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The contexts in which the term is located are, on the whole, psychological in their import. The Madhupiṇḍika Sutta (MN 18) points to the fact that papañca is essentially connected with the process of sense perception, and so also does the Kalahavivāda Sutta (Snp 4.11) when it emphatically states that papañca-saṅkhā have their origin in sense perception (saññā-nidānā hi papañca-saṅkhā). The following formula of sense perception occurring in the Madhupiṇḍika Sutta may however be regarded as the locus classicus, as it affords us a clearer insight into the problem of papañca:
“Visual consciousness, brethren, arises because of eye and material shapes; the meeting of the three is sensory impingement (phassa, contact); because of sensory impingement arises feeling; what one feels one perceives; what one perceives, one reasons about; what one reasons about, one turns into papañca; what one turns into papañca, due to that papañca-saññā-saṅkhā assail him in regard to material shapes cognisable by the eye belonging to the past, the future and the present. And, brethren, auditory consciousness arises because of ear and sounds; … olfactory consciousness arises because of nose and smell; … gustatory consciousness arises because of tongue and tastes; … bodily consciousness arises because of body and touches; … mental consciousness arises because of mind and mental objects; … belonging to the past, the future and the present.”
This passage indicates that papañca signifies the final stage in the process of sense-cognition. The term definitely concerns the grosser conceptual aspect of the process, since it is a consequent to vitakka (reasoning) which presupposes language. Hence we should determine how papañca differs from—nay, marks a development on—vitakka (reflection, thought, thinking).