From the Madhupindika Sutta (MN18):
"Dependent on eye & forms, eye-consciousness arises. The meeting of
the three is contact. With contact as a requisite condition, there is
feeling. What one feels, one perceives (labels in the mind). What one
perceives, one thinks about. What one thinks about, one objectifies.
Based on what a person objectifies, the perceptions & categories of
objectification assail him/her with regard to past, present, & future
forms cognizable via the eye.
"Dependent on ear & sounds, ear-consciousness arises...
"Dependent on nose & aromas, nose-consciousness arises...
"Dependent on tongue & flavors, tongue-consciousness arises...
"Dependent on body & tactile sensations, body-consciousness arises...
"Dependent on intellect & ideas, intellect-consciousness arises. The
meeting of the three is contact. With contact as a requisite
condition, there is feeling. What one feels, one perceives (labels in
the mind). What one perceives, one thinks about. What one thinks
about, one objectifies. Based on what a person objectifies, the
perceptions & categories of objectification assail him/her with regard
to past, present, & future ideas cognizable via the intellect.