Q How did a young, progressive woman, raised in an atheist family, end up living in a cloistered convent?

A The first step happened when I was 15 and I first read the Gospels. I was startled, very deeply affected by that. I was unsettled completely.

Q In what way?

A I was upset. I thought, “I’ve lost 15 years of my life without this. Why didn’t I know about this?” And then I challenged my parents, who were not religious. I went to a parish in the harbour [in Barcelona] where people worked with the poor and the homeless, and I said to my parents, “You speak about social justice, but what are you doing about it? You criticize these people, but they are doing it.” So that was the first part of my journey.

Q When did you realize that the religious life might be for you?

A At the end of my medical training in Buffalo, N.Y., in 1995, we had to pass the board exam, and I needed a quiet place [in Spain] to prepare. I tried a monastery first, but they were full, so I tried the nuns. But I thought to myself, “Teresa, what kind of feminist are you in going there?”

Q You had a bias against nuns?

A Oh yes. I thought that intellectually it would not be an interesting or challenging place, so I would have no distractions from my studies. But then again, I said to myself, “You don’t know these nuns. Don’t stereotype! Don’t discard them before meeting them.”

Q And how was it?

A For the first time, I prayed the Psalms in the Benedictine way. We woke every day at 6 a.m. for the matins. Now, after 20 years of being a nun, I sometimes feel like, “Oh no, it’s so early! Do I have to wake up?” But not then. I was completely taken by it. I decided I wanted to be a nun. When I went to tell the abbess, she laughed. Since I’d been accepted at Harvard, she advised me to continue my studies and come back if I was still serious about the idea. I prayed on it the whole time I was away.

Q How do you reconcile being a feminist with your active role in the Catholic Church, an undeniably patriarchal institution?

A My foundational experience — whatever it was that happened to me — this is why I am where I am. It has nothing to do with the church being patriarchal or not. It’s simply about a human being who was touched by God.

If you were to ask me, “Are you sure it was God calling you?” I would say, “Yes, I am existentially sure.” But my intellect tells me I could be deceiving myself. It might have been a psychological need that just developed into this idea. Sometimes I imagine that when I go to the final judgment and I’m face to face with Jesus, he might say, “No, Teresa. It wasn’t me.” But I will tell him, “Okay. Fair enough. You know better, but I thought it was you. And that was enough for me to give my life to this.” I think he would like this answer.

Q I think he would too. But what about this question of patriarchy?

A I do call my church structurally misogynist. It’s not just a couple of priests here and there or a particular bunch of cardinals. The whole structure needs to be undone. Fully. Because it’s based on clericalism, and clericalism is based on ordination, and only males can be ordained and access the places where decisions are made. I find this completely sinful.

Q Are you optimistic that there could be changes to this structure in the future?

A I hope that eventually there will be, but I have no clue. I’ve studied theology and the history of the church — just when you think the Holy Spirit is going to break through, suddenly something happens and you find out — oh wait! Only a thousand more years. So who knows? Besides, this question is not what motivates me.

Q What does motivate you?

A The fascinating fact that God can be alive in me, and I in God. When we nuns get our rings, we’re asked to choose a motto to be inscribed in it. Mine has the Latin for “Love one another as I have loved you,” from the Gospel of John. That’s what motivates me.

Q What’s an issue that’s especially important to you these days?

A One key issue is the privatization of public health. I did my PhD in public health, so it’s an important area for me. We have a commitment to those more vulnerable than us. Should we just preach, “Each to his or her own?” Impossible. We have to take care of one another, and do it in a way that doesn’t discriminate based on money. Unfortunately, taking care of a diseased person has turned into a business.

Q Where do you see this happening?

A Everywhere. I’ve written much about the WHO [World Health Organization]. It’s becoming increasingly privatized, and this is a problem. It was founded in 1947 to be run by the contributions of the governments of the United Nations. In the 1970s, with the oil crisis, the contributions started dwindling, and some private funds started coming in. By the ’90s, the equilibrium was lost. Now, the private sector, especially the Bill and Melinda Gates Foundation but also Coca Cola and others, give large sums of money, but it comes with conditions.

Q I’ve heard you speak about the fallacy of capitalist freedom. Why call it a fallacy?

A If you choose freedom over equality, supposedly you are a capitalist. If you choose equality or social justice over freedom, supposedly you are a socialist or a communist. I say no. My theological understanding says freedom and justice cannot go against each other. That has to be a false freedom. What capitalism calls “freedom,” if you look at history, is in fact privilege. It’s freedom of the few.

At the beginning of capitalism was protectionism: governments decided to impose border taxes to protect certain national industries. But these industries, they were not national. They were private. The interests of these owners were protected, while the striking workers were being crushed. The children of these workers were the most unprotected of all. We still call this period “protectionism” because we look at history from the perspective of the few — the elite.

Q You’ve also said that change needs to come from the bottom up.

A For me this is a fundamental idea. Even within the church, I don’t believe that change can come from the top. I like Pope Francis, and I respect many political leaders. But in the end, all they can do is open up space for what comes from the bottom. Throughout history, when things have changed for the better, it was always from the bottom up.

Q Do you ever consider that you might have more influence if you weren’t a nun?

A There is no other way for me. This is who I am and my calling. I understand your question, and there’s logic to it. But don’t forget that the Holy Spirit touches the hearts of people, and you never know what might be kindled. I believe in doing my part and not being passive, but ultimately it’s all in God’s hands. So I trust. Simone Weil, a philosopher I admire, tells us through her teachings that all the world needs is people ready to be faithful to themselves and to their calling. Your call may not be a loud voice; it could be the subtlest inkling. Stay with it. Do whatever you have to do, but understand that it’s the voice of God. Just trust.

This interview has been condensed and edited.