Most people have heard that the Buddha was enlightened, and that Buddhists seek enlightenment. But what does that mean, exactly? What is enlightenment, and how do you know when you've "got" it?
To begin, it's important to understand that "enlightenment" is an English word that can mean several things. For example, in the West, the Age of Enlightenment was a philosophical movement of the 17th and 18th centuries that promoted science and reason over myth and superstition. In western culture, then, the word "enlightenment" is often associated with intellect and knowledge. But Buddhist enlightenment is something else.
Enlightenment and Satori
To add to the confusion, the word "enlightenment" has been used to translate several Asian words that don't mean precisely the same thing. For example, several decades ago English speakers were introduced to Buddhism through the writing of D.T. Suzuki (1870-1966), a Japanese scholar who had lived for a time as a Rinzai Zen monk. Suzuki used "enlightenment" to translate the Japanese word satori, derived from the verb satoru, "to know." This translation was not without justification.
But in usage, satori usually refers to an experience of insight into the true nature of reality. It has been compared to the experience of opening a door, but to open a door is still a separation from what's inside the door. Partly through Suzuki's influence, the idea of spiritual enlightenment as a sudden, blissful, transformative experience became embedded in western culture. However,that's a misleading idea.
Enlightenment and Bodhi (Theravada)
Bodhi is a Sanskrit and Pali word that means "awakening," and it also is often translated as "enlightenment."
In Theravada Buddhism, bodhi is associated with the perfection of insight into the Four Noble Truths, which brings about the cessation of dukkha (suffering; stress; dissatisfaction). The person who has perfected this insight and abandoned all defilements is an arhat, one who is liberated from the cycle of samsara. While alive he enters a sort of conditional nirvana, and at death he enjoys the peace of complete nirvana.
"Then, monks, this is the criterion whereby a monk, apart from faith, apart from persuasion, apart from inclination, apart from rational speculation, apart from delight in views and theories, could affirm the attainment of enlightenment: 'Birth is destroyed, the holy life has been accomplished, what was to be done is done, there is no further living in this world.'"
Enlightenment and Bodhi (Mahayana)
Why is this important? Most of us perceive the things and beings around us as distinctive and permanent. But this view is a projection. Instead, the phenomenal world is an ever-changing nexus of causes and conditions (see also Dependent Origination). Things and beings, empty of self-essence, are neither real nor not real (see also "The Two Truths"). Thoroughly perceiving sunyata dissolves the fetters of self-clinging that cause our unhappiness.
In Mahayana Buddhism, the ideal of practice is the bodhisattva, the enlightened being who remains in the phenomenal world to bring all beings to enlightenment. The bodhisattva ideal is more than altruism; it reflects the reality that none of us are separate.
However, although D.T. Suzuki and some of the first Zen teachers in the West explained enlightenment as an experience, most Zen teachers and Zen texts will tell you that enlightenment is not an experience. Not even satori is enlightenment itself.
Enlightenment and Buddha Nature
According to Zen legend, when the Buddha realized enlightenment he said, "Isn't it remarkable! All beings are already enlightened!" This "already enlightened" state is Buddha Nature. In Mahayana Buddhism, Buddha Nature is the inherent Buddhahood of all beings. Because all beings are already Buddha, the task is not to attain enlightenment but to reveal it.
The Chinese master Huineng (638-713), the Sixth Patriarch of Ch'an (Zen), compared Buddhahood to a moon obscured by clouds. The clouds represent ignorance and defilements. When these are dropped away the moon, already present, is revealed.
What happened to the sudden, blissful, transformative experience? Such an experience is not, by itself, enlightenment. Such an experience may -- or may not -- accompany a deep insight. But a blissful spiritual experience not grounded in practice of the Eightfold Path will not likely be transformative.
Further, this practice is for a lifetime. It is not something you can cross off your "to do" list when the goal is reached. Zen teacher Barry Magid said of Master Hakuin,
"Post-satori practice for Hakuin meant finally ceasing to be preoccupied with his own personal condition and attainment and to devote himself and his practice to helping and teaching others. Finally, at long last, he realized that true enlightenment is a matter of endless practice and compassionate functioning, not something that occurs once and for all in one great moment on the cushion." [From the upcoming book Nothing Is Hidden.]
In some traditions you might hear that an enlightened being gains omniscience and supernatural powers. Other traditions teach that while the "enlightened being" may have remarkable attributes, this being neither is nor is not the conditional being who eats and shaves and wears socks.
Shunryu Suzuki (1904-1971) said of enlightenment,
"It is kind of mystery that for people who have no experience of enlightenment, enlightenment is something wonderful. But if they attain it, it is nothing. But yet it is not nothing.Â Do you understand?Â For a mother with children, having children is nothing special. That is zazen. So, if you continue this practice, more and more you will acquire something - nothing special, but nevertheless something. You may say "universal nature" or "Buddha nature" or "enlightenment." You may call is by many names, but for the person who has it, it is nothing, and it is something."
But how do you know when you "have" it? Enlightenment is not a quality that can be possessed. And individuals are notoriously bad judges of their own degree of awakening. The only way to test one's insight is to present it to a dharma teacher. And don't be dismayed if what you think you've "gotten" falls apart under the teacher's scrutiny. When the insight is genuine, it won't fall apart.