1. A DISTINCTION BETWEEN THEORY AND LAW

This is a common question, and a common misconception. Unfortunately, most people are taught a hierarchy of certainty: hypothesis becomes theory and then, with more support, a theory becomes law. This notion is wrong. Laws and theories serve different purposes and each have a unique nature.

The current consensus among philosophers of science seems to be this:

Theories are explanations of observations (or of laws). The fact that we have a pretty good understanding of how stars explode doesn't necessarily mean we could predict the next supernova; we have a theory but not a law.

Laws are generalizations about what has happened, from which we can generalize about what we expect to happen. Laws describe. They pertain to observational data. The ability of the ancients to predict eclipses had nothing to do with whether they knew just how they happened; they had a law but not a theory.

William McComus lists gravity as a modern example of a well-established law for which no really satisfying theory is available. We can use the Law of Gravity, and even correct it for the effects of relativity (General Relativity), but we don't have any consensus notion of how it functions.

1b. WHY IS THE LAW OF DEMAND AND SUPPLY CALLED LAW?

The common sense principle or law that defines the generally observed relationship between demand, supply, and prices: as demand increases the price goes up, which attracts new suppliers who increase the supply bringing the price back to normal. In microeconomics, supply and demand is an economic principle of price determination in a market. It concludes that in a competitive market, the unit price for a particular good will vary until it settles at a point where the quantity demanded by consumers (at current price) will equal the quantity supplