I’ve been reading Sarah Bakewell’s delightful At the Existentialist Café, something of an existentialist study of the existentialist movement. The book follows the life, times, and beliefs of some of the 20th century’s most prominent existentialists, the German phenomenologist Edmund Husserl, his protégé Martin Heidegger, and continuing through the great French philosophers Simone de Beauvoir, Jean-Paul Sartre, Albert Camus, and Maurice Merleau-Ponty.

Along the way we meet many of their friends and colleagues – notable philosophers in their own right – whose lives are integral to Bakewell’s study but whose stories are not the focus of this particular work: Edith Stein, Emmanuel Levinas, Karl Jaspers, Hannah Arendt, Raymond Aron, Arthur Koestler, and many others.

I’m familiar with the famous works of these philosophers, but beyond a passing familiarity with the most prominent relationships and various author’s historical contexts, I hadn’t previously appreciated the deep, interconnected network of personal and philosophical relationships. The waves of history that brought these great philosophers together and ultimately tore them apart.

Phenomenology, which formed a basis for later existentialist thought, seeks to describe things as they are, as they present themselves. In this way, Bakewell’s book can be seen as a phenomenological study of generations of thinkers desperately exploring “how we can be free and behave well in a complicated world.” A world that saw two world wars, a massive calculated genocide, a showdown of super powers, and the threat of nuclear annihilation.

As someone interested in civil society, I see this question not simply as an individual one: how can I be free and behave well – but as a collective one: how can we all get along while wrestling with the challenges of being free and behaving well in a complicated world.

The story of the existentialist movement is one of carousing nights, passionate debates, and conversations at cafés. It’s a story of drinking, dancing, and sucking the very marrow out of life. It’s a story of being free.

But it’s also a story of fault and discord. Of unforgivable sins and spiteful fallings out. It a story of individuals struggling with the burden of what it means to be free: of trying to make the right choices and often making the wrong ones. Of people searching for what they stand for in difficult times – and breaking from those who disagree.

It’s a story of love and betrayal. Of betrayal and love.

The most notable villain in this story is Heidegger, whose Nazi activities make him still a controversial figure today. Elected rector of the University of Freiburg in 1933, Heidegger joined the Nazi party and was responsible for carrying out Reich law, including firing all Jewish professors and stripping emeritus faculty – such as his friend and former mentor Husserl – of their privileges. Heidegger’s personal notebooks from that time were published in 2014, revealing “philosophical thoughts alternating with Nazi-flavoured anti-Semitic remarks…Heidegger was a Nazi, at least for a while, and not out of convenience, but by conviction.”

Heidegger’s Nazism is topic much larger than this post, but needless to say, he fell out with his Jewish friends and colleagues. He rarely spoke with Husserl. In letters he tried to assure Hannah Arendt – for whom Heidegger had formerly been a lover – and mutual friend Karl Jaspers that he was not really a Nazi, but eventually they broke ties with him.

Edith Stein, who’d been a student of Husserl’s shortly before Heidegger, had converted to Christianity and joined a convent long before the war. She was detained, imprisoned , and murdered in a Nazi concentration camp.

But beyond the staggering actions of Heidegger, the story of existentialism tells of many more every day betrayals.

Emmanuel Levinas, another of Husserl’s students at a time of devotion to Heidegger, acted very much like a 23 year-old in 1929 following a debate between the magnetic Heidegger and old guard philosopher Ernst Cassirer. Cassirer’s wife, Toni, walked in on Heidegger’s students “satirically reenacting the debate.” Levinas played Cassirer, “dusting his hair with white talc and twirling it into a high quiff like an ice cream cone. Toni Cassirer did not find him funny. Years later, Levinas wished he had apologized to her for his irreverence.” Levinas – who was also Jewish – lost his love for Heidegger soon after.

Meanwhile, a tight-knit group of existentialists was forming in France. Simone de Beauvoir and her childhood friend Maurice Merleau-Ponty met Jean-Paul Sartre and his childhood friend Raymond Aron. Beauvoir and Sartre quickly became lovers and remained primary partners for the rest of their lives.  In a Parisan café, under the burden of German occupation, the pair met Albert Camus. Hungarian scholar Arthur Koestler also joined their circle.

And as the dark days of the war faded, there was a golden time of love, friendships, and good natured but passionate debates.

But such times were short lived. Intellectually attracted to communism, but dismayed by fascist actions, the existentialists found themselves pulled in different directions. Was the promising vision of communism worth holding on to given the actions taken in its name? Were the actions of fascist states forgivable given the great good given as reason? Capitalism was deeply flawed and the U.S. had its own sins – so was siding with them really any better?

It was dark, dramatic times.

Koestler threw a wine glass at Sartre and got into a scuffle with Camus. Aron moderated a panel where he allowed Sartre to be verbally ganged up on. Camus wrote pointed pieces attacking the  position of Sartre, who took no pause in firing back. Sartre attacked his old friend Merleau-Ponty, and they similarly fell out.

After the wine-glass incident, Koestler ran into Sartre and Beauvoir on the street – from a second hand account of Koestler’s point of view, Koestler suggested the three get together for lunch. “Koestler, you know that we disagree,” Beauvoir reportedly responded, “There no longer seems any point in our meeting.”

This is the fundamental question of civic life.

Can people who disagree so vehemently  about such high stakes things continue to coexist in a civic sense? If not, the alternative is to avoid such matter – to stick to safe topics like the weather.

But that is a basic betrayal of civic duty. It may maintain friendships, but at the cost of moral questioning and action. Perhaps small topics are best to avoid – but when the big things are at stake – with the nature of the state and the future of the global world hang in the balance, simply not discussing these topics is not an option.

Sartre, Camus, Beauvoir, Merleau-Ponty, Koestler, and Aron had to take a stand. Their views, voices, and actions mattered. But they found their divergences unmanageable – they could not be friends.

This poses a tremendous challenge to the basic premise of civic life: that each of our voices matter, and that we all must find ways to productive share and debate our views.