BustedHalo: At first, I thought you pulled some stunts just for entertainment. Like carrying around pebbles to stone people. But the more I read, the more I realized that by taking everything so literally, you gained some insight you could not have drawn unless you’d gone to such extremes.

A.J. Jacobs: Well, I think so, and that’s nice of you to say. I mean, it was a huge learning experience for me, and much of what I learned came from the living through it. I could have just read a lot of Bible commentaries, but that would not have allowed me to learn through experience. You know, like, it’s one thing to learn about Rome by just reading travel books. It’s another to go there, and to walk the streets and to eat the pasta yourself.

BH: Which was why you built a hut in the middle of your New York apartment—to get a sense for, as best you could, what the ancients experienced celebrating the Feast of Tabernacles.

AJJ: I felt like I was walking in their sandals, if you will. And that was another amazing revelation I had doing this project—how much behavior shapes our thought. They talk about this in cognitive psychology: If you act a certain way, you will become that way. This happened to me, ethically. I wasn’t allowed to gossip, so eventually I had fewer things I could gossip about. C.S. Lewis wrote about this phenomenon—that pretending to be better than you are is better than nothing. And it may even be the first step to self-improvement.

BH: Prayer is another example. You prayed as often as some of the most devout believers I know, and yet you’re agnostic, unsure if anyone or anything ever heard you. Still, regular prayer yielded some surprising benefits.

AJJ: Definitely. I talk about how it was a very weird experience for me to pray. I’d never done it before, and I’d rarely said the word “Lord” without following it by “of the Rings.” So here I was praying and feeling uncomfortable, but eventually I became comfortable with it, and even started to really relish prayer. Especially two kinds: prayers of thanks, and prayers for other people. I really took to those forms.

BH: Why? Was it simply because they made you more appreciative and less wrapped up in yourself?

AJJ: That’s it exactly. I still don’t know if my intercessory prayers did anything for others. Did my friend heal faster because I prayed for him? I remain agnostic about that. But it was good for me in the sense that I viewed it as moral weight training. Here were 10 minutes a day that I was forced to think about other people. I couldn’t be self-absorbed and selfish. Prayer helps you get beyond yourself, which can be liberating.

BH: You write that you suffer a mild case of obsessive-compulsive disorder. Interestingly, but not surprisingly, you discovered that living biblically suited your O.C.D. traits perfectly.

AJJ: Yeah, they couldn’t have dovetailed each other better. Especially with regard to the Old Testament, where most of the rituals are just that—rituals. I’d been practicing my own rituals for 37 years, these odd behaviors I’ve come up with, like touching the sink faucet four times. And here the Bible had provided me with these time-tested rituals with which I could replace my own.

BH: Are you calling Abraham and Moses obsessive-compulsives?

AJJ: [Laughing] I don’t know about that. Freud would certainly say they were.

BH: You also attended a meeting of New York City Atheists. What did that teach you about belief versus non-belief?

AJJ: I thought it was a paradoxical organization, because it struck me as difficult to rally around a lack of belief. It’s sort of like holding an apathy parade: what’s the point? And these people get together on Sunday, and all my non-believer friends became atheists partly because they didn’t want to get together on Sunday.

But if there was one thing I underestimated, it’s the new atheist movement. Non-believers have gathered a lot of steam lately, with the success of all these books. So if there’s one section I could go back and change in my book, it’s the part on atheism.

BH: Now that your yearlong project is finished, do you still follow any of the odder rules you had to observe?

AJJ: What do you mean, odder rules?

BH: Well, I assume you still adhere to the more common ones, like “Thou shalt not kill.”

AJJ: Ah, that is true. I have not returned to murdering. And, yeah, I stopped stoning adulterers, and I’ve gone back to wearing clothes made of mixed fibers. But there’s a huge number that have carried over. I love the Sabbath, and I try to observe it. This idea of a sacred day of rest in which you can reflect on the previous week is wonderful no matter what your beliefs are. I continue to say my prayers of thanks. The biblical idea of gratefulness has totally sunk in and changed me.

But I also made more minor changes. There’s a line in Ecclesiastes that says that “your garments should always be white,” and I decided to follow that literally. For most of the year, I still try to wear white.

BH: Really? Even after Labor Day?

AJJ: Even after Labor Day. There are no asterisks in the Bible.

BH: So, Mark Twain, Tom Wolfe, now A.J. Jacobs—three writers in white…

AJJ: Now that is good company. At one point in my project, I did sort of look like Tom Wolfe in white. Though more like Tom Wolfe of the first century. But again, it was a case of the outer affecting the inner. I felt happier wearing white clothes—more pure and spiritual—even if it was difficult to do in New York, where basically no one ever wears white.

BH: You started your project as an agnostic. Where did you end up?

AJJ: I became what a minister friend calls a “reverent agnostic.” I love the term, even though it sounds paradoxical. Whether or not there is a God, I believe in the idea of sacredness. How the Sabbath and our prayers and rituals can be sacred—hugely important parts of our lives. So I evolved in that sense.

BH: Does your alter ego, Jacob, still exist?

AJJ: Well, the enormous beard I grew still exists. I shaved it off but I kept it in a plastic Ziploc bag, because I felt that it had taken on a life of it’s own and become a member of the family. I keep offering souvenir tufts to people, but no one has accepted yet.

BH: I can’t imagine why.

AJJ: I know! It’s shocking. But if I were to think of Jacob metaphorically, then I’d say that, yes, I dropped my alter ego just like I shaved off the beard. And as with the beard, there will always be a shadow of him, maybe a three-day shadow. Because I think that the impact of this project was enormous on me, and it will always be there, even if I’m no longer dressing in robes and constructing biblical huts in my apartment.