“Ponder for a long time whether you shall admit a given person to your friendship; but when you have decided to admit him, welcome him with all your heart and soul,” Seneca wrote in considering true and false friendship two millennia before we commodified the word “friend” in the marketplace of loneliness we call social media.

It is easy to forget now how hard-earned that entry into the heart and soul is, and how precious. “Old friends cannot be created out of hand,” Little Prince author Antoine de Saint-Exupéry wrote in the wake of losing a friend, mourning “the treasure of common memories, of trials endured together, of quarrels and reconciliations and generous emotions.” Pulsating beneath his bittersweet lament is the knowledge that the treasure is not found but created — or, rather, co-created. It is more precious and more total than the romantic love our culture fetishizes, for a deep friendship courses through every true love, and it is always more enduring — true friends are the other significant others, often outlasting spouses, often outpacing siblings in running to the rescue of the heart. Such friendships are the hard work of truth and tenderness, sustained by an unfaltering commitment to showing up, a promise of absolute sincerity, and a quality of presence that leaves each aglow with the sense of being treasured.

How to do that work, how to attain the skills required for it and bear the vulnerabilities inherent to it, is what Alain de Botton takes up in the School of Life primer Secrets of Successful Friendships (public library) — a pointed, poignant field guide to cultivating meaningful connection in a world where loneliness looms oceanic as night.

At the heart of the book is the insistence that friendship — something “tender, fundamental, and emotionally sustaining” — is “as significant and as rare” as romantic love (a case Andrew Sullivan made exquisitely two decades earlier), yet our culture gives us no education in it while drowning us in narrow models of romantic love as the pinnacle of emotional achievement.

This commodification and devaluation of deep friendship is the turbine of our modern loneliness. A century and a half after Thoreau, brilliant and lonely, rued that “we feel a yearning to which no breast answers” and ultimately “walk alone,” De Botton observes that many of us “return home from parties dissatisfied and confused.” Defining friendship as “a sense that in the company of a very special person, we will at last be able to share the most vulnerable and fragile sides of ourselves and be witnessed in our true, unadorned state,” he celebrates it as an antidote to the loneliness and isolation of feeling those sides unwitnessed:

Loneliness can coexist alongside an outwardly highly cheerful and easy manner and even — paradoxically — alongside the possession of many so-called “friends”… The lonely may hold their own brilliantly at a party; they might be married, have children and more often than not be out in the evenings.

[…]

We are lonely because we are refusing to accept as genuine those cheap, counterfeit images of friendship promoted by a sentimental world keen to disguise the challenges of real connection. Those who feel a lack of friendship most deeply may simply be those who cleave most intensely and sincerely to its genuine promises.

More than a salve for the existential loneliness we are born into, the essential purpose of friendship is emotional growth:

In the company of a real friend, we should aspire to become wiser, more sensitive, more able to cope with the complexity of existence, more resilient and more generous.

Friendship, however, is not a unitary phenomenon — there are as many species of it as there are species of loneliness. He writes:

We tend to think of friendship as a unitary category, but, in reality, there are a number of different kinds of friendship, each of which is specifically adapted to addressing a particular kind of loneliness. We might say that there are as many kinds of friend as there are ways of feeling isolated.

He offers a taxonomy that includes such species as the emotional confidante, the thinking partner, and the counterpoint. (It is the luck of a lifetime to find a friend who can play many of these roles, and the work of a lifetime to nurture that friendship.)

The deepest friendships offer us a “true and fulfilling togetherness” that can help us “feel reconciled to our own company,” for they are often the twining of two parallel solitudes. Such friendships are not a matter of luck — just as chance and choice converge to make us who we are, chance may place someone wonderful in our path, but it is by choice — a daily choice — that we endeavor to walk together in the same direction and grow along the way.

De Botton writes:

True friendship is a skill, not a piece of divine inspiration. Those who find it are not simply lucky: they understand certain crucial ideas; they are guided by specific insights into themselves and other people. And these ideas and insights can be explained and described in precise ways. We don’t have to be born with innate talents for being, or making, a good friend; the capacities can be acquired via the right kind of education.

In the remainder of Secrets of Successful Friendships, De Botton offers the rudiments of such an education, from the enemies of friendship (overcommitment, envy, “the absence of shared challenges”) to its pillars (deep listening, acts of service, horizontal conversations) to its fate in the age of AI. Couple it with this excellent Where Shall We Meet conversation with Alain de Botton about the subtleties and varieties of friendship, then revisit this introvert’s guide to friendship from Thoreau and Alain de Botton on romantic love.