Prajñā (Sanskrit) or paññā (Pali) has been translated as "wisdom," "understanding," "discernment," "cognitive acuity," or "know-how." In some sects of Buddhism, it especially refers to the wisdom that is based on the direct realization of the Four Noble Truths, impermanence, interdependent origination, non-self, emptiness, etc. Prajñā is the wisdom that is able to extinguish afflictions and bring about enlightenment.
In the Pali Canon
In the Pali Canon, paññā is defined in a variety of overlapping ways, frequently centering on concentrated insight into the three characteristics (impermanence, suffering, no-self) of all things and the Four Noble Truths.
- "And what is the faculty of discernment? There is the case where a monk, a disciple of the noble ones, is discerning, endowed with discernment of arising & passing away — noble, penetrating, leading to the right ending of stress. He discerns, as it is actually present, [the Four Noble Truths]: 'This is stress... This is the origination of stress... This is the cessation of stress... This is the path of practice leading to the cessation of stress.' This is called the faculty of discernment."
- "And what is the training in heightened discernment? There is the case where a monk discerns as it actually is that 'This is stress... This is the origination of stress... This is the cessation of stress... This is the path of practice leading to the cessation of stress.' This is called the training in heightened discernment."
In a subsequent discourse regarding the Threefold Training, the Buddha indicates that higher wisdom entails the application of concentration and insight to end "fermentations" (or "mental intoxicants"; Pali: āsava), effectively achieving arahantship:
- "And what is the training in heightened discernment? There is the case where a monk, through the ending of the mental fermentations, enters & remains in the fermentation-free awareness-release & discernment-release, having known & made them manifest for himself right in the here & now. This is called the training in heightened discernment."
- "And what, monks, is right view? Knowledge with regard to stress, knowledge with regard to the origination of stress, knowledge with regard to the stopping of stress, knowledge with regard to the way of practice leading to the stopping of stress: This, monks, is called right view.
- "And what is right resolve? Being resolved on renunciation, on freedom from ill will, on harmlessness: This is called right resolve."
From the Visuddhimagga
In to the fifth-century CE exegetic Visuddhimagga, Buddhaghosa states that the function of paññā is "to abolish the darkness of delusion" and that it is "manifested as non-delusion." Its proximate cause is concentration.
Buddhaghosa provides the analogy of a tree to discuss the development of paññā:
- The soil of the tree are the:
- The roots are:
- purification of virtue
- purification of consciousness.
- The trunk is made up of:
- purification of view
- purification by overcoming doubt
- purification by knowledge and vision of what is and is not the path
- purification by knowledge and vision of the way
- purification by knowledge and vision.
Buddhaghosa instructs that, to achieve paññā, one should first learn about the soil, then the roots and then the trunk.
From the Prajñā-pāramitā Sutras
The Prajñā-pāramitā Sutras, such as the Heart Sutra, describe prajñā as supreme, highest, incomparable, unequalled, and unsurpassed. It is spoken of as the principal means, by its enlightenment, of attaining nirvana, through its revelation of the true nature of all things.
The beginning of the Heart Sutra includes the phrase "...doing Prajñā..." indicating that prajñā is also an activity as well as an outcome, quality or state. As activity, prajñā can be described as "choiceless engagement" where "choiceless" means selflessly accepting outcomes as they develop while understanding interdependent co-existence and sunyata, followed by further engagement.
In the history of Zen Buddhism, the Sixth Patriarch Hui-neng (d. 713) emphasized the practice of prajñā in counterpoint to the quietistic and self-absorbed style of meditation that was then current. In so doing, he emphasized dynamic action and human involvement as essential to Zen practice.
As a Perfection
Three prajnas or mula prajñā
Norbu et al. (1999, 2001: pp. 136–137) render the 'mūla prajñā' (Sanskrit) where 'mula' may be set into English as 'root' (of a tree), thus:
- 'Study' (Sanskrit: shruta, Tibetan: thos + pa)
- 'Reflection' (Sanskrit: cinta, Tibetan: sam+ pa)
- 'Meditation' (Sanskrit: bhavana, Tibetan: sgom pa)
These three aspects are the mula prajñā of the sadhana of Prajñā-Pāramitā, the "paramita of wisdom". Hence, these three are related to, but distinct from, the Prajñāpāramitā that denotes a particular cycle of discourse in the Buddhist literature that relates to the doctrinal "field" (Sanskrit: kṣetra) of the second turning of the Dharmachakra.
Gyatrul (b.1924), in a purport to the work of Chagmé (Wylie: karma-chags-med, fl. 17th century), rendered into English by Wallace (Chagmé et al., 1998: pp. 35–36), conveying the importance of internalizing and integrating the doctrine by extending the metaphor, states:
...do not let your Dharma be like rice in a bowl, always remaining separate from the container. Rather, apply Dharma by means of hearing, thinking, and meditating. One of these alone is not enough. All three must be practiced. If you lack hearing and thinking, you are not in a good position to meditate effectively. Such meditation is like trying to climb a mountain without your hands. However much you learn of the Dharma, practice it with faith and compassion. Apply it to your own mind. 
In a commentary to Rangjung Dorje's Namshe Yeshe Gepa (Wylie: rnam shes ye shes ‘byed pa) by Khenchen Thrangu Rinpoche rendered into English by Peter Roberts (2001), the mulaprajna are discussed thus:
We shouldn’t believe in something just because the Buddha, or some great scholar or lama says so. We need a very clear and profound conviction that the Buddha’s teachings are correct and this is gained by using analysis and our own intelligence. Therefore, after our teacher has taught us the path, we should analyze and thoroughly contemplate the teachings, and so gain the second type of understanding, which arises from this contemplation.
