"It's in dependence on a pair that consciousness comes into
play. And how does consciousness come into play in dependence on a
pair? In dependence on the eye & forms there arises
eye-consciousness. The eye is inconstant, changeable, of a nature
to become otherwise. Forms are inconstant, changeable, of a nature
to become otherwise. Thus this pair is both wavering &
fluctuating — inconstant, changeable, of a nature to become
otherwise.
"Eye-consciousness is inconstant, changeable, of a nature to
become otherwise. Whatever is the cause, the requisite condition,
for the arising of eye-consciousness, that is inconstant,
changeable, of a nature to become otherwise. Having arisen in
dependence on an inconstant factor, how could eye-consciousness be
constant?
"The coming together, the meeting, the convergence of these
three phenomena is eye-contact. Whatever is the cause, the
requisite condition, for the arising of eye-contact, that is
inconstant, changeable, of a nature to become otherwise. Having
arisen in dependence on an inconstant factor, how could eye-contact
be constant?
"Contacted, one feels. Contacted, one intends. Contacted, one
perceives. These phenomena are both wavering & fluctuating —
inconstant, changeable, of a nature to become otherwise. This is
how it's in dependence on a pair that eye-consciousness comes into
play.
"In dependence on the ear & sounds there arises
ear-consciousness...
"In dependence on the nose & aromas there arises
nose-consciousness...
"In dependence on the tongue & flavors there arises
tongue-consciousness...
"In dependence on the body & tactile sensations there arises
body-consciousness...
"In dependence on the intellect & ideas there arises
intellect-consciousness. The intellect is inconstant, changeable,
of a nature to become otherwise. Ideas are inconstant, changeable,
of a nature to become otherwise. Thus this pair is both wavering
& fluctuating — inconstant, changeable, of a nature to become
otherwise.
"Intellect-consciousness is inconstant, changeable, of a nature
to become otherwise. Whatever is the cause, the requisite
condition, for the arising of intellect-consciousness, that is
inconstant, changeable, of a nature to become otherwise. Having
arisen in dependence on an inconstant factor, how could
intellect-consciousness be constant?
"The coming together, the meeting, the convergence of these
three phenomena is intellect-contact. Whatever is the cause, the
requisite condition, for the arising of intellect-contact, that is
inconstant, changeable, of a nature to become otherwise. Having
arisen in dependence on an inconstant factor, how could
intellect-contact be constant?
"Contacted, one feels. Contacted, one intends. Contacted, one
perceives. These phenomena are both wavering & fluctuating —
inconstant, changeable, of a nature to become otherwise. This is
how it's in dependence on a pair that intellect-consciousness comes
into play."
http://www.accesstoinsight.org/tipitaka/sn/sn35/sn35.093.than.html