"I'm learning something"

This is the belief that makes the fill feel like a virtue. It's not noise. It's a history series. An interview with someone who knows things. You're using the walk to become a better-informed person, and a book that wants the walk back is a book against learning.

I'd separate input from what happens to input, because the fill supplies the first and prevents the second.

Benjamin Baird and colleagues, in 2012, gave people a creativity problem, then a break, and then the problem again. During the break, some did a demanding task, some an undemanding one, some rested, and some had no break. The people who'd done the undemanding task, the one that let the mind wander, improved most on the problems they'd already seen. Not the ones who rested, and not the ones who worked hard at something else. The undemanding stretch was where the incubation happened, and it was associated with more mind wandering, not with more deliberate thinking about the problem.

Now apply that to the podcast. You've heard an hour about the Byzantine Empire, and it was excellent, and then the next episode started, and then the radio, and then the audiobook. At no point was there an undemanding stretch in which the hour could do anything. It went in and the next thing went in on top of it, and what you have is a great deal of input and very little that's finished forming. Ask yourself what you remember from last month's episodes. In my experience the answer is the feeling of having learned something and not much of the something.

A field that's never left fallow is a fair comparison for two sentences. It takes seed every season, and it yields less each year, and the farmer wonders why.

Learning isn't only hearing. It's hearing and then having a walk in which the heard thing turns into a thought of your own, or doesn't, and the walk is where the fill goes. A person who listens to one episode and then walks in quiet has learned more from it than a person who listens to three, because the first person gave the episode somewhere to go. The method in chapter 21 keeps the podcast and moves it to a chosen time, and chapter 19 gives it the quiet stretch afterwards. That's not less learning. It's the half of learning you've been skipping.