There’s an objective reality, but our brains don’t see it.

It’s February 2014 and the internet is, as usual, embroiled in a heated argument. All around the globe, people boldly declare their opinions, only to have family, friends, and complete strangers aggressively dismiss them as delusional.

So what’s got the world all wound up? A simple picture of a blue-and-black dress. Or is it a gold-and-white dress? Well, that’s exactly the issue. Everyone’s looking at the same picture but seeing completely different things.

This optical illusion became a viral sensation because it revealed an uncomfortable truth about the human mind. It showed millions of people that what we think of as reality is just an interpretation.

The key message here is: There’s an objective reality, but our brains don’t see it.

The controversial color-changing dress isn’t the only example of how our brains' interpretation of some circumstance or other can differ from reality. In fact, distortions like this are extremely common. Just think of all the different optical illusions you’ve encountered throughout your life.

One popular example shows two circles, each surrounded by a different field of color. At first glance, the two circles appear different, with one clearly being darker than the other. But when you hold the shapes side by side, their shade is exactly the same. The variation only appears because your brain is interpreting the visual stimulus differently, depending on the surrounding context.

Want another example? This time, imagine sitting in a stationary train. As you gaze out the window, the train on the next track starts to move forward. For a brief second, as you see it glide away, you may feel as if you’re moving backward, even though you’re not moving at all.

Clearly, it’s not just your eyes that are vulnerable to deceit. All our senses can be tricked by the mind. But if all our senses are unreliable, how do we know what’s really real? Well, a lot of the time, we don’t. And that’s okay.

For the most part, distortions of the outside world are harmless, or even beneficial, because they let us concentrate on more important sensations, like pain or fear. And, because our brains are the result of millions of years of evolution, the way they interpret reality doesn't have to be accurate. It just has to help us survive.