Learning to Debate, and the Invincible Dilema

"I don't understand why. You said that if you get a cut on your head, it bleeds a lot, right?" Hannah asked.
"Yes," I replied, recalling bringing Caleb to the hospital when he cut his head, my own stitches as a child, other head wounds I've seen.
"Well, why don't we have scales or something to make our heads not bleed so much. Why did we develop this way?"
"I don't know. Humans are an imperfect design."
Hannah sighed. "If I designed people, heads would be better."
"If I designed people, we'd be invincible," Caleb informed us, supremely confident in his assessment of what would solve all of our head-bleeding problems.
"That wouldn't be fun," Hannah opined. "If we were invincible...where would the conflicts be? Conflicts make life interesting."
"Sometimes...." I began.
"I don't mean wars," she said, obviously sensing "mom lecture mode" coming on. "I mean like if you were invincible, you wouldn't be afraid of car accidents or plane crashes, or anything so you'd never have conflict."
"I can see that," I admitted.
Caleb sounded hurt when he said, "Well, I guess I won't say anything else, since you both agree. Invincibility is bad I guess."
"No," I disagreed. "I never said that. Now you tell me what is so great about being invincible."
"Oh." Caleb warmed to his subject quickly. "You could do anything, you wouldn't worry about dying."
Hannah interrupted. "Then we'd have overpopulation," she said primly.
"Hannah, let Caleb have his turn," I said sternly. "Go on, Cay."
"No, people would die," he informed us. "But only of old age. Not from being sick, or accidents. We could climb mountains and not worry about falling off. We could survive crashes and we could do things that we don't do because we're afraid."
"Well, if I knew I wouldn't die from a fall, I might actually take up mountain climbing."
The kids laughed. They know I fear heights like nothing else.
"But if there's no danger, there's no conflict," Hannah said after a minute. "That wouldn't be interesting. You couldn't tell stories. Everyone would be the same. There wouldn't be any heroes."
"But people wouldn't die too young," Caleb countered. "You wouldn't need heroes. Everyone would be doing interesting things."
"Then no one would want to hear about it," Hannah stated. "Like a two year old could climb Mount Everest. It's just not interesting anymore."
Caleb laughed. "Or a grandma could jump out of planes."
"Not interesting."
"But safe. People could live longer."

I could see the points both were making.

I wonder if the presidential debates will be this interesting...or this civil.