The Middle Length Discourses of the Buddha - Bhikkhu Nanamoli [17]
THE FOUR PLANES OF LIBERATION
The practice of the Buddhist path evolves in two distinct stages, a mundane (lokiya) or preparatory stage and a supramundane (lokuttara) or consummate stage. The mundane path is developed when the disciple undertakes the gradual training in virtue, concentration, and wisdom. This reaches its peak in the practice of insight meditation, which deepens direct experience of the three characteristics of existence. When the practitioner’s faculties have arrived at an adequate degree of maturity, the mundane path gives birth to the supramundane path, so called because it leads directly and infallibly out of (uttara) the world (loka) comprising the three realms of existence to the attainment of “the deathless element,” Nibbāna.
Progress along the supramundane path is marked by four major breakthroughs, each of which ushers the disciple through two subordinate phases called the path (magga) and its fruit (phala). The phase of path has the special function of eliminating a determinate number of defilements to which it is directly opposed, the mental impediments that hold us in bondage to the round of rebirths. When the work of the path has been completed, the disciple realises its corresponding fruit, the degree of liberation made accessible by that particular path. The canonical formula of homage to the Sangha refers obliquely to these four planes of liberation—each with its phase of path and fruit—when it extols the Blessed One’s community of noble disciples as comprising “the four pairs of persons, the eight types of individuals” (MN 7.7). These four pairs are obtained by taking, for each stage, the one who has entered upon the way to realisation of the fruit and the one who has attained the fruit.
In the suttas the Buddha highlights the specific characteristics of each supramundane stage in two ways: by mentioning the defilements that are abandoned on each plane and the consequences its attainment bears on the process of rebirth (see, e.g., MN 6.11–13, 19; MN 22.42–45, etc.). He handles the elimination of the defilements by classifying these into a tenfold group called the ten fetters (saṁyojana). The disciple enters upon the first supramundane path either as a Dhamma-follower (dhammānusārin) or as a faith-follower (saddhānusārin); the former is one in whom wisdom is the dominant faculty, the latter one who progresses by the impetus of faith. This path, the path of stream-entry, has the task of eradicating the grossest three fetters: identity view, i.e., the view of a self among the five aggregates; doubt in the Buddha and his teaching; and adherence to external rules and observances, either ritualistic or ascetic, in the belief that they can bring purification. When the disciple realises the fruit of this path he becomes a stream-enterer (sotāpanna), who has entered the “stream” of the Noble Eightfold Path that will carry him irreversibly to Nibbāna. The stream-enterer is bound to reach final liberation in a maximum of seven more births, which all occur either in the human world or in the heavenly realms.
The second supramundane path attenuates to a still greater degree the root defilements of lust, hatred, and delusion, though without yet eradicating them. On realising the fruit of this path the disciple becomes a once-returner (sakadāgāmin), who is due to return to this world (i.e., the sense-sphere realm) only one more time and then make an end of suffering. The third path eradicates the next two fetters, sensual desire