I observe this practice in my travels, in order to learn something through the communication of others (which is one of the most beautiful lessons that can be learned), I always allow the conversation to cover subjects that they know best.
Let it be enough for the ferryman to talk about the winds, To the herder about the bulls and as for their wounds, let the warrior tell; so too the shepherd about the herds. (Propertius)
For it happens most often the other way around, that everyone chooses to talk about someone else’s job than their own, considering it as gaining a new reputation. Witness the reproach that Archidamus made to Periander, that he gave up the glory of being a good doctor to acquire that of being a bad poet.
See how extensively Caesar goes to make us hear of his inventions in building bridges and engines; and how much he goes into detail about the price, where he talks about the offices of his profession, his valour and the conduct of his militia. His exploits verify him as an excellent captain: he wants to make himself known as an excellent engineer, a quality that is by no means unique.
A man of the legal vocation visited a study recently, furnished with all kinds of books of his trade, and of all other kinds, and found in them no opportunity to converse. But he stopped to comment harshly and masterfully on a barricade lodged on the spiral stairwell of the study, which a hundred captains and soldiers encounter every day, without remark and without offense.
The old Dionysius was a very great warlord, as was fitting for his fortune; but he worked hard to make poetry his main recommendation, even though he knew nothing about it.
A lazy ox desires to ride a horse, a horse desires to plow. (Horace)
With this approach you never do anything worthwhile.
So you should always reject the architect, the painter, the shoemaker, and so on, each to his own game. And, on that note, when reading stories, which is the subject of all subjects, I have made it a habit to consider who the writers are: if they are people whose only profession is literature, I learn mainly from their style and language. If they are doctors, I believe them more readily in what they tell us about the temperature of the air, the health and complexion of Princes, wounds and illnesses. If they are lawyers, we must take from them controversies of law, laws, the establishment of police forces and similar matters. If Theologians, the affairs of the Church, Ecclesiastical censures, dispensations and marriages. If courtiers, manners and ceremonies. If soldiers, what pertains to their office, and principally the deductions of exploits, where they have been in person. If Ambassadors, the maneuvers, intelligence and practices, and the manner of conducting them.
For this reason, what I would have passed on to someone else, without dwelling on it. I have weighed and noted in the history of the Lord of Langey, who is very knowledgeable in diplomacy. This is because, after having recounted beautiful remonstrances of Emperor Charles V, made in the consistory in Rome, the Bishop of Masconet presented the Lord of Velly, our Ambassadors, where he had mixed several outrageous words against us, and among others that, if his Captains, soldiers and subjects had no other loyalty and skill in military matters than those of the King, he would immediately put a rope around his own neck and go to beg for mercy (and he seems to have believed this, for two or three times in his life he repeated these same words); also that he challenged the King to fight him in shirt and sword and dagger, in a boat, the said Lord of Langey, according to his story, adds that the said Ambassadors, making an announcement to the King of these things, concealed the greater part of them from him, even concealing from him the two preceding items.
Now, I found it very strange that it should be in the power of an ambassador to dispense with the warnings he must give to his master, even of such consequence, coming from such a person, and said in such a large assembly. And it seemed to me that the office of the servant was to faithfully represent things in their entirety, as they have happened: so that the freedom to order, judge and choose remains with the master.
For to alter or conceal the truth from him, for fear that he might seize it differently than he should, and that this might push him into some bad party, and all the while leaving him ignorant of his affairs: that would have seemed to me to belong to the one who gives the law, not to the one who receives it, to the guardian and schoolmaster, not to the one who should consider himself inferior, not only in authority, but also in prudence and good counsel.
In any case, I would not want to be served in this small way. We so willingly withdraw from command under any pretext, and usurp mastery. Everyone so naturally aspires to freedom and authority that no utility should be so dear to the superior, coming from those who serve him, as their naive and simple obedience should be dear to him. The office of commander is corrupted when one obeys out of discretion, not out of subjection.
And Publius Crassus, whom the Romans considered five times fortunate when he was consul in Asia, having ordered a Greek engineer to bring him the larger of the two ship’s masts he had seen in Athens, for some battery device he wanted to make, this one, under the pretext of his knowledge, took it upon himself to choose otherwise, and chose the smallest and, according to the reason of his art, the most convenient. Crassus, having patiently listened to his reasons, had him whipped soundly: considering the interest of discipline more than the interest of the work.
On the other hand, however, one could also consider that such constrained obedience belongs only to precise and predetermined commands. Ambassadors have a freer role, which, in many respects, depends entirely on their own judgment: they do not simply execute, but also form and shape the will of their master through their advice.
In my time, I have seen persons in command who claimed to have obeyed the words of the King’s letters rather than the affairs that were close to them. Men of understanding still accuse the practice of the Persian kings for cutting their agents and lieutenants into such short pieces that they had to resort to their orders for the smallest things. This delay, over such a long period of domination, often caused considerable damage to their affairs. And Crassus, writing to a man in the trade and giving him advice on the use to which he intended this farm, did he not seem to enter into a discussion of his deliberation and invite him to opine?