II.51 बाह्याभ्यन्तरबिषयाक्षेपी चतुर्थः

bāhyābhyantara-viṣayākṣepī caturthaḥ
bāhya-abhyantara-viṣaya-ākṣepī caturthaḥ

“Beyond the realm of external/internal [is] the fourth.”

Catur is the cardinal number four and caturtha is its ordinal: “fourth.” What is Patañjali describing here as being fourth? A fourth kind of movement of breath? A fourth method of practicing with the breath? A fourth experience of breath?

Classical commentators, beginning with the fifth-century Vyāsa, have asserted that this sūtra refers to an advanced technique of prāṇāyāma in which breath is entirely suspended. Edwin Bryant relates the story (from the Bhāgavata Purāṇa) of Dhruva, who is said to have suspended his breath for fourteen or fifteen days at a time, and explains that such stories are common in the lore of ancient India.

Notwithstanding, B.K.S. Iyengar says “the fourth” is something other than methodology. It is not a technique at all. It is a state beyond perception of external or internal, beyond the observation of  time, place, and number (as described in II.50). It is not something one does. It is a pause, not just of the breath, but of consciousness. A fourth part, perhaps, of awareness itself.

It is useful to turn to the Māṇḍukya Upaniṣad for guidance on the significance of caturtha. That short and beautiful text identifies the sacred syllable OM as representing all that is–past, present and future, and whatever else is beyond past, present and future. It further says that OM has four parts, indicated by the letters A-U-M (the vowel sound O is a dipthong and can be considered a combination of  A and U). The first part, expressed by the vowel A, represents waking. The second, expressed by U, dreaming. The third, associated with the nasal sound M, with deep, dreamless sleep. The fourth part, caturtha, has no letter. It is beyond description–ungraspable, unnameable, the essence:

Not having inward cognition not external cognition nor having both … They (the wise) consider the fourth to be unseen, indistinguishable, ungraspable, possessing no sign, unthinkable, unnameable–the essence of the knowledge of one Self, the cessation of all phenomenon, tranquil, auspicious, non-duality… —Māṇḍūkya Upaniṣad, verse 7, translation by Vyaas Houston

The fourth part approaches the territory of what cannot be articulated. And yet, the fourth part is there, in every OM, between things–as it were–like the air (see Matthew Remski, below).

In today’s sūtra, Patañjali says that the fourth part is bāhya-abhyantara-viṣaya-ākṣepī, “beyond the region of external/internal.”  Ākṣepi (which I have translated as “beyond”) is derived from ā-, an intensifying prefix, and kṣip, “to cast”; it is literally “having thrown down” or “having cast over.” A thing that is ākṣepi eclipses, surpasses, overlays (perhaps underlies). The word reminds one of the opening of Genesis, where the spirit hovers over the waters. Ākṣepi suggests all this, including the idea that the fourth part “throws down” our ordinary perceptions–jumbles, jangles our assumptions. Tranquil, auspicious, non-dual–as the Māṇḍukya says–the fourth part surprises us, restores us.

Only by the the form, the pattern,
Can words or music reach
The stillness, as a Chinese jar still
Moves perpetually in its stillness,
Not the stillness of the violin, while the note lasts,
Not that only, but the co-existence,
Or say that the end precedes the beginning,
And the end and the beginning were always there
Before the beginning and after the end.
And all is always now. Words strain,
Crack and sometimes break, under the burden,
under the tension, slip, slide, perish,
Decay with imprecision, will not sty in place,
Will not stay still. –T. S Eliot, Four Quartets


“The fourth type of prāṇāyāma goes beyond the regulation or modulation of breath flow and retention, transcending the methodology given in the previous sūtra. … A state of pause is experienced, in both the breath and the mind. From this springs forth a new awakening.” –B.K.S. Iyengar, Light on the Yoga Sūtras of Patañjali, commentary on II.51

“The breath is a bridge between self and not-self. Crossing it with awareness will soften the boundary. It is impossible to say when air becomes you, but it does: feeding the metabolism behind all movement, tissue formation, and tissue repair. Simultaneously, air is ‘externally’ ubiquitous.  We wade through it as through water. We are pervaded by the source of our life: this breath-to-be. We think that the space between us is a mark of our separation, when in fact it contains what allows us to live. We are conjoined by the invisible source of life.” –Matthew Remski, Threads of Yoga, pp. 119-120

“The fourth, caturthaḥ, type of prāṇāyāma, says Vyāsa, refers to the total suppression of breath. and so, like the kumbhaka mentioned previously, also involves the cessation of inhalation and exhalation. … The commentators are not overly helpful in clarifying the difference between the third type of prāṇāyāma, kumbhaka, and the fourth type, caturthaḥ. As is the case with so much of the yoga sūtras, it is clear these are techniques to be experienced by practice rather than understood intellectually.” –Edwin Bryant, The Yoga Sūtras of Patañjali, commentary on II.51

“This generally misunderstood aphorism could possibly be a reference to a special phenomenon occurring in the enstatic state [samādhi], where breathing can become so reduced and shallow that it cannot be detected by unaided observation. … This fourth mode of breathing is thus, properly speaking, not a form of voluntary breath control at all but is simply the physiological correlate of an extraordinary state of consciousness.” –Georg Feuerstein, The Yoga-Sūtra of Patañjali, commentary on II.51

• How does attention to the breath affect your body, mind, emotions?
• How does breath connect you to others? In movement? In stillness?
• What might it mean that “the end precedes the beginning”?


adjective in compound

exterior (from bahis, “outside”)


adjective in compound

interior (from abhi-, “to,” + antar, “inner, within”)


masculine noun in compound

realm, sphere, scope; object (from viṣ, “to act”)


masculine adjective, 1st case singular

overshadowing, eclipsing (from ā-, prefix that intensifies meaning, + kṣip, “to cast”; ākṣip = “to throw down”)


masculine noun, 1st case singular

fourth (from catur, “four”)

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