There’s a certain class of bodily actions that I feel especially grateful for, and that I’ve been noticing more and more recently. I’ll call them unconscious subroutines—little functions, procedures, or actions that your brain and body carry out with next to no involvement from your conscious self.

I’m not talking about totally unconscious behaviors like your heartbeat, or the defenses of your immune system, although those are cool too. I’m talking about behaviors that are sort of at the boundary of the conscious and unconscious. Routines that your brain and body carry out without your help, but which, at the same time, are only executed at your command. It’s like your own personal assistant: a remarkably reliable and effective one, whose internal workings are a complete black box to you.

Here’s an example: remembering the digits of your phone number. Start enumerating the digits of your phone number in your head. Where are these digits coming from? You have no idea. It’s not like you have any conscious control over the numbers—your brain is reading them from somewhere that you don’t have access to. And yet, it reliably gives you the numbers whenever you ask for them. How convenient is that?

This kind of subroutine is happening all the time and is a pillar of our ability to function in the world. Every day you wake up knowing how to brush your teeth (as well as knowing that brushing your teeth is a thing you should do) and make your tea or breakfast. You know how to walk (which was something you actually had to learn at one point, but is now effortless to you). You know how to type in your password on your laptop or your passcode on your phone.

Your conscious life is filled to the brim with these unconscious—but voluntary—subroutines. And it’s only when you notice an interruption to them, or simply learn that it’s possible for them to stop functioning, that you really appreciate their power and utility. You, as a conscious agent, have no control over whether and how your brain will retrieve these things from memory—you just call upon them whenever you want and hope that your brain will oblige.

So if you’re lucky enough to be someone who’s able to move and act in the world—someone who’s able to carry out complex actions like walking, picking up objects, typing on a computer, or speaking words, all at your own will—you are unbelievably powerful and lucky. It doesn’t always work that easily.