In modern terms, we might call the Buddha's Eightfold Path an eight-part program toward realizing enlightenment and liberating ourselves from dukkha (suffering; stress). Right Concentration (in Pali, Samma Samadhi) is the eighth part of the path.
It's important to understand that the Eightfold Path is not an eight-step program. In other words, the eight parts of the path are not steps to be mastered one at a time. They are to be practiced all together, and each part of the path supports every other part of the path.
Three parts of the path -- Right Effort, Right Mindfulness, and Right Concentration -- are associated with mental discipline. These three aspects of the path might sound somewhat alike, especially mindfulness and concentration. Very basically,
- Right Effort involves cultivating what is wholesome and purifying oneself of what is unwholesome.
- Right Mindfulness is being fully present and aware of one's body, senses, thoughts, and surroundings. It is the opposite of being lost in daydreams.
- Right Concentration is focusing all of one's mental faculties onto one physical or mental object and practicing the Four Absorptions, also called the Four Dhyanas (Sanskrit) or Four Jhanas (Pali).
The Role of Meditation
Right Concentration is most often associated with meditation. In Sanskrit and Pali, the word for meditation is bhavana, which means "mental culture." Buddhist bhavana is not a relaxation practice, nor is it about having visions or out-of-body experiences. As explained by the Theravadin scholar Walpola Rahula,
The Buddhist bhavana, properly speaking, is mental culture in the full sense of the term. It aims at cleansing the mind of impurities and disturbances, such as lustful desires, hatred, ill-will, indolence, worries and restlessness, sceptical doubts, and cultivating such qualities as concentration, awareness, intelligence, will, energy, the analytical faculty, confidence, joy, tranquility, leading finally to the attainment of highest wisdom which sees the nature of things as they are, and realizes the Ultimate Truth, Nirvana." [Walpola Rahula, What the Buddha Taught (Grove Press, 1974), p. 68]
Bhavana really involves all parts of the Eightfold Path, but the particular role of Right Concentration has to do with the dhyanas.
The Four Dhyanas (or Jhanas)
The Four Dhyanas, Jhanas, or Absorptions are the means to experience directly the wisdom of the Buddha's teachings. In particular, through Right Concentration we can be freed from the delusion of a separate self.
In the first dhyana, passions, desires and unwholesome thoughts (see akusala) are released. A person dwelling in the first dhyana feels rapture and a deep sense of well-being.
In the second dhyana, intellectual activity fades and is replaced by tranquility and one-pointedness of mind. The rapture and sense of well-being of the first dhyana are still present.
In the third dhyana, the rapture fades and is replaced by equanimity (upekkha) and great clarity.
In the fourth dhyana, all sensation ceases and only mindful equanimity remains.
In some schools of Buddhism, the fourth dhyana is described as pure experience with no "experiencer." Through this direct experience, one perceives the individual, separate self to be an illusion.
The Four Immaterial States
In Theravada and probably some other schools of Buddhism, after the Four Dhyanas come the Four Immaterial States. This practice is understood as going beyond mental discipline and actually refining the objects of concentration themselves. The purpose of this practice is to eliminate all visualizations and other sensations that may remain after the dhyanas.
In the four Immaterial States, one first refines infinite space, then infinite consciousness, then non-materiality, then neither perception-nor-not-perception. The work at this level is enormously subtle.
So is this enlightenment? Not quite yet, some teachers say. In other schools, it is understood that enlightenment is already present, and Right Concentration is a means for realizing this.