You have probably “known your colors” since the day you started pointing to the sky and grass and calling out, “blue!” and “green!” But do you know your colors, really?

The world contains an infinite amount of colors. People can see about 1000 levels of light and dark. Multiply that by the 100 levels they see between red and green. Times that by the 100 levels they see between yellow and blue. That already adds up to 10 million colors!

And that doesn’t count viewing conditions. A color in a painting can look different based on what colors surround it or what kind of surface sits beneath it. It can even appear different based on the way someone sees.

But it’s not just the amount of colors that makes them hard to pin down. People just aren’t good at remembering them. Imagine a person walking into a room. She looks at the color of the wall. When she walks into the next room, someone shows her a series of colors like the wall she saw before. But she cannot tell which one matches. She doesn’t just have a bad memory. Everyone else would have the same problem. They would have to hold the colors up to the wall and compare.

In music, certain people have a gift called “perfect pitch.” That means they can remember a single note for a long time. If you say, “Sing me a C-sharp!” they will know just which note to hum. They won’t have to hear it on the piano first. But no one—not even a great artist—has that gift for color. People can only remember lots of colors if they compare them to other colors nearby.

In a sense, no human knows his or her colors—at least not all of them. No one but God ever could!