There's a new documentary series on Netflix called Inside Bill's Brain. Whatever you think of the Microsoft co-founder, there are few things on this earth as fascinating as Bill Gates's brain. It not only created the most ubiquitous piece of computer software in existence but also the company that twice has become the most valuable on the planet.

Oh, and that brain mainstreamed the idea that those who've benefited greatly should use that benefit for the good of society. Like, for real. Give the guy credit for not only committing to give away at least half of his Microsoft fortune but also recruiting dozens of other billionaires to do the same with theirs. That's a lot going on in one brain.

But, believe it or not, this column isn't about how great Bill Gates is, and it's not about the three-part documentary (though it's an interesting watch if you have a few hours). Instead, it's about that brain, and the thing Bill Gates says is his greatest fear. 

"I don't want my brain to stop working," Gates tells us in the first two minutes of the film, which was directed by Oscar-winner Davis Guggenheim.

I'm sure to some extent Gates means that in the literal sense that everyone can relate to. No one really wants their brain to stop working, and there is no shortage of human conditions, like Alzheimer's, that could lead to the diminishment of one's brain functioning. And maybe that's entirely what he meant. 

But I think there is something a little deeper, and it's something worth paying attention to. In fact, I think it's the thing every entrepreneur should be afraid of.

That's because there are certainly moments when it would be easier to stop working on new things, to stick with one idea and see how far it will take you. But at some point, you have to ask yourself, if your brain isn't "working"--if you aren't using it productively--what are you really doing? I think that's something we should all fear. 

And the good news is that while modern medicine hasn't yet found a way to prevent our brains from eventually failing, whether or not it's working is entirely up to you. 

Learn

According to one of Gates's former employees at Microsoft, it wasn't uncommon for Gates to read as many as 14 books while he was on vacation. That same employee goes on to add that Gates reads upwards of 150 pages an hour. Most of us aren't blessed with the ability to read that fast or retain that much, but that doesn't mean you can't focus your mind on learning new things.

There are plenty of recommended reading lists if you're looking for a place to start, though books aren't the only way to learn. You can take an online course and learn about something new. It doesn't have to be directly related to your business or role: Learning to play an instrument or speak a new language will challenge you and open your mind. Some of the greatest ideas come from the combination of inspiration and information, regardless of the source. 

Practice

Another important way to keep your brain working is to get better at the thing you do. Whether you build things, dream of new ideas, or lead a team, practice can help you do it better. 

It's easy to dismiss this, especially because most of us barely have time for all of the tasks on our lists, but there's an interesting benefit to practice. Practice creates patterns and motor memory, which means that as you get better at something, you actually devote less thought to it. It becomes automatic, which means you have time to do new things. 

Innovate

While Gates is one of the most famous inventors of his generation, many of the greatest legacies he'll be remembered for involve finding a better way to do something important. For example, the documentary talks about one of the Gates Foundation's projects to bring toilets to impoverished communities where people are dying of completely preventable diseases that spread from bacteria that live in human waste. 

Toilets aren't exciting, but in an area without plumbing or electricity, you have to create a new way to do something that the rest of us take for granted. You might not be building a better toilet, but one of the best ways of keeping your brain working is to ask yourself "how can this thing be better?" 

The answer doesn't have to be complicated, but we need Bill Gates's brain, and your brain, and a whole lot of other brains working on these problems. If we don't, that's something to be afraid of indeed. 

Published on: Sep 23, 2019
The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.