People think in heuristics. According to Dewey, the contribution of great ethical systems to moral reasoning is not so much in the system, but in the way they popularize certain heuristics, e.g., the greatest good for the greatest many, never treat someone merely as a means to an end, etc.
Heuristics are, strictly speaking, less rational than the formal procedures and underlying reasoning that give rise to them. That is, if we only apply the heuristic, we will likely come to conclusions sometimes which would not be derivable from (or may even be contrary to) the reasoning which gave rise to the heuristic in the first place. If this is true for heuristics derivable from rationally articulated systems of philosophy, how much more so for the unaccountable folk wisdom and traditions manifested in idioms and proverbs as well as the obscure teachings of sages and mystics?
Indeed, the ardent rationalist, treating proverbs as propositions, will point to exceptions as well as the existence of proverbs that directly contradict each other as proof that they are ultimately false or empty of content. This reduction of proverbs to mere propositions, however, completely misses their point.
Folk wisdom is not simply a storehouse of truisms, platitudes, and clever phrases. Folk wisdom is the contextual judgment necessary to apply these phrases correctly. And if the rationalist asks “What is the rule for the application of these phrases?” they have also missed the point. Indeed, if there was some rationally articulatable rule as to when one proverb was appropriate and when the other was appropriate, it would be the rule and there would be no need for the proverb. But this is mostly likely dissatisfying for the rationalist. “Am I just supposed to accept that A applies when A applies and B applies when B applies? That is circular and therefore useless.” Indeed, it is. The function of the proverb is articulate an intuited reaction rather than to govern what reaction ought be intuited. The existence of proverbs that directly contradict each other demonstrates that they are the cart and not the horse. It is by observing others using proverbs that we come to develop a sensibility about them.
But what of the wisdom of sages? The sage expresses herself in the form of a proverb and does not need a book to get there, but this does not mean there is no infrastructure. The sage, in contrast to the theorist, relates stories and, in living an exemplary life, creates stories, for which proverbs are the punchline. Consequently, the proverb is not the end of an argument but the beginning of an elaboration whose character will be oral and anecdotal. Rational and analytic tools can be brought to this endeavour but they will not be primary or determinative in the same way as they are for the theorist. This is why it is better to live with a sage than to study under one.
Among political theorists, Machiavelli comes closest to adopting this structure of teaching.