“I know” and “I already know this” are two phrases that seem to be everywhere. Try telling something to a teenager. If you get six words out before they snarl back with, “I know,” you’re lucky. No matter what you were about to tell them, it seems they were one step ahead of you. Like Kreskin, they know.

But it isn’t just teenagers. We adults “know” too – albeit, usually in a different way.

When we seek out new information we often come away feeling discouraged because we believe that, well, we already knew everything we just encountered. (Sound a bit familiar?) It seems there’s so little truly “new” information that it’s easy to shoot down teachers, writers and others who fail to “wow” us with information we’ve never encountered before. And yes, I’ve been guilty of this myself. But I wonder if we’re really being honest. Think about it.

How do you know when you know something? That sounds like a trick question, but it isn’t. At some point in the learning process we all come to a point where we’re certain we “know” what we’ve been trying to learn. My question is, where is that point? Is it when you understand something? Is it when you can pass a test on the subject? Is it when you can teach the subject yourself?

I think for most people the answer lies somewhere within those options. At some point things just “make sense” to us and we’re certain we now “know” it. This seems so obvious it’s hardly worth mentioning. But, in fact, it is critical to mention because there is an enormous difference between actually knowing something and just thinking that you do.

Here’s a better way to tell:

You actually know something when you start living like you know it. In other words, your behavior changes in such a way that an observer would say, “Now there goes someone who knows.”

Until that point, you’re just kidding yourself. You may understand. You may be able to pass a test. And you may be able to teach. But unless your behavior reflects your knowledge, you don’t have any knowledge. At best, you’re on the way to knowing (which is essential). But at worst, you simply go around proclaiming you do. It may feel good to think you know, but it doesn’t make it true.

So how do you know when you know something? It’s a question worth asking yourself. Even better, ask those around you if you’re living as if you know. The answer might surprise you.