In an oral culture, to think through something in non-formulaic, non-patterned, non-mnemonic terms, even if it were possible, would be a waste of time, for such thought, once worked through, could never be recovered with any effectiveness, as it could be with the aid of writing. It would not be abiding knowledge but simply a passing thought, however complex. Heavy patterning and communal fixed formulas in oral cultures serve some of the purposes of writing in chirographic cultures, but in doing so they of course determine the kind of thinking that can be done, the way experience is intellectually organized. In an oral culture, experience is intellectuallized mnemonically.
Of course, all expression and all thought is to a degree formulaic in the sense that every word and every concept conveyed in a word is a kind of formula, a fixed way of processing the data of experience, determining the way experience and reflection are intellectually organized, and acting as a mnemonic device of sorts. Putting experience into any words (which means transforming it at least a little bit -- not the same as falsifying it) can implement its recall. The formulas characterizing orality are more elaborate, however, than are individual words, though some may be relatively simple: the Beowulf-poet's 'whale-road' is a formula (metaphorical) for the sea in a sense in which the term 'sea' is not.
Walter J. Ong, Orality and Literacy: The Technologizing of the Word , 63-64.