Interest is essentially the price of trust and liquidity (which is very similar !).
Why do I need a "loan" ? What is a loan in fact ? It is the exchange of a promise of mine against "money", which I will use to buy something ; say, a car. Now why would the car salesman not accept my promise, but accept money ? Because the car salesman has more trust in the money system than in me ; which indirectly means, that he has more trust in the issuer of the money (and in all people trusting this), than in me directly. Note that the car salesman can perfectly accept my own promise, and doesn't need me to go getting a loan ! If I buy a car on credit directly with the car salesman, I have in fact short-circuited the lending circuit of money. But in many cases, I need money and I can't buy it with my promise directly, because my promise is trusted less than money from a bank.
When I exchange a promise (to pay back) against money, I exchange a "low value trust" asset (my promise) against a "high value trust" asset (money). The interest is the price I have to pay to the detainer of "trust" to use his trust. His trusted issuing of money has more trust (and hence liquidity - no discussions to be had, everybody accepts it) than my issuing of promises ; so me exchanging my promise for his money is what I need to pay with interest.
The free market sets this interest rate. In as much as I think that in the end, his trust is over-rated, and the car salesman will accept my promise directly (direct credit with the car salesman !), I don't take his high-interest loan. In as much as I really depend on his trusted money and nobody accepts my promises directly, I'm obliged to accept high interest.
In fact, the whole fiat system is based upon a layered system of trust like this, where money is issued on a higher layer (central bank, say) is issued against promises of higher quality down to promises issued by individuals against loans.
I think that's a great way of stating it.
The author spoke of the theory of "time-value" and also "risk", as two reasons for interest. He says time-value is non-sense:
There is no ‘time value’ of money. It is all created by bookkeeping and the bank loses nothing. It creates the money when lending and retires it when repaid. But even when we talk about savings, there is no real ‘time value’.
Of course for banks printing money that may be true. For people with savings, afaics, he's saying the fact we're saving means we're not presently using, therefore can lend to somebody who will use.
Because why do people save? To use it later! They don’t want to use it now, otherwise they would not save! So they lose absolutely zero by not being able to use it now if they lend it out. Not using it now but later is the essence of saving! And if we are not going to use it now, why not let somebody else use it in the mean time??
What are your thoughts on that? Personally, there are many things I could do with my money. Invest it real estate, stocks or businesses, where I'd earn ROI or receive equity for example. Why would I lend it for nothing? (exceptions being those close to me)
To me his interest free credit idea is a niche. I'd like to see it be successful, but I have my doubts of it becoming very large. It would be nice to see, as I think there would be greater accountability when dealing with already established relationships vs large faceless banks.
Are you familiar with Ripple? I think the Ripple network sort of technologically represents this network of trust idea, although I don't understand Ripple that well. I know that you can extend certain amounts of trust (credit) to people, who in turn trust others.