If a requirement can be easily rephrased as a criterion in a decision problem (as I argued elsewhere), then what is advice?
In the context of a decision problem, advice is one of two things, is information that has one of two roles: advice either brings another option, another alternative into the decision problem, something the decision maker did not consider, or advice is intended to change some other part of the decision problem – to reverse a preference, to tone down or emphasize some criteria over others, to change perceptions of uncertainty, more generally to change elements of the decision problem, to rewrite the decision problem.
Machiavelli’s The Prince is filled with advice. If a prince’s choices are imagined through the lens and language of decision analysis, with its criteria, preferences, uncertainty, probability, utility, and optimization of expected utility, then the following passage is filled with advice that narrows down a prince’s choices of what to, when they have nothing else to do.
“But to exercise the intellect the prince should read histories, and study there the actions of illustrious men, to see how they have borne themselves in war, to examine the causes of their victories and defeat, so as to avoid the latter and imitate the former; and above all do as an illustrious man did, who took as an exemplar one who had been praised and famous before him, and whose achievements and deeds he always kept in his mind, as it is said Alexander the Great imitated Achilles, Caesar Alexander, Scipio Cyrus. And whoever reads the life of Cyrus, written by Xenophon, will recognize afterwards in the life of Scipio how that imitation was his glory, and how in chastity, affability, humanity, and liberality Scipio conformed to those things which have been written of Cyrus by Xenophon. A wise prince ought to observe some such rules, and never in peaceful times stand idle, but increase his resources with industry in such a way that they may be available to him in adversity, so that if fortune chances it may find him prepared to resist her blows.” [1, Chapter XIV]
While the above narrows down options, the following narrows down criteria in light of desirable and opposing outcomes; it is a passage with ideas frequently associated with Machiavelli.
“Upon this a question arises: whether it be better to be loved than feared or feared than loved? It may be answered that one should wish to be both, but, because it is difficult to unite them in one person, it is much safer to be feared than loved, when, of the two, either must be dispensed with. Because this is to be asserted in general of men, that they are ungrateful, fickle, false, cowardly, covetous, and as long as you succeed they are yours entirely; they will offer you their blood, property, life, and children, as is said above, when the need is far distant; but when it approaches they turn against you. And that prince who, relying entirely on their promises, has neglected other precautions, is ruined; because friendships that are obtained by payments, and not by greatness or nobility of mind, may indeed be earned, but they are not secured, and in time of need cannot be relied upon; and men have less scruple in offending one who is beloved than one who is feared, for love is preserved by the link of obligation which, owing to the baseness of men, is broken at every opportunity for their advantage; but fear preserves you by a dread of punishment which never fails.” [1, Chapter XVII]
- Nicolo Machiavelli, The Prince, 1998, translated by W. K. Marriott. https://www.gutenberg.org/files/1232/1232-h/1232-h.htm