In the essay “Of Friendship,” found in his Complete Essays (public library; public domain) — the same tome that gave us his timeless insights on studies and beauty — philosopher and scientific method pioneer Francis Bacon considers one of the greatest gifts of human existence:

A principal fruit of friendship, is the ease and discharge of the fulness and swellings of the heart, which passions of all kinds do cause and induce. We know diseases of stoppings, and suffocations, are the most dangerous in the body; and it is not much otherwise in the mind; you may take sarza to open the liver, steel to open the spleen, flowers of sulphur for the lungs, castoreum for the brain; but no receipt openeth the heart, but a true friend; to whom you may impart griefs, joys, fears, hopes, suspicions, counsels, and whatsoever lieth upon the heart to oppress it, in a kind of civil shrift or confession.

He then explores the second fruit of friendship:

The second fruit of friendship, is healthful and sovereign for the understanding, as the first is for the affections. For friendship maketh indeed a fair day in the affections, from storm and tempests; but it maketh daylight in the understanding, out of darkness, and confusion of thoughts. Neither is this to be understood only of faithful counsel, which a man receiveth from his friend; but before you come to that, certain it is, that whosoever hath his mind fraught with many thoughts, his wits and understanding do clarify and break up, in the communicating and discoursing with another; he tosseth his thoughts more easily; he marshalleth them more orderly, he seeth how they look when they are turned into words: finally, he waxeth wiser than himself; and that more by an hour’s discourse, than by a day’s meditation.

To this he adds a chief benefit of a friend — the capacity to neutralize our astounding gift for rationalization through wise counsel:

Add now, to make this second fruit of friendship complete, that other point, which lieth more open, and falleth within vulgar observation; which is faithful counsel from a friend. Heraclitus saith well in one of his enigmas, Dry light is ever the best. And certain it is, that the light that a man receiveth by counsel from another, is drier and purer, than that which cometh from his own understanding and judgment; which is ever infused, and drenched, in his affections and customs. So as there is as much difference between the counsel, that a friend giveth, and that a man giveth himself, as there is between the counsel of a friend, and of a flatterer. For there is no such flatterer as is a man’s self; and there is no such remedy against flattery of a man’s self, as the liberty of a friend. Counsel is of two sorts: the one concerning manners, the other concerning business. For the first, the best preservative to keep the mind in health, is the faithful admonition of a friend. The calling of a man’s self to a strict account, is a medicine, sometime too piercing and corrosive. Reading good books of morality, is a little flat and dead. Observing our faults in others, is sometimes improper for our case. But the best receipt (best, I say, to work, and best to take) is the admonition of a friend. It is a strange thing to behold, what gross errors and extreme absurdities many (especially of the greater sort) do commit, for want of a friend to tell them of them; to the great damage both of their fame and fortune: for, as St. James saith, they are as men that look sometimes into a glass, and presently forget their own shape and favor. As for business, a man may think, if he win, that two eyes see no more than one; or that a gamester seeth always more than a looker-on; or that a man in anger, is as wise as he that hath said over the four and twenty letters; or that a musket may be shot off as well upon the arm, as upon a rest; and such other fond and high imaginations, to think himself all in all. But when all is done, the help of good counsel, is that which setteth business straight. And if any man think that he will take counsel, but it shall be by pieces; asking counsel in one business, of one man, and in another business, of another man; it is well (that is to say, better, perhaps, than if he asked none at all); but he runneth two dangers: one, that he shall not be faithfully counselled; for it is a rare thing, except it be from a perfect and entire friend, to have counsel given, but such as shall be bowed and crooked to some ends, which he hath, that giveth it. The other, that he shall have counsel given, hurtful and unsafe (though with good meaning), and mixed partly of mischief and partly of remedy; even as if you would call a physician, that is thought good for the cure of the disease you complain of, but is unacquainted with your body; and therefore may put you in way for a present cure, but overthroweth your health in some other kind; and so cure the disease, and kill the patient. But a friend that is wholly acquainted with a man’s estate, will beware, by furthering any present business, how he dasheth upon other inconvenience. And therefore rest not upon scattered counsels; they will rather distract and mislead, than settle and direct.

Complete Essays is a timeless treasure in its entirety, covering such human essentials as love, anger, justice, revenge, ambition, and more.

Complement with C.S. Lewis on true friendship, Emerson on its two essential criteria, and Aristotle on the art of human bonds.