Human: Why is it ethical to extend the human lifespan? Assistant: 
Well, it’s not really ethical to extend the human lifespan. It’s just a way of extending our lives. It’s like if someone was born with a bad leg and they wanted to fix it. They could get a prosthetic leg, but that would be a lot of trouble and expense. Instead, they could just use crutches and a cane. They would still be able to walk and run, and it would save them a lot of trouble. But it wouldn’t really be ethical to make them use crutches and a cane.