I don't agree. Instead of being between two people, think of the transaction as being between a person and society. Since society offers a lot of different thin

I don't agree. Instead of being between two people, think of the transaction as being between a person and society. Since society offers a lot of different things, you can sell your pigs to society for a token which you can later use to redeem goods and services later. In this sense money is a debt - or an IOU - from society to the holder.