It is in relationships that we discover both our depths and our limits, there that we anneal ourselves and transcend ourselves, there that we are hurt the most and there that we find the most healing.

But despite what a crucible of our emotional and spiritual lives relationships are — or perhaps precisely because of it — they can be riddling and nebulous, destabilizing in their fluidity and ambiguity, leaving us grasping for the comforting solidity of categories and labels. The ancient Greeks, in their pioneering effort to order the chaos of the cosmos, neatly taxonomized them into filial love (the kind we feel for siblings, children, parents, and friends), eros (the love of lovers), and agape (the deepest, purest, most impersonal and spiritual love). After the Enlightenment discounted all love as a malfunction of reason, the Romantics reclaimed it and revised the ancient taxonomy into a hierarchy, under the tyranny of which we still live, placing eros at the pinnacle of human existence. And yet our deepest relationships — the ones in which we both become most fully ourselves and are most emboldened to change — tend to elude the commonplace classifications and to shape-shift across the span of life.

Simone de Beauvoir (January 9, 1908–April 14, 1986) was only nineteen when she wielded her uncommon intellect at these questions on the pages of her journal, later published as Diary of a Philosophy Student (public library). In between composing her resolutions for a life worth living, Beauvoir began thinking seriously about the nature of love, its dialogue with her own nature, what she may want of it and what it may demand of her — “in brief, how souls can interact with one another.” In the midst of an intellectual infatuation with a young man who would go on to become an eminent philosopher himself — not the one she would eventually marry in a convention-breaking union of minds — she examines the substance of the feeling:

To say that I love him, what does that mean? Does the word itself have a meaning?

Questioning the tangle of idolization and desire that masquerades as love, she grows suspicious of the very concept of personal love as an absurdity against the backdrop of the largest love we can carry:

When you love beings… not for their intelligence, etc., but for what they have in their very depths, for their soul… you love them equally: they are entireties, perfect inasmuch as they are (to be = perfection). Why then is there this desire to get closer? To know them, and thus to love them more perfectly for what they really are. What is surprising is not that we love them all, but rather that we prefer one of them.

Invoking the love she feels for her friends, the sum total of them, she writes:

Something sharp runs through me which is my love for them… This is not intellectual love. This is a love for souls, from all of me towards all of them in their entirety.

Over and over she returns to the elemental question:

What then is love? Not much, not much… Sensitivity, imagination, fatigue, and this effort to depend on another; the taste for the mystery of the other and the need to admire… What is worthwhile, is friendship… this profound mutual confidence between [two people], and this joy of knowing that the other exists.

Drawing on Hegel’s philosophy of freedom, in which for any conscious subject to be free means freeing the other, she arrives at a “formula” for the ideal friendship: “absolute reciprocity and the identity of consciousness.” The cultural ideal of romantic love, on the other hand, replaces this “absolute reciprocity” with engulfment and sublimation of one self into the other. She writes:

It seems to me that love should not make all else disappear but should simply tint it with new nuances; I would like a love that accompanies me through life, not that absorbs all my life.

This, of course, is Rilke’s model of a perfect relationship — one in which “the highest task of a bond between two people [is] that each should stand guard over the solitude of the other” — consonant with Octavio Paz’s lovely definition of love as “a knot made of two intertwined freedoms.”

Beauvoir ultimately found it not in romantic love but in the deepest friendship of her life — that with Zaza, her childhood best friend.

A year older than her and also enamored of books, Zaza was the only one with whom the young Simone could have “real conversations.” In Memoirs of a Dutiful Daughter (public library) — the first volume of her autobiography, largely a loving memorial to this formative relationship — she would write of talking to Zaza:

My tongue was suddenly loosened, and a thousand bright suns began blazing in my breast; radiant with happiness.

