SN 35.93: Dvaya Sutta
Translated by Bhikkhu Ñananandahttp://www.accesstoinsight.org/lib/auth ... passage-21
"Owing to a dyad, monks, consciousness comes into being. And how, monks, does consciousness come into being owing to a dyad?
"Owing to the eye and forms arises eye-consciousness. The eye is impermanent, changing, 'becoming-otherwise.' Forms are impermanent, changing, 'becoming-otherwise.' Thus this dyad is fleeting and transient; impermanent, changing and 'becoming-otherwise.' That cause, that condition, that gives rise to eye-consciousness — that also is impermanent, changing, becoming-otherwise.' And how, monks, could eye consciousness, having arisen dependent on an impermanent condition, become permanent? Now the coming-together, the falling together, the meeting-together, of these three things: this, monk, is called 'eye-contact.' Eye-contact, too, is impermanent, changing, 'becoming-otherwise.' And how, monks, could eye-contact, having arisen dependent on an impermanent condition, become permanent? Contacted, monks, one feels. Contacted, one intends. Contacted, one perceives. Thus these states also are fleeting and transient; impermanent, changing, 'becoming-otherwise.'
"Owing to the ear and sounds arises ear-consciousness. The ear is impermanent...
"Owing to the nose and scents arises nose-consciousness. The nose is impermanent...
"Owing to the tongue and savors arises tongue-consciousness...The tongue is impermanent.
"Owing to the body and tangibles arises body-consciousness. The body is impermanent...
"Owing to the mind and ideas arises mind-consciousness. The mind is impermanent...contacted, monks, one feels. Contacted, one intends. Contacted, one perceives. Thus these states also are fleeting and transient; impermanent, changing, 'becoming-otherwise.'
"Thus, monks, consciousness comes into being owing to a dyad."Note
 The doctrinal importance of this 'dyad' may well be gauged by the Buddha's declaration with reference to it in the preceding sutta (XXV. 92.): "Whoever, monks, should say — 'Rejecting this dyad, I will proclaim another dyad' — it would be mere talk on his part, and when questioned, he would not make good his boast, and further, would come to an ill pass. Why so? Because, monks, it would be beyond his scope." http://awake.kiev.ua/dhamma/tipitaka/2S ... ggo-e.html
Now the following verse of the Dhp.(v. 384) has a reference to dyads:
'yadaa dvayesu dhammesu — paaraguu hoti braahmano athassa sabbe sa.myogaa — attha.m gacchanti jaanato'
'When the arahant becomes 'one who has gone beyond' (paaraguu) with regard to the things forming the dyads, then all fetters of the knowing-one pass away.'http://www.accesstoinsight.org/tipitaka ... .budd.html
The commentary (Dhp. A.) takes the dyads to mean 'calm-and-insight' ('dvayesuuti dvidhaa .thitesu samatha-vipassanaa dhammesu...'). However, on the strength of the Buddha's declaration cited above, it is more reasonable to interpret it in the light of the present sutta. The word 'paaraguu' (lit. 'crossed to the further shore') in the verse, may be taken as an illusion to the 'Ocean-sutta' at S. IV 157. [http://www.accesstoinsight.org/lib/authors/nanananda/wheel183.html#passage-4
] (See above. Note 17 [http://www.accesstoinsight.org/lib/authors/nanananda/wheel183.html#fn-17
]), which compares each of the six senses to an ocean with its respective object as its 'force (of waves), and speaks of the arahant as one who has 'crossed over and gone beyond.'
A distinction has to be made between this 'dyad' (dvaya.m) and the 'dichotomy' (dvayataa) which is the theme in the Dvayataanupassana sutta of the sutta Nipaata, since the latter is set out in the form of contrasts (e.g., "'Whatever suffering arises, all that is due to ignorance' — this is one mode of contemplation: 'from the utter fading away and cessation of that very ignorance, there is no arising of suffering' — this is the second mode of contemplation" — (Sn. P. 141).http://www.accesstoinsight.org/tipitaka ... .than.html