What is solitude? If you are alone in a forest reading a book, miles away from any other humans, is that solitude?

No, it is not. Cal Newport's book Digital Minimalism is where I learned this.

The key to solitude is being isolated from the output of other minds. When you're alone in the forest, there aren't any people physically in your vicinity, but the author of the book you're reading is very much influencing your thoughts.

Think about it: imagine if the author was sitting next to you in the forest on a bench telling you about their thoughts on, I don't know, congestion pricing. How different is that from them writing a book about congestion pricing and you reading it? In both scenarios you are basically consuming the outputs of this author's mind.

Lesson #1: The right way to define “solitude” is as a subjective state in which you’re isolated from input from other minds.
When we think of solitude, we typically imagine physical isolation (a remote cabin or mountain top), making it a concept that we can easily push aside as romantic and impractical. But as this book makes clear, the real key to solitude is to step away from reacting to the output of other minds: be it listening to a podcast, scanning social media, reading a book, watching TV or holding an actual conversation. It’s time for your mind to be alone with your mind — regardless of what’s going on around you.

— Spend More Time Alone

Ok, so now that we understand what solitude is, let's talk about its importance.^[1]

To me at least, it's not obvious that solitude is an important thing to experience. I might even go as far as saying that I find it to be counterintuitive.

Fast food? Smoking? Lack of sleep? Stress? Sure. I get why all of those things are bad for you. But solitude? Is it really that big a deal that you listen to music on your way home from work and then watch TV the rest of the night before going to sleep?

Well, here's what Cal Newport has to say:

Lesson #2: Regular doses of solitude are crucial for the effective and resilient functioning of your brain. 
Spending time isolated from other minds is what allows you to process and regulate complex emotions. It’s the only time you can refine the principles on which you can build a life of character. It’s what allows you to crack hard problems, and is often necessary for creative insight. If you avoid time alone with your brain your mental life will be much more fragile and much less productive.

But this just speaks to the more emotional benefits of solitude. Solitude is also helpful for knowledge work. Here's Cal Newport again:

Exceptional things — be it ideas, writing, mathematics, or art — require hard work. This, in turn, requires boring stretches during which you ignore a mind pleading with you to seek novel stimuli — “Maybe there’s an e-mail waiting that holds some exciting news! Go check!”

— Have We Lost Our Tolerance For a Little Boredom?

Newport has a chapter in his book Deep Work that discusses this sort of stuff in more detail. There's also this blog post of his that quotes writer Neil Gaiman's advice:

“I think it’s about where ideas come from, they come from day dreaming, from drifting, that moment when you’re just sitting there…”

“The trouble with these days is that it’s really hard to get bored. I have 2.4 million people on Twitter who will entertain me at any moment…it’s really hard to get bored.”

“I’m much better at putting my phone away, going for boring walks, actually trying to find the space to get bored in. That’s what I’ve started saying to people who say ‘I want to be a writer,” I say ‘great, get bored.'”

And in Childhoods of exceptional people, the author finds that immersion in boredom was a universal experience:

But this immersion in boredom is also a universal in the biographies of exceptional people. A substantial fraction were completely kept apart from other children, either because their guardians decided so or because they were bedridden with various illnesses during childhood (like Descartes). A spicy hypothesis raised by this is that socializing too much with children is simply not good for your intellectual development. (I’m not going to test that hypothesis!)

None of this is an airtight argument that solitude is in fact important, but hopefully it at least is intriguing.

Ok, now let's talk about podcasts. I feel like podcasts are the solitude killer. Well, things like social media and Netflix are also pretty big solitude killers. I guess I'll propose that podcasts are a solitude killer. Or maybe that, for a certain type of person, they are on the shortlist of biggest solitude killers.

I find myself listening to a lot of podcasts. I'll listen to them when I'm walking my dog, commuting, cooking, cleaning, eating, doing chores, going to sleep, and sometimes even when I'm... gasp... coding! With the exception of coding, I think these are, for the most part, all great opportunities to get some of that cherished solitude time. And I don't think I'm alone in my experience of having podcasts eat in to this potential solitude time.

So, when, if ever, is it appropriate to listen to podcasts? I think my feelings here are similar to my feelings about carbs.

Personally, I eat way too many carbs. In most situations, I don't endorse myself eating more of them. One exception that comes to mind is if the food is particularly delicious; in that case I could see the hedonic benefits outweighing the costs. Another exception is perhaps if I need the energy boost for a long bike ride or something. But in the large majority of situations, I don't want to eat more carbs.

Now, I could imagine a world where this is not true. I could imagine a world where my diet is different and doesn't have a (large) surplus of carbs. In that world, I'd be a lot more open to fitting more carbs into my diet.

It's similar with podcasts and solitude. My "diet" currently has way too little solitude and boredom in it. And given this current diet, I don't really see much room for podcasts to be incorporated. If my diet was different then maybe it'd make sense for podcasts to play more of a role, but I don't see my diet being different any time soon.^[2]

Similar to food diets, if the podcast is "yummy" enough, perhaps it'd be worth making an exception. Perhaps the benefits outweigh the costs.

Similar to food diets, if I "need the nutrients", it also might be worth making an exception. A good example of this, I think, is listening to podcasts instead of nonfiction books.

Nonfiction books are typically around 300 pages because that's what sells, and to hit 300 pages, authors often need to add a lot of fluff.^[3] Like, to improve sales, a book that would otherwise be 120 pages will have fluff added to it until it grows to 300 pages. And for marketing stuff, authors will often go on these tours where they appear as guests on various podcasts. The interviews are usually around 60 minutes long and I find that they often serve as an 80/20 version of the book itself. So yeah, I think this is a notable exception of when it makes sense to listen to podcasts.^[4]

Similar to food diets, I don't want to overgeneralize here. I recognize that there are people who truly do have room for more carbs in their diets, both literal carbs and figurative carbs. In first world countries in 2025 I get the sense that this is somewhat rare, but it's probably common enough to be worth noting.

1. ^{^}

   Well, there's probably some more nuance when it comes to the question of what solitude is. It sounds like Newport has a preferred definition that a lot of other people agree with, but where there isn't universal agreement.
   
   I'll also note that, using Newport's definition, solitude exists along a spectrum. While listening to music you might not be influenced too heavily by the output of the artists mind, so maybe you're getting like an 8/10 level of solitude there.

2. ^{^}

   Maybe one day there will be something analogous to GLP-1 agonists like Ozempic to help improve our metaphorical "solitude diets".

3. ^{^}

   I recall hearing this in various places, including the website for the book Rework. I can't easily find any references though. This seems to indicate that the website for Rework is no longer up.

4. ^{^}

   I'm noticing that writing is probably a fantastic way to experience solitude. When you're writing, you're usually "spending time with your own mind" and are not dealing with the outputs of other minds. Well, I guess it depends how much research is needed.