Last night living legend Paul Schrader brought his stunning First Reformed to the Independent Film Festival Boston. Starring Ethan Hawke as a pastor struggling with his faith, the movie feels like a culmination of the obsessions with which this filmmaker has been wrestling onscreen for more than four decades. Some edited highlights from his Q&A moderated by critic Jason Gorber:

Once you are raised in the bosom of the church that implanting never leaves you. No matter how far you think you’ve run from it, look over your shoulder and you’ll find it coming back again. This film was sort of a full circle. It’s been fifty years now since I left Calvin College and went to UCLA Film School, and this was the film that I swore I would never make.

I had written a book about spirituality in cinema [Transcendental Style In Film: Ozu, Bresson, Dreyer (1972)] which is being reissued this month by UC Press in an updated edition. But whenever anyone suggested that perhaps my films were related to that book, I would say “No, that’s not me. I’m not that guy. I’m not interested in making that film. I’m not gonna go skating on that Bressonian ice. I’m too intoxicated with empathy and sex and melodrama, so I’m not gonna go there.”

And then about three years ago I was giving Pawel Pawlikowski an award at the New York Society of Film Critics and he had done this film Ida, a Polish film about a nun. We got to talking about spiritual films, spiritual style. And I walked back uptown and said “Okay, it’s time. It’s time to write that movie you swore you would never write.”

There’s fingerprints all over it. You could almost do a footnoted, asterisked version. You have the main character from [Diary Of A] Country Priest, you have the setting from Winter Light, the ending comes from Ordet. There’s a little bit of Silent Light in there, a little bit of Ida in there. Of course there’s a Tarkovsky scene — the levitation scene, which was kind of Tarkovsky’s go-to position whenever he got two people horizontally. And then it’s all glued together with Taxi Driver.

I was in the editing room and the editor said to me, “There’s a lot of Taxi Driver in this film.” I said, “Yeah I knew there was some, but now watching as we’re editing there’s much more than I thought there was!” One of the reasons the film feels so fruitful to me is because it does combine that first book I wrote about spirituality in cinema and the first film I wrote, which is about the psychopathology of suicidal glory. I kind of combined them together here.

I had written Taxi Driver as a bit of self-therapy, because I was in a very bad place. I wrote it to get this character out of my life. Then I ended up coming back to L.A., back reviewing again. I was interviewing De Palma, because I had just done a review of Sisters. We started playing chess, and I said “Brian, you know I wrote a script once?” He said, “No! Don’t tell me! Don’t tell me you wrote a script!” I gave it to Brian, and he gave it to Marty. He said to him, “This is not for me but I think it’s for you.” So that’s how that connection started.

Taxi Driver is the story of someone obsessed with suicidal glory. Blood is in the DNA of Christianity. It keeps coming back: in the blood, washed in the blood, there’s a fountain filled with blood, dipped in the hands of blood. When Christian kids start to go crazy it’s not at all unusual that they go this way. They go into this notion that God demands my sacrifice, that if I’m washed in my own blood Jesus will accept me as one of his own and I will be transfigured.

Now this is obviously an insidious fantasy. It’s also a jihadist fantasy. It’s not much different than the Muslim kid who has that same fantasy. Christians have been having it for thousands of years. The scourgings, the whippings, the self-degradation that Christians do out of the notion that this will make them look better in God’s eyes. And Jesus doesn’t say that! That’s an aberrational mythology, but it is built into the DNA of Christianity. Christianity can be jihadistic just as easily as Islam.

I will never have to face the dilemma that motivates this movie: is it proper to bring a child into what the next fifty years will bring? But I’m not optimistic. I think we’ve made our decision [about global warming] and I think it’s too late to do much about it, other than exercise different levels of denial. There is a new world coming and your grandchildren will probably live to experience it. [The film] is hopeful that we can still have these ecstatic connections with the unknown, but that’s a whole other discussion than what is going to happen to our material lives.

I had not planned to move the camera. We made many rules for this film: you’re not gonna tilt or pan, you’re gonna delay your cuts, you’re not gonna have music, all kinds of things. And the nice thing about making rules is you get to break them. But you only break them to remind the audience that the rules are there. Then you go back. So I don’t move the camera, I don’t move the camera, then there’s that one odd shot where there’s a lateral dolly as they walk back to the garage and it’s like WHAT WAS THAT? That’s the intuitive part of filmmaking. I remember being on location that day and saying to the cinematographer, “I think today we break the rule. This shot right here. I’m not quite sure why but we’re gonna break the rule now.”

Something inside you gets anxious. Ethan is a good example. I explained to Ethan that this is a lean-back performance. You give the audience nothing. You just keep leaning away from them. And the more they lean towards you, the more you lean away, until finally you’re way in the back of your chair and they’re halfway across the table. Every reading must be flat. So then we were shooting a scene towards the end and Ethan starts crying, which is something we hadn’t discussed. He came back to me and he said, “I know I promised never to do that, but I just felt this morning that now was the moment to do it and I’ll go back and I’ll do it again straight if you want.”

I said, “Ethan, it was in your bones. You made the right choice.” How do those things happen? That’s the mystery of the creative process. You can’t overthink it. That’s the danger of also being a critic. I always say a critic is like a medical examiner. He wants to get that corpse on the table, open it up and find out how and why it lived or died. A filmmaker is like a pregnant woman. She just wants this thing to come out alive. If you let the critic into the birthing room, it will kill that baby.

There’s a trick I use in this film that I’ve used in Taxi Driver and other films. You deprive the viewer of any point of view but one. I call it a monocular vision. You have no idea what is happening in the outside world, you only know what your main character is doing and thinking. There’s no other perspective. He insinuates his way into your skin, often through narration, and you begin to feel his presence. And then he starts to veer off. After about forty-five minutes or an hour he starts to go, and the person you had deeply identified with slowly becomes a person that you no longer think is worthy of your identification.

What do you do? For the most part, you’re trapped. Because you’ve already bought into the identification and you want to see it out. You want to see how this is gonna happen. Once you get an audience to identify with someone they then regard unworthy of identification, you create a kind of chasm in their consciousness where all sorts of thoughts, feelings, emotions can creep in, and you as a filmmaker can’t even control them. At that point their head is just starting to split open.

Let’s put it this way, I hope this is not my last film. But if it is, it’s a very good last film.

Paul Schrader’s First Reformed opens in May.