Hello everyone, welcome to the Minescape Podcast. I'm your host, Sean Carroll.

And I wanted to tell you, those of you who have not already heard it, a little anecdote about one of the ways in which in a very tiny manner, I have influenced popular culture myself.

You may have heard of the movie Avengers Endgame. You probably have heard of it. It's the highest-grossing movie of all time.

And in that movie, a prominent role is played by the idea of time travel. So I'm not going to give away any spoilers for the movie, but there was a previous movie, Infinity War, in which bad things happened, and the heroes in Endgame want to fix those bad things by going to the past.

So when you want to have time travel in your movie, you have to make some choices about how it works. You know, we haven't seen time travel in the real world, so there's different theories of how it could possibly happen.

And at one point, Paul Rudd, who is the actor playing Scott Lang, aka Ant-Man, he and everyone else are talking about the ideas of time travel, and Paul Rudd says, so you're telling me that back to the future is just bullshit.

And I was actually serving as a science advisor for Endgame. Many people did. I was not the only one, but I remember I was in a room with the writers, the directors, the producers, and we were talking about the idea of time travel.

Time being one of my areas of expertise purportedly as a physicist, and I explained why I had bad feelings about back to the future, why I thought it was illogical, and so forth.

And so one of the people in the room said, you're telling me back to the future is just bullshit, and I agreed. And so that line appeared in the movie, I think I helped that line come into existence in a very tiny way.

And I think for the most part, Endgame did a good job at time travel. It was a little bit hazy on this idea of whether or not you can affect the past by going into it, but it was much more respectable and logical than something like back to the future would be.

But you know, I always, it always bothered me a little bit that line, because I have an attitude, a philosophy of how you should approach being a science advisor on movies.

You know, it's easy to get a bad reputation in Hollywood as a scientist. If all you do is hear what they want to do in the movie and say, no, you can't do that, right?

There are plenty of scientists who are very happy to join the writers and directors and tell them that they can't do that. They don't really need extra people doing that.

So my attitude is when you get a screenplay or a detailed outline that already exists and you're the science advisor, your job is not to scold them or tell them why they're wrong or give them a bad grade, okay?

Your job is to help them, your job is to serve the movie, tell the best, most interesting story it possibly can.

And the way that I find is helpful to sort of mentally line yourself to that job, that responsibility is to think of the screenplay as data rather than as a theory.

In other words, you're not looking at the screenplay and going, no, I don't think that's the way it would work. I don't think that's an accurate description of reality.

That's a bad attitude to have to a screenplay.

The screenplay is in this world what actually did happen. And so a scientist who gets data, gets an experimental result and whose response is, no, that can't happen is not going to get that far, right?

Once you shift your mental orientation from explaining what can and cannot happen to, oh, this is what happened.

Now my job to come up with an explanation for it, it frees your mind quite a bit and it's almost always possible to come up with explanations of how things can happen.

So in my mind, a movie that would be the greatest challenge to turn into something logical would be something like back to the future and it's sort of time travel, let's just say it was a little freewheeling when it came to the logic of time travel, which is actually admitted by the writers of the movie.

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