需要と供給
If we mistakenly confuse precision with accuracy, then we might be misled into thinking that an explanation expressed in precise mathematical or graphical terms is somehow more rigorous or useful than one that takes into account particulars of history, institutions or business strategy. This is not the case. Therefore, it is important not to put too much confidence in the apparent precision of supply and demand graphs. Supply and demand analysis is a useful precisely formulated conceptual tool that clever people have devised to help us gain an abstract understanding of a complex world. It does not—nor should it be expected to—give us in addition an accurate and complete description of any particular real world market.