My godchildren, who live next door to us this summer, have a young cat named Boo. Picture a soft, pale-gold fluffball with golden eyes, twining around my legs while I'm trying to water the plants. When I ignore him, he rolls and stretches on his back, purring. Boo is so friendly, he once followed my husband and godson on a walk along the river, dashing ahead of them on the trail and then lying down with paws in the air, begging a tummy rub. He's also made numerous attempts to enter the house, slipping through opened windows or doors on a great explore. And if I weren't terribly allergic to cats, I'd be tempted to keep him.
First it was a dead mouse in the yard. Then it was a baby bird. Then another. Then two more mice in various stages of...well, I won't go into it. One afternoon I found a baby bird on the ground, and while I was trying to figure out what to do Boo suddenly appeared and pounced on it. I shrieked. I threated the cat. I ran for the shovel, so I could lift the unconscious bird out of Boo's reach. I hollered for my husband to help me. Shaking his head he said, "Sarah, he's an animal."
Of course, my husband still helped me. But his words sunk in. This fluffy, adorable little personality was not a person. He was a small creature whose primary instincts were to hunt other small creatures. Boo was not capable of looking at the baby bird and saying, "Ooo, isn't it so cute?" or, "It is my duty to protect such a vulnerable little thing." He would never be able to rationalize himself out of a kill by saying, "Look, dude, you're not even hungry." This is why God did not put cats in charge of the world.
Not that fallen humans are doing much better. If anything, our ability to rationalize is precisely why our behavior is so much more sinister. We rationalize ourselves into doing things we know we shouldn't do. If it were simply a matter of instinct, we'd be no more guilty than Boo. This is why we need Jesus. Not because we are naturally, instinctively inclined to selfishness at others' expense. But because we are deliberately, calculatingly so.