Āyatana (Pāli; Sanskrit: आयतन) is a Buddhist term that has been translated as "sense base", "sense-media" or "sense sphere". In Buddhism, there are six internal sense bases (Pali: ajjhattikāni āyatanāni; also known as, "organs", "gates", "doors", "powers" or "roots") and six external sense bases (bāhirāni āyatanāni or "sense objects"; also known as vishaya or "domains").
Buddhism and other Indian epistemologies identify six "senses" as opposed to the Western identification of five. In Buddhism, "mind" denotes an internal sense organ which interacts with sense objects that include sense impressions, feelings, perceptions and volition.
In the Four Noble Truths, the Buddha identifies that the origin of suffering (Pali, Skt.: dukkha) is craving (Pali: taṇhā; Skt.: tṛṣṇā). In the chain of Dependent Origination, the Buddha identifies that craving arises from sensations that result from contact at the six sense bases (see Figure 2 below). Therefore, to overcome craving and its resultant suffering, one should develop restraint of and insight into the sense bases.
In "The Vipers" discourse (Asivisa Sutta, SN 35.197), the Buddha likens the internal sense bases to an "empty village" and the external sense bases to "village-plundering bandits." Using this metaphor, the Buddha characterizes the "empty" sense organs as being "attacked by agreeable & disagreeable" sense objects.
Elsewhere in the same collection of discourses (SN 35.191), the Buddha's Great Disciple Sariputta clarifies that the actual suffering associated with sense organs and sense objects is not inherent to these sense bases but is due to the "fetters" (here identified as "desire and lust") that arise when there is contact between a sense organ and sense object.
In the "Fire Sermon" (Adittapariyaya Sutta, SN 35.28), delivered several months after the Buddha's awakening, the Buddha describes all sense bases and related mental processes in the following manner:
The Buddha taught that, in order to escape the dangers of the sense bases, one must be able to apprehend the sense bases without defilement. In "Abandoning the Fetters" (SN 35.54), the Buddha states that one abandons the fetters "when one knows and sees ... as impermanent" (Pali: anicca) the six sense organs, objects, sense-consciousness, contact and sensations. Similarly, in "Uprooting the Fetters" (SN 35.55), the Buddha states that one uproots the fetters "when one knows and sees ... as nonself" (anatta) the aforementioned five sextets.
To foster this type of penetrative knowing and seeing and the resultant release from suffering, in the Satipatthana Sutta (MN 10) the Buddha instructs monks to meditate on the sense bases and the dependently arising fetters as follows:
When the Buddha speaks of "understanding" the eye, ear, nose, tongue and body, what is meant?
According to the first-century CE Sinhalese meditation manual, Vimuttimagga, the sense organs can be understood in terms of the object sensed, the consciousness aroused, the underlying "sensory matter," and an associated primary or derived element that is present "in excess." These characteristics are summarized in the table below.
The compendious fifth-century CE Visuddhimagga provides similar descriptors, such as "the size of a mere louse's head" for the location of the eye's "sensitivity" (Pali: pasāda; also known as, "sentient organ, sense agency, sensitive surface"), and "in the place shaped like a goat's hoof" regarding the nose sensitivity (Vsm. XIV, 47–52). In addition, the Visuddhimagga describes the sense organs in terms of the following four factors:
In regards to the sixth internal sense base of mind (mano), Pali subcommentaries (attributed to Dhammapāla Thera) distinguish between consciousness arising from the five physical sense bases and that arising from the primarily post-canonical notion of a "life-continuum" or "unconscious mind" (bhavaṅga-mana):
In the fifth-century CE exegetical Visuddhimagga, Buddhaghosa identifies knowing about the sense bases as part of the "soil" of liberating wisdom. Other components of this "soil" include the aggregates, the faculties, the Four Noble Truths and Dependent Origination.