You’re reading a book when there is a knock on the door. You get up and walk to see who it is. You turn the deadbolt and put your hand on the doorknob. You open the door. On the other side, standing across the threshold, is your long lost brother. You have not seen him in years. You both stand there for a moment, looking at each other. He opens his arms to give you a hug. You hesitate before opening your arms to hug him back. You embrace. It has been ten years since you’ve seen each other and seeing his face is such a surprise.

Except, no it isn’t. Not really. It is just a scene in a play and you are only acting. You saw each other last night. And the night before and the night before that. Last weekend it happened, too. You rehearsed this moment every day in the three or four weeks before you opened the show. The last thing this moment is is a surprise. And yet it must be. It must be as if you have never gone through it before. This is the actor’s paradox.

Actors have a uniquely difficult challenge among artists. For our work to be good, we must possess the ability to both know and not know simultaneously. We have to live in this paradox, this human quantum state. There really isn’t another art form with such a requirement. It is unique to what we do.

Most of us just fake it. We pretend. We look at our friend, that actor playing our brother and we just put on the physical trappings of surprise. We open our mouth in pretend shock. We let out an audible gasp, just enough for the audience to hear it, because we want to show the audience how surprised we are. We need them to get it. For the story to be told, we telegraph the cliche of shock to the audience. We try to trick them away from seeing it isn’t really happening.

The trouble is, if you’re anything like me, fakery and trickery makes me immediately self-conscious. When I give in to pretending, it’s as if a giant blinking sign instantly manifests in front of my eyes, a sign that says in penetrating neon letters, “YOU LIAR!” My face gets hot and I fall into myself, ashamed and alone in my glaring dishonesty. I have let the audience down. I know that I have failed. And my work suffers. For the rest of the scene, I’m in my head thinking, “Did the audience just see me lying to them? Do they know?”

And the truth is, yes! The audience knows when we lie to them. Maybe not consciously, but, on some level, they always know! When actors fake it, even when they fake it well, the audience goes to sleep metaphorically and often literally. Sadder still, most audiences have grown accustomed to dishonesty and trickery. They’ll still clap and maybe even give a standing ovation at the end of untruthful performances. Out of politeness, they will settle for our lies. But they will leave with an aching suspicion that there could have been more in what they just watched, that there was something missing. And they are right.

We all know when we see truly great acting because it becomes invisible. Instead of a performance, we only see true life engendered before us. There is no pretending, there is only life itself. There is a knock on the door, it opens and the great actor actually is surprised.

But how? Why can some actors both know what is about to happen and not know simultaneously? Because some have learned, deep in their bones, that no moment will ever occur twice. No knock will ever really be the same as any other knock, no matter how many times it gets rehearsed. No matter how long you live, you will never repeat a single second of your life, onstage or off. Not really. The great actor accepts this truth and trains their attention on the specific miracle of each fleeting moment with such dexterity that they can not only see it unfold, but be fully in response to what is unfolding. They give up the futile, intellectual attempt to control and give over to the miracle of the temporary and all its potential.

This takes training and a process, but it is possible. Not only is it possible, it is necessary. Because in the presence of truly great acting, we can remember that nothing is pre-ordained, that we can each change the world, that we are alive. Great acting reminds us that this moment is the only one we will ever truly have.