Ludwik Zamenhof was born in 1859 in a small city in Poland. His family was Jewish, and the area he grew up in also had factions of Germans, Russians, and Poles, all of whom mutually distrusted one another. During his childhood, Zamenhof developed a theory: these groups would never get along without a common, neutral language to communicate with people in the other groups. Zamenhof considered the possibility of using existing languages for this purpose—such as Latin and Greek—but decided that the cost to learn them was too high. So he invented his own.

Esperanto, as Zamenhof’s language came to be known, sought to take familiar Indo-European root words and cast them in a language without verb conjugations, cases, gender, or any of the elements which make a language like German or Russian so difficult to learn. He was nineteen when he first unveiled the language to the public. Zamenhof’s goal was not just to create a language that was easy to learn, but to create a language that would put the different peoples of Europe on a footing of mutual disadvantage—and therefore, he hoped, equality.

As far as invented languages go, Esperanto has enjoyed more success than most. You can study it on Duolingo. It’s a staple of popular culture; for example, I recently saw in an episode of the TV show Billions, where it is being learned by the character Michael Wagner. But mostly, this success has been on the linguistic front. People find the language interesting. But it hasn’t been especially useful as a basis for utopia.

In a way, Zamenhof’s Esperanto is a microcosm of the system of values more generally known as “humanism.” There are many shades of humanism, but at their core lies a belief that understanding, connection, and even mutual admiration among different kinds of people is not only possible but paramount to a meaningful life. If we could all converse with one another, understand one another—then maybe we’d stand a chance of constructing the kind of society we all want to live in.

But while Esperanto embodies the aspirations of humanism, it also is emblematic of its tensions. In theory, getting people to celebrate the many ways of being human is an ideal worth striving for. In practice, it is a difficult one to achieve. When it comes to the ways of being humans, what all humans have in common is that they prefer their own.

The fundamental impulse of humanism is to grapple with this tension, and it is the subject of the latest book by author Sarah Bakewell. In it, she surveys 700 years of humanist thought—with each thinker bringing a personal perspective to the shared problem of what it means to value human life and society in an abstract sense. The experience of reading Bakewell’s book is to hear the echoing conversation of the ages. One of the ways of reading humanism is to see it as a means of participating in this conversation. It’s a notion I think is rather beautiful.

Her book is Humanly Possible: Seven Hundred Years of Humanist Freethinking, Enquiry and Hope. It’s available now.