Problem: About the topic of national debt, it just likes we borrow money from our offspring. Most of us think the debt is bad. However, someone has different ideas. If you can borrow some money from your children, you will be better off and your children will be worse off after that. But, if your children can also do the same thing to your grand children, they will be no longer worse off but your grand children will be worse off. Suppose human beings can exist forever and every generation could borrow money from their next generation. The first generation has more money and no one loss anything. Is that great? Who say there is no free lunch in the real world? What do you think about this idea?