Barbara Ehrenreich is a scientist, feminist, activist, atheist and rationalist. As an investigative journalist, she specializes in uncovering insidious oppression, from scraping by on a minimum wage (Nickel and Dimed: On (Not) Getting By in America, 2001) to the prosperity gospel (Bright-Sided: How Positive Thinking Is Undermining America, 2009). In other words, she’s allergic to bullshit.

Perhaps that’s why an inexplicable adolescent experience rocked Ehrenreich to the core: A series of dissociative episodes culminated at age 17, when an early morning walk through Lone Pine, California revealed a mystical presence. For lack of more accurate terminology, she would later describe the encounter as seeing “God.”

“I had tried to put this out of my mind in my ‘20s, this strange experience that I had in my teenage years. Mental experience, I should say—there’s not much physical evidence for it,” says Ehrenreich, who rediscovered her teenage journal while preparing her papers for donation to Harvard’s Schlesinger Library. The journal stayed with its author. “This is a subject you can’t bring up. All these years, I made a couple of feeble attempts only to see the other people turn away or change the subject.”

Living with a Wild God: A Nonbeliever’s Search for the Truth about Everything represents Ehrenreich’s eventual refusal to change the confounding subject. Those big questions—who am I? why am I here? who or what else is out there?—came naturally in her younger years, before being stamped out by adulthood’s more pragmatic concerns. But when faced with the question “What have you learned since you wrote this?” posed in a journal entry circa July 1958, Ehrenreich felt it was time to revisit the events that led to her current beliefs.

“I personally came around to the idea that what happened to me was an encounter with some ‘other’ than myself, and I could not let myself think that for many years because I’m such an über-atheist,” she says. “I’m not saying this other is ‘God’ or anything like anybody’s god, but it is something other than me or another human.”

It’s certainly not an inherited god: Ehrenreich was born to firm atheists in Butte, Montana. (A grandmother was famous for flinging the crucifix across the room when a priest attempted to administer last rites.) “I can’t recall a specific conversation on the subject of death, but I know exactly what the response would have been: There is no afterlife; we are here and then we’re gone. Death is a fact; get used to it. And why are you just standing around with nothing to do?” she writes. She was encouraged to excel at science and did, studying chemistry and physics at Reed College and earning a Ph.D. in cell biology from Rockefeller University.

Ehrenreich’s scientific mind objects to whatever stymies inquiry—including the lack of vocabulary, beyond “religious experience,” to describe what happened in Lone Pine. “I never wanted to write a memoir. I always thought ‘Oh, that would be so vain, so self-involved,’ and to tell you the truth, I originally wanted to write a history of religion. I had my own theories, and what I ended up doing was wrapping those thoughts into a narrative framework,” says Ehrenreich.

Among them are: “An equation is static and can be mistaken for a tautology, but an algorithm is a recipe for motion and growth,” and “...the great, unforgivable crime of the monotheistic religions has been to encourage the conflation of authority and benevolence, of hierarchy and justice.” These cumulative beliefs undergird Ehrenreich’s secular humanism. “Morality, as far as I could see, originates in atheism and the realization that no higher power is coming along to feed the hungry or lift the fallen. Mercy is left entirely to us,” she writes.

“In some ways this book is as much a critique of science as it is of religion or anything else. It’s been a science that says, ‘The world is dead, animals have no consciousness or feelings, it’s only Man and the universe.’ It’s a species-wide hubris,” she says.

Unlike her previous books, which clearly agitate for social change, Living with a Wild God doesn’t advance a specific action program (beyond contemplation and discussion). What it shares with them is Ehrenreich’s perpetual willingness to use her experience to advance the collective consciousness.

“Experience—empirical experience—requires me to keep an open mind. And human solidarity, which is the only reason for writing a book, requires that I call on others to do so also,” she writes.

Megan Labrise is a freelance writer and columnist based in New York. Follow her on Twitter.