When Ignorance Is Bliss

Whoa whoa whoa. Let’s not eat the fruit from that tree over there. The Big Guy said not to.

Knowledge always comes with a cost.

There’s the literal physical cost to process information, like the electricity needed to power a CPU, or the energy you need to fuel your brain—a fifth of the calories you eat goes there, in spite of making up only about a fiftieth of your weight.

With Maxwell’s Demon, this cost is made clear at a fundamental level:

The idea you have is to let only the cold atoms enter over on the right side, while only the hotter ones stay on the left side. After a while, you would start to see stragglers—fast particles on the right or slowpokes on the left. Each time you get the chance, when one of those particles is about to hit your wall in the middle, you just open that tiny portal.

This would create “free energy” from thin air, simply by sorting particles. There’s a fundamental problem, though:

It turns out that it costs energy to separate those particles. I’m not talking about whatever energy it takes to open and shut Maxwell’s Demon’s little trap door, but instead a different type of energy. This is the energy required to sort anything out, or to think about something.

These are measurable costs based on universal physical law. They are the undeniably real trade-offs between energy and knowledge, for knowledge is nothing more than information that has been sorted.

There’s another type of cost I want to talk about today. These are the times when simply not knowing something is better for you than knowing the thing.

Having to see something offensive to your sensibility is a good reason to avoid looking some things up, but it’s certainly not the only reason someone might want to avoid knowing something.

There’s also another type of pain that knowledge can bring you. Oppenheimer famously felt this when he saw the first atomic bomb detonated, and realized that the Faustian bargain that had just been unleashed onto the world could never be undone.

Then, there are spoilers. Not knowing the ending of a book or movie can make the suspense and mystery much more enjoyable, and some folks even take this desire so far as not to want to know when they’re going to die in real life. An inevitable fate might be better left to mystery, since otherwise you’ll just live in fear and anticipation.

Cautionary tales abound from human mythology. There’s The Odyssey with the beckoning Sirens, who sing hypnotizing songs that Odysseus insists on hearing while he’s tied to the mast. If he is exposed to this information, he’ll rush to certain death—but the mast keeps him safe.

This warning is most famously echoed in the classic story of the Garden of Eden, when the humans suddenly face the horrible reality that knowledge can bring suffering.

And then, there’s Odin.

I hung on that windy tree,
nine long nights,
wounded with a spear,
dedicated to Odin,
myself to myself,
on that tree of which no man knows
from where its roots run.
— Hávamál, stanza 138

Odin is hardcore. He knows full well that knowledge has a tremendous cost, and he willingly hangs himself from a tree, then stabs himself with his own spear. After going without food and water for nine days of suffering and self-sacrifice, he has the runes—the wisdom he is after.

I’m using wisdom and knowledge a bit interchangeably here, but you need knowledge in order to gain wisdom. Odin is after information that has been processed, but unlike Adam and Eve, he understands the cost before going through suffering. Like Odysseus, he understands that knowing has a cost.

What are you willing to sacrifice for knowledge? When is ignorance bliss for you, personally?