Honest question: Without interest ("usury"), how do you handle the time value of money? Am I (as an individual or a small bank) allowed to give you $$ today so that you can spend it on something you need now? If so, how am I to be compensated for my delayed spending, if not with more money in return at a later date? If you don't like that, let me give you an alternative abstraction: Let's say I have 5 gallons of gas and you need to go someplace today. I -could- go someplace today, but I could also wait and go next week. Yes, I'd like to use the 5 gallons today, but my schedule is flexible. Am I allowed to loan you the 5 gallons of gas? Would it be reasonable for me to expect you to give me 6 gallons of gas back next week given I deferred my travel? (If you are not willing pay me back with extra gas, and if you are not attractive enough to compensate me via means, then I'm not going to loan you the gas today.) (Fuck the central banks and their dirty pay masters. I'm not defending them. Just challenging you on the basic concept of the time value of money...)