Those purposes for which speech was given to us, to wit, giving or receiving information or pleasure

From The Autobiography of Benjamin Benjamin Franklin. Wisdom that is especially relevant to our public discourse today.

While I was intent on improving my language, I met with an English grammar (I think it was Greenwood's), at the end of which there were two little sketches of the arts of rhetoric and logic, the latter finishing with a specimen of a dispute in the Socratic method; and soon after I procur'd Xenophon's Memorable Things of Socrates, wherein there are many instances of the same method. I was charm'd with it, adopted it, dropt my abrupt contradiction and positive argumentation, and put on the humble inquirer and doubter. And being then, from reading Shaftesbury and Collins, become a real doubter in many points of our religious doctrine, I found this method safest for myself and very embarrassing to those against whom I used it; therefore I took a delight in it, practis'd it continually, and grew very artful and expert in drawing people, even of superior knowledge, into concessions, the consequences of which they did not foresee, entangling them in difficulties out of which they could not extricate themselves, and so obtaining victories that neither myself nor my cause always deserved. I continu'd this method some few years, but gradually left it, retaining only the habit of expressing myself in terms of modest diffidence; never using, when I advanced anything that may possibly be disputed, the words certainly, undoubtedly, or any others that give the air of positiveness to an opinion; but rather say, I conceive or apprehend a thing to be so and so; it appears to me, or I should think it so or so, for such and such reasons; or I imagine it to be so; or it is so, if I am not mistaken. This habit, I believe, has been of great advantage to me when I have had occasion to inculcate my opinions, and persuade men into measures that I have been from time to time engaged in promoting; and, as the chief ends of conversation are to inform or to be informed, to please or to persuade, I wish well-meaning, sensible men would not lessen their power of doing good by a positive, assuming manner, that seldom fails to disgust, tends to create opposition, and to defeat everyone of those purposes for which speech was given to us, to wit, giving or receiving information or pleasure. For, if you would inform, a positive and dogmatical manner in advancing your sentiments may provoke contradiction and prevent a candid attention. If you wish information and improvement from the knowledge of others, and yet at the same time express yourself as firmly fix'd in your present opinions, modest, sensible men, who do not love disputation, will probably leave you undisturbed in the possession of your error. And by such a manner, you can seldom hope to recommend yourself in pleasing your hearers, or to persuade those whose concurrence you desire. Pope says, judiciously:

"Men should be taught as if you taught them not,
And things unknown propos'd as things forgot;"