Picture a picture of a dog. Not shining Lassie or Fido. Rather “man’s best friend” kicked and beaten, hounded and mutilated by another dog. By a rabid predator of its own kind. Dress them up both, the killer and the killed, in colorful costume. Keep that vivid in mind.

Now, imagine from whose hand, in what print, on which screen you would accept to see that picture. How could you not feel revulsion? Disgust? Sympathy? Outrage? You would avert your eyes, turn it off, walk away. You would reject the thing and shun its maker. Come down hard on whoever brought it before you.

And — be most soberly honest here — you would never give that picture to your children. Innocence, with its myths and compulsions, is a saving grace for humanity. Innocence itself serves to call out inhumanity of this sort. We are rescued by our children because they require us to rescue ourselves. We do not give them pictures like this because it would hurt them and hurt us. We protect their innocence because we live, rightly, in fear and wonder at the power they will soon have over the world. A great deal depends on their belief that no one would treat a dog that way. Including the life of the dog. Including the life of the child.

Now turn instead to another picture. A picture of a human being. This is not difficult in a world glutted by images. Go to the movies. Attend the endless internet parade. Open that time-bomb you still call a “phone.”

Here you do not walk off. You rush in. Your daily diet includes once, twice, or a hundred times the mundane moment in which one person, calm or enraged, appears to utterly destroy the body of another. Guns, bombs, crashes, falls; flailing fists as every by-standing object becomes an instrument of battery.

All Marveled up and made Disney like this, everything that you would not accept to see done to that dog? You take it in like air and water. Crowds mowed down by weapons of war or the slow-motion agony of a bullet to the heart. It’s all fodder for your idle chat. You still get a good night’s sleep.

And this is day in and day out your present to your kids. You reward them with it. They long and plead for it. It is a currency they share with their peers. Natural feelings you extend to dogs and perhaps to babies fall away. You don’t care because you feel safe from pictured mayhem wherever you go. In your home. Your car. At the mall. At school. You take those circulating pictures in. Like breath. In and out. In and out.

Now look me in the eye. You are not safe. This is your life’s blood. In the pennies, nickels, and dimes of years your children will come gunning. When you ask them “why?” they will answer “why not?”

And you really don’t understand what happened in El Paso? In Dayton? Yesterday and tomorrow? Even a dog is not that stupid.

Peter Alexander Meyers is the founding director of The Civic Inquirer, an organization designed to shift the course of everyday public disputes by identifying authentically civic interests and strengthening the voices that seek to sustain them. Dr. Meyers is Professor of American Studies at the Sorbonne Nouvelle in Paris.