Mīmāmsa Sūtra 01.01.04

satsamprayoge puruṣasyendriyāṇāṃ buddhijanma tatpratyakṣamanimittaṃ vidyamānopalambhanatvāt ॥4॥

Direct perception arises when the senses of a person come into contact with an existent object; this cognition is direct. Because it apprehends what is present, it fails to show the cause.