What Is Debt?

What is debt exactly? It's money that i guess needs to be paid. What are some of the good things that this debt system does? So, without going into the entire history of currency and money as we know it, one time they used pepper cords. And until 19 64, these silver certificates, legally could be redeemed for the amount of silver that was mentioned on the currency. They were redeemable for same amount of a different material.