David Harbour came to Philadelphia sporting a beard nearly worthy of a lumberjack and prepared to not reveal a single plot point of the new season of Stranger Things, which I think I’m still allowed to say takes place in the summer of 1985.

I came to meet him at the Rittenhouse Hotel on Tuesday armed with a lengthy list from Netflix of potential spoilers for the eight-episode third season that will premiere July 4. Let’s call them no-talking points.

It could have been awkward. But Harbour has given a lot of thought to the Duffer Brothers’ nostalgic sci-fi phenomenon, where he stars opposite Winona Ryder as Jim Hopper, the small-town sheriff and adoptive father of the mysteriously gifted Eleven (Millie Bobby Brown). So there was still plenty to talk about. (We never got to the beard, but it looks a bit like the one he’s sporting in promotional shots for Frankenstein’s Monster’s Monster, Frankenstein, a mockumentary for Netflix that will premiere July 16.)

Here, edited and condensed, is the spoiler-free interview:

What’s the truest vague thing, or the vaguest true thing, you can say about the new season?

One of the most profound things about the show in general, and it’s not even acting or writing or anything, is to watch these kids grow up in real time. That’s what I’m struck most by, like I remember Finn Wolfhard’s little fat face when [the show began]. And now he’s like a big old rock star with chiseled features.

(From left) Sadie Sink, Noah Schnapp, Millie Bobby Brown, Finn Wolfhard, and Caleb McLaughlin in a scene from the new season of Netflix's "Stranger Things," which will premiere July 4.
Courtesy of Netflix
(From left) Sadie Sink, Noah Schnapp, Millie Bobby Brown, Finn Wolfhard, and Caleb McLaughlin in a scene from the new season of Netflix's "Stranger Things," which will premiere July 4.

Television in general is, you become a commodity. The model is Gilligan’s Island. Gilligan 10 years later is always going to be on the island. He’s always going to be wearing a red shirt, he’s always going to be trying to get off the island. And I think the problem with a show about kids is that the kids are gonna grow up. And instead of having it be a problem, instead of having it be a liability, to acknowledge that, to make it a part of the fiber of the show, I think it’s very sophisticated and it’s very profound. So when I watch the show, I think I cry more deeply as a result of that than anything else. It’s the passage of time that is the truest villain of anyone’s life. It’s worse than any Demogorgon.

What’s it like to be an adult on a show set during a portion of your own childhood? Do you recognize this kind of free-range childhood from the ’80s?

Nowadays, everything’s recorded and everything’s documented and they can go look at your Facebook page or your Instagram page. And back then it was like you could really get lost. You and your friends could get lost in the woods and do weird stuff that nobody knew about. And I think there’s a sense of that in the show — kids really were able to be kids. Now, I think you have to be savvy. Even as a child, you have to understand the fact that you’re being recorded. I think that’s part of the larger nostalgia [surrounding the show] is this idea that we’re not being so watched.

You were successful enough before Stranger Things to be a recognizable face. But is this the role, do you think, that you’ll be most recognized for over the rest of your life?

No, I’ve got plenty of work in me. I’m only 44. I mean, my best days are ahead and I’m getting more sophisticated in my work. I continue to take acting class. I continue to get better. I set my sights very high. Anthony Hopkins didn’t play Hannibal Lecter until he was [in his 50s]. I think there’s so much more in me. This is what I’m known for now. It is what catapulted me and launched me.

The adults in Stranger Things could so easily have been like the ones in the Peanuts cartoons, where you just heard the adults as this wah-wah sound. But they’re not.

It’s perceived as a kids’ show. I think that’s the hook, that we have the kids front and center. But in terms of the show itself, I think the kids are a third of it. Then there’s a third of it that are the teens and a third that [is] the adults.

That was one of the difficult things about pitching the show. Networks wanted a show about kids. And the Duffers were like, we want a show about people. And only Netflix was able to go, all right, fine, you can do this whole thing.

I think there’s room to three-dimensionalize every character. And I think that’s one of the great things about the show. It’s just really good storytelling. They don’t talk down to the kids. They don’t characterize the kids as being dumb or not, [for] being interested in all sorts of weird stuff that I was interested in as a kid.

Is that what attracted you?

The character of Hopper is certainly as rich as any character I’ve ever been given. Like he is a throwback to these ’80s, rugged cowboy-like broken men that I grew up with, à la [Gene Hackman’s The French Connection detective] Popeye Doyle or any Nick Nolte role from the ’80s or Harrison Ford [as] Indiana Jones.

One of the things I really like about Hopper, one of the things I thought they’d maybe shy away from, is he’s very messy, to the point where his homophobia shows up in almost the first scene [of the series]. I think one of the reasons why he is adorable is because of the roughness in the beginning. That he was such a douche in the beginning makes the transformation of your love for him so much deeper.

David Harbour as Jim Hopper and Winona Ryder as Joyce Byers in a scene from the third season of Netflix's "Stranger Things."
Courtesy of Netflix
David Harbour as Jim Hopper and Winona Ryder as Joyce Byers in a scene from the third season of Netflix's "Stranger Things."
Did you grow up watching Winona Ryder?

Yeah. Totally.

I feel as if Millie Bobby Brown occupies a similar place in today’s culture. What are the two of them like as scene partners?

They’re both great, in very different ways. One of the most beautiful things about Winona is I really like to work in a personal way and sometimes that means messy. You have days where you don’t like each other very much. And we feed on these emotions that are very deep and these relationships are very deep.

[With Ryder] we can just go through things together. You can be mad at me for days for very personal things about me and I can fall in love with you for days for very personal things about you and we can just play with those things. And it doesn’t happen off screen, only when you shut the door to the set, so that it’s very respectful. Because the work is the work and then you leave the work and you go to your personal life.

Millie Bobby Brown (left) as Eleven and Sadie Sink as Max Mayfield in a scene from the new season of Netflix's "Stranger Things," which will premiere July 4.
Courtesy of Netflix
Millie Bobby Brown (left) as Eleven and Sadie Sink as Max Mayfield in a scene from the new season of Netflix's "Stranger Things," which will premiere July 4.

And with Millie, she’s technically very sophisticated, and she does things very well and I feel all the things that a father feels for her — I want what’s best for her. I am very protective of her. I worry about the culture of deification of her because when Meryl Streep was 12 years old, she wasn’t getting award nominations and I want her to be our Meryl Streep.

Stranger Things. Thursday, July 4, Netflix.