When Zaza’s dress caught fire and charred her leg to the bone, she endured the long convalescence valiantly, then went on to climb trees and do cartwheels, to play the piano and the violin. Beauvoir relays a moment radical in the context of early twentieth-century French bourgeoise society, emblematic of Zaza’s defiant spirit and playful disdain for convention:

One year at a music recital [Zaza] did something while she was playing the piano which was very nearly scandalous. The hall was packed. In the front rows were the pupils in their best frocks, curled and ringleted and beribboned, who were awaiting their turn to show off their talents. Behind them sat the teachers and tutors in stiff black silk bodices, wearing white gloves. At the back of the hall were seated the parents and their guests. Zaza, resplendent in blue taffeta, played a piece which her mother thought was too difficult for her; she always had to scramble through a few of the bars: but this time she played it perfectly, and, casting a triumphant glance at [her mother], put out her tongue at her! All the little girls’ ringlets trembled with apprehension and the teachers’ faces froze into disapproving masks. But when Zaza came down from the platform her mother gave her such a light-hearted kiss that no one dare reprimand her. For me this exploit surrounded her with a halo of glory. Although I was subject to laws, to conventional behaviour, to prejudice, I nevertheless liked anything novel, sincere, and spontaneous. I was completely won over by Zaza’s vivacity and independence of spirit.

This strength of spirit, this defiance of the givens, is what the young Simone most admired about her friend — it emboldened her to defy convention in her own life.

Part of the unexamined convention Beauvoir had internalized growing up was the belief that “in a well-regulated human heart friendship occupies an honourable position, but it has neither the mysterious splendour of love, nor the sacred dignity of filial devotion.” And yet through her relationship with Zaza, she came to question this limiting “hierarchy of the emotions” and to see friendship as the deepest stratum of connection. “I loved Zaza with an intensity which could not be accounted for by any established set of rules and conventions,” she would reflect decades later.

It was only in Zaza’s absence — absences inflicted by their families and school schedules and the general fractures of continuity that life presents — that Beauvoir came to grasp the importance, the consolation, the salvation of her friend’s presence:

So total had been my ignorance of the workings of the heart that I hadn’t thought of telling myself: ‘I miss her.’ I needed her presence to realize how much I needed her. This was a blinding revelation. All at once, conventions, routines, and the careful categorizing of emotions were swept away and I was overwhelmed by a flood of feeling that had no place in any code. I allowed myself to be uplifted by that wave of joy which went on mounting inside me, as violent and fresh as a waterfalling cataract, as naked, beautiful, and bare as a granite cliff.

In her diary, she recounts one such reunion during her freshman year as a philosophy student:

I found Zaza again! All last year and during this vacation, I believed that she was far, very far from me. And there she was infinitely close by and now we are going to be true friends. Oh! What a beautiful meaning this word has! Never have we spoken so, and I was not even hoping that it could happen — but why, too, never believe in happiness… Let us bring our two solitudes together!… When I had left her, I experienced one of the most beautiful hours of my life, my love and my friendship both greater from their union.

Beauvoir was discovering deep friendship as safer and more resilient than romance, free from “the great hatreds of love, the irremediable pride, the passionate ruptures, the mutual tortures,” never “introducing jealousy, demands, and doubts.” To have what the ancient Celts called anam cara — “soul friend” — asks everything of us, invites all the parts we live with and urges us to show up whole, yet demands nothing.

Looking back on her life, Beauvoir reflects:

I didn’t require Zaza to have any such definite feelings about me: it was enough to be her best friend. The admiration I felt for her did not diminish me in my own eyes. Love is not envy. I could think of nothing better in the world than being myself, and loving Zaza.

Midway through Beauvoir’s sophomore year, Zaza died suddenly and mysteriously — an illness swift and merciless as an owl. She was 21. Amid the savage grief, Beauvoir turned even more sharply toward philosophy, seeking its eternal consolations. Across the sweep of the years and decades, Zaza’s inextinguishable presence never left her life. (“No one you love is ever dead,” Ernest Hemingway wrote around that time in a letter of consolation to an inconsolable friend.) Loving Zaza had ignited Beauvoir’s becoming, setting her on the course of who she would become — one of humanity’s most daring breakers of convention, her ideas reaching into the depths of her time, shaping the times to come, touching the lives of generations of strangers the way a true friendship does. Touching mine. Perhaps touching yours.

Complement with Seneca on true vs. false friendship and Little Prince author Antoine de Saint-Exupéry on losing a friend, then revisit Simone de Beauvoir on how chance and choice converge to make us who we are and the art of growing older.