This understanding based on listening and contemplation is not enough—this alone cannot transform our mind. This final transformation is accomplished by the practice of meditation.
- SN 48.10 (Thanissaro, 1997).
- AN 3:88 (Thanissaro, 1998b, which includes the ellipses used in this article's block quote; also see Nyanaponika & Bodhi, 1999, pp. 69-71).
- AN 3:89 (Thanissaro, 1998c; also see Nyanaponika & Bodhi, 1999, pp. 69-71). Also see Rhys Davids & Stede (1921-25), entry on "Āsava" (pp. 115-16) (retrieved 2007-06-22), which in part states: "Freedom from the 'Āsavas' constitutes Arahantship...."
- In MN 44 (Thanissaro, 1998a), Bhikkhuni Dhammadinnā – who the Buddha declared the foremost Dharma teacher amongst his nuns (see Sravaka) – states:
- "...[T]he noble eightfold path is included under the three aggregates [of virtue, concentration, & discernment]. Right speech, right action, & right livelihood come under the aggregate of virtue. Right effort, right mindfulness, & right concentration come under the aggregate of concentration. Right view & right resolve come under the aggregate of discernment."
- SN 45.8 (Thanissaro, 1996).
- Buddhaghosa & Ñāṇamoli (1999), p. 437.
- Buddhaghosa & Ñāṇamoli (1999), pp. 442-443.
- Norbu, Namkhai (author, compiler); Clemente, Adriano (translated from Tibetan into Italian, edited and annotated); Lukianowicz, Andy (translated from Italian into English) (1999, 2001). The Precious Vase: Instructions on the Base of Santi Maha Sangha. Second revised edition. Shang Shung Edizioni, pp.136-137.
- Source:  (accessed: Wednesday March 25, 2009)
- Chagmé, Karma (author, compiler); Gyatrul Rinpoche (commentary) & Wallace, B. Alan (translator) (1998). A Spacious Path to Freedom: Practical Instructions on the Union of Mahamudra and Atiyoga. Ithaca, New York, USA: Snow Lion Publications. ISBN 9781559390712; ISBN 1559390719, pp.35-36
- Rangjung Dorje (root text); Venerable Khenchen Thrangu Rinpoche (commentary); Peter Roberts (translator) (2001). Transcending Ego - Distinguishing Consciousness from Wisdom (Wylie: rnam shes ye shes ‘byed pa). Source:  (accessed: Wednesday April 1, 2009)
- Boowa Ñãnasampanno Bhikkhu. Wisdom Develops Samādhi. Retrieved 2009-01-17 from "What the Buddha taught" at http://www.what-buddha-taught.net/Books/Maha_Boowa_Wisdom_Develops_Samadhi.htm.
- Brahmavamso Bhikkhu. The Path to Bliss and Wisdom. Retrieved 2009-01-17 from "What the Buddha taught" at http://www.what-buddha-taught.net/Books8/Ajahn_Brahm-The_Path_to_Bliss_and_Wisdom.pdf.
- Buddhaghosa, Bhadantācariya and Bhikkhu Ñāṇamoli (trans.) (1999). The Path of Purification: Visuddhimagga. Seattle, WA: BPS Pariyatti Editions. ISBN 1-928706-00-2.
- Nyanaponika Thera and Bhikkhu Bodhi (trans. and ed.) (1999). Numerical Discourses of the Buddha: An Anthology of Suttas from the Anguttara Nikaya. Walnut Creek, CA: Altamira Press. ISBN 0-7425-0405-0.
- Rhys Davids, T.W. & William Stede (eds.) (1921-5). The Pali Text Society’s Pali–English Dictionary. Chipstead: Pali Text Society. A general on-line search engine for the PED is available at http://dsal.uchicago.edu/dictionaries/pali/.
- Thanissaro Bhikkhu. Jhanas, Concentration & Wisdom. Retrieved 2009-01-17 from "What the Buddha taught" at http://www.what-buddha-taught.net/Books/Bhikkhu_Thanissaro_Jhanas_Concentration_Wisdom.htm.
- Thanissaro Bhikkhu (trans.) (1996). Magga-vibhanga Sutta: An Analysis of the Path (SN 45.8). Retrieved 2007-06-22 from "Access to Insight" at http://www.accesstoinsight.org/tipitaka/sn/sn45/sn45.008.than.html.
- Thanissaro Bhikkhu (trans.) (1997). Indriya-vibhanga Sutta: Analysis of the Mental Faculties (SN 48.10). Retrieved 2007-06-22 from "Access to Insight" at http://www.accesstoinsight.org/tipitaka/sn/sn48/sn48.010.than.html.
- Thanissaro Bhikkhu (trans.) (1998a). Culavedalla Sutta: The Shorter Set of Questions-and-Answers (MN 44). Retrieved 2007-06-22 from "Access to Insight" at http://www.accesstoinsight.org/tipitaka/mn/mn.044.than.html.
- Thanissaro Bhikkhu (trans.) (1998b). Sikkha Sutta: Trainings (1) (AN 3:38). Retrieved 2007-06-22 from "Access to Insight" at http://www.accesstoinsight.org/tipitaka/an/an03/an03.088.than.html.
- Thanissaro Bhikkhu (trans.) (1998c). Sikkha Sutta: Trainings (2) (AN 3:39). Retrieved 2007-06-22 from "Access to Insight" at http://www.accesstoinsight.org/tipitaka/an/an03/an03.089.than.html.