Several weeks ago, my daughter had night terror. They are aptly name. She was terrified and it was terrifying to watch. She screamed so hard she couldn’t cry and fought, trying to defend herself. After 5-7 minutes, she calmed down and slipped right back into sleep.

That night, I stayed awake, watching her and thinking. The next morning, she didn’t remember a thing. She went off about her day, happy as a bug. I, on the other hand, was pretty raw. Once I was able to step back, however, her display of what I can only call primal fear, and the empathic recognition I felt, struck me as interesting and made me think.

What is the nature of fear? I don’t mean what purpose does it serve. I mean what is it? At it’s most basic, fear is a response – a response to a perceived threat. It prompts our brains to produce chemicals that induce either flight or fight. This response is innate – people run at the feared object or they run away. Most people lean more heavily towards one or the other. Others have equal access to both. I’m a natural fighter. And that night, as my daughter pummeled away despite stress and obvious fear, she showed me that she is too.

In a film last year called After Earth, Will Smith portrayed a type of warrior who is, literally, without fear. This absence of fear renders him invisible to a species that marks its prey phenomenally. Fear smells good to them. To transcend fear, to somehow rise above and conquer an amygdala level response, is portrayed in the film as the ideal. In fact, the film’s climax centers around the young protagonist’s ability to do just that – eradicate his fear response and defeat the “monster” that was stalking him.  In the film, this ability signals both he attainment of an ideal, and the next level of development for human beings.

It’s a compelling message on the surface. Transcend your fear to the point of eradicating the response. Who wouldn’t want that? Upon consideration, however, I would say that, seductive though it is, it’s a bit of a misleading message.

In reality, fear serves two purposes. The first is obvious – that initial response – flight or fight – that might keep you from getting killed.

The second purpose, though less obvious, is arguably just as important. Fear keeps us civilized. Fear makes us aware of consequences. As in, Don’t jump off that building. You could break your neck, or Don’t rob that bank. You could end up in jail.

Granted, fear also adds an element of risk to those activities and others like them. Therefore, fear could be said to heighten the thrill of doing these things. But for most of us, on some level, fear is the filter that keeps us from being psychopaths. Fear reins us in.

In the end, After Earth implies that fear is a useless emotion – one that a person must transcend. I would argue that fear is neither salutary nor unsalutory. It’s a matter-of-fact response. It’s value correlates to the value of swallowing or blinking. It happens because that’s how our physiology evolved.

Simply put, you cannot choose not to fear. To suggest doing so is to suggest the physically improbable. What you can do, is manage the impulse. You can train yourself to acknowledge fear without attachment, as many Buddhists do. You can teach yourself to channel the adrenaline fear produces into defense. You can learn to dismiss, or channel, or transcend the response once you’ve had it. You can do many things with instinctive fear, but you cannot eradicate it. Realistically speaking, it’s part of our make-up. We might as well not breathe.

My daughter fought, even though she was terrified, even though she obviously didn’t know what was happening and that she wasn’t alone. She fought, and she fought hard. Fear told her to fight. Fear told her to survive. That’s the purpose of fear.

Evolutionarily speaking, fear has kept up from poking bears with sticks, and from eating the berries that killed Old Man Grog. Fear has kept us viable, even though predators with teeth and claws should have destroyed our tender, pink selves. Running. Fighting. That is what fear helps us do.

If the time comes to eradicate the fear response then we will – slowly, over millennia. In the meantime,  it might be more useful to understand fear, and how it functions. Better to accept and  live  comfortably with it, rather than wish, fruitlessly, that it didn’t exist.