaning of "dharma" is a teaching. Any teachings that help one achieve Nirvana can be considered dharma, but usually Buddhists take refuge especially in the teachings preserved in the Sutras (recorded sermons and conversations of the Buddha and his most trusted male and female disciples) and in the Vinaya (the disciplinary code for monks and nuns, people who renounced the household life in order to dedicate all their time and energy to working for Dharma).
The other two main roots are the Buddha and the Sangha. There are several different views about what exactly the nature of a Buddha is, but everyone agrees that there have been many Buddhas throughout history and that the most recent was Siddhartha Gautama (or in Pali, Siddhattha Gotama), also know as the silent sage (muni) of the Sakiya (Sanskrit, Shakya) people; the Sakiyas were a tribal people, probably racially and certainly culturally distinct from the Aryans. So when Siddhartha Gautama went into the cities of Benares and so forth in the Ganges valley, he probably looked and talked like a foreigner and acted in ways that people found a bit odd. There are several texts in which people comment on the fact that he is a barbarian and therefore unworthy of the kind of respect that one normally shows to civilized people. But, despite his foreign origins and a certain amount of prejudice against him, the Buddha managed to win the the respect of quite a few important people, including several Kings and military leaders and wealthy merchants and learned scholars of his day. All of these people respected him as a teacher and guide. So when one goes for refuge to the Buddha, one honours him as the best teacher of human beings and gods, the finest man to walk on two feet. In other words, he is a Buddhist's principal role model.
The word "Sangha"means a group or community. The Sangha to which a Buddhist goes for refuge is the ariya-sangha, which means the Noble Community of people who have attained insight and virtue and who have either attained or come very close to attaining Nirvana. It is important to realize that not all members of the Noble Community are monks or nuns, and that not all monks or nuns are members of the Noble Community. So a Buddhist does not go for refuge to the community of monks or nuns or even to the community of people who declare themselves to be Buddhists, but to the community of all excellent people everywhere whose insight and purity of character is significantly superior to that of the average human being. The word "Sangha" can also refer to other communities, such as the community of monks (bhikkhu-sangha), the community of nuns (bhikkhuni-sangha), the community of householders who support the monks and nuns (upasaka-sangha) and to the entire community of people who heard the Buddha and formally went to him for refuge (savaka-sangha). Sometimes some Buddhists find it convenient to think of the community of Buddhists as a whole as a kind of concrete symbol of the much more abstract notion of the Noble Sangha of excellent people to which they go for refuge.
These three roots support the trunk of the tree, which is the single act of going for refuge, the essence of Buddhism as an organized religion. There are many different ways of going for refuge. Ultimately, you could say that there are as many ways as there have been individual Buddhists throught the history of Buddhism, because ultimately going for refuge is an individual decision that each individual has to figure out how to put into practice is his or her life. We can think of the individual Buddhists as the leaves on the tree. Leaves grow on twigs attached to limbs that grow out of branches out of the main trunk. So now let's look at the main branches.
The branches of the tree can be seen as being based mostly on collections of books that are believed to contain teachings of the Buddha and his most trusted disciples (and disciples of his disciples down through the ages). One main branch was known as the Savaka(Sanskrit Shravaka) branch. These people chose to base their practice on doctrines that were believed by everyone to be the public teachings of the Buddha to his monks and lay disciples. At one time there were many limbs of this Savaka branch, but only one of them has lived to modern times. That is the limb known as Theravada, which means the teachings of the elders. An elder is a monk who has been ordained for a minimum of ten years and who is acknowledged to have attained insight. Officially, the Theravada school is based only on what has been transmitted by these elders down through the ages. This body of teachings have been preserved in a pali, a word that means a straight line. The English word "canon" comes from a Greek word meaning a straight line or a straight-edge, so early translators of Buddhist texts translated the word "pali" as "canon" and reduntantly named the works of this school the Pali Canon. The language in which that canon is preserved is called the Pali language. While many Theravadin teachers admire and study and refer to individuals and writings that are not in the Pali canon, the framework within which all teachings are interpreted is provided by the Pali canon. The Theravada school exists nowadays in Sri Lanka (formerly called Ceylon), Myanmar (formerly called Burma), Thailand (formerly called Siam), Laos, Cambodia and parts of Vietnam.
