The statement about the aggregate is meaningless without the materialised, individual transactions, because those are what determine the price. I think of it a

The statement about the aggregate is meaningless without the materialised, individual transactions, because those are what determine the price. I think of it as an order book where supply is the ask and demand is the bid. You can only argue that supply never meets demand if there's no liquidity, but that doesn't refute the "law".