A second branch of the tree is one that itself immediately branches into a lot of different limbs. What all the limbs on this branch have in common is that they accept the authority of texts that the Shravaka branch explicitly rejected as being the teachings of the historical Buddha. This branch can be called the Mahayanabranch. The number of Mahayana texts is so large that no one can hope to read them all within a single lifetime, so usually Mahayana Buddhists specialize by focusing on just a few texts or sometimes only one text. The Zen school, for example, is said to have originally been based on the transmission of one text, called the Lankavatara Sutra (the full title of which means the introduction of the true dharma into Sri Lanka, a country that had both Theravada and Mahayana branches of Buddhism). The so-called Pure Land schools of Buddhism were based on texts describing beautiful realms into which one could be reborn in order to pursue dharma more easily than is possible in our difficult world. There are several twigs growing out of a limb known as Lotus Buddhism, which is based on the White Lotus of the True Dharma, a sutra that attempts to reconcile all the branches of Buddhism into one; one of the best known twigs on this limb is Nichiren Buddhism, out of which has grown a twiglet known as Soka Gakkai International, which has made quite an impact in the United States (and throughout the world) through its energetic prosyletizing. Quite a lot of these limbs interwine and grown together in various ways, rather like the tangled mess of a banyan tree or a briar patch.
Mahayana Buddhism once thrived in China, Korea, Japan, Vietnam and Indonesia. It is now very weak in China and has been for most of this century. It has completely disappeared from Indonesia, which is now a Muslim country. Only about one-third of the population of Korea is still Buddhist; the majority of Koreans are now Christians. In Vietnam, there is now one single form of Buddhism, which resulted from combining Theravada and Mahayana into a single school. It has been considerably weakened by all the wars and revolutions in that country, and by the recent passion for modernization. In Japan interest in Buddhism is rapidly declining in most sectors of the population and is being displaced by hundreds of so-called New Religions (some of which pay at least a token respect to something vaguely Buddhist in character). It is quite possible that Mahayana Buddhism could disappear from Asia within the next twenty-five years. Sadly, this once-strong and healthy branch is now rotting and may collapse of its own weight.
The third branch of the tree is the Vajrabranch. (It might be more accurate to say this this is a limb growing out of Mahayana, but it has become distinctive enough to be regarded now as a separate branch unto itself.) The word vajra means a clap of thunder. It also means a diamond. The texts upon which this branch is based are known as tantras, so this form of Buddhism is also called Tantric Buddhism. Tantras are usually written in a kind of code so that their meaning is not apparent to someone who has not been initiated into them. Unlike other forms of Buddhism, tantric Buddhism is therefore esoteric. One cannot study it or practice it without a special teacher, who confers special baptisms (abhisheka) that give people a special grace or power by which they can put the teachings into practice. Tantric Buddhism is the main form of Buddhism in Tibet and Mongolia (which got it from Tibet). There are also tantric forms of Buddhism in China, which in turn transmitted tantric forms to Vietnam, Korea and Japan. Even forms of Buddhism that are not strictly speaking purely tantric (if there is such a thing) have been influenced by tantric thinking and some tantric practices. So, for example, Vietnamese Buddhism is now a very interesting and healthy synthesis of Theravada, several limbs of Mahayana such as Zen and Pure Land and scholasticism, and tantric Buddhism. Korean Buddhism is now a synthesis of Zen, Pure Land and various scholastic forms of Mahayana Buddhism, with elements of tantra appearing here and there.
The roots, the single trunk and the branches have now all been explained. All that remains is to discuss what the whole tree is made of. It is made of two ingedients, wood and sap. The wood, which is the substantial core of all Buddhism, is Wisdom. The sap, which keeps the tree alive by transmitting nourishment from the deep roots to the individual leaves, is Compassion. Without the sap of compassion running throughout the tree, the whole tree would quickly die. Without the wood of wisdom, the sap would have no means of flowing and would quickly evaporate. So neither can be seen as more essential than the other. The two together are the life force of the tree of dharma.
If I may, I would like to end by recommending two books, one that is full of information, and the other that has tips about practice. Both are easily ordered through your local bookstore or directly from their publisher, Windhorse Publications.
Andrew Skilton. _A Concise History of Buddhism_. Windhorse Publications, 1994. [Offers an intelligent and readable thumbnails sketch of the different branches of Buddhism and their spread into different geographical areas within India and then outside India]
Paramananda, _Changing Your Mind_. Windhorse Publications, 1997. [A very readable, informative and practical guide to traditional Buddhist meditational practices, written especially for modern Westerners.]
The address of Windhorse Publications in England is Unit 1-316 The Custard Factory Gibb Street Birmingham B9 4AA
In America the address of the main distributor is: 14 Heartwood Circle Newmarket, NH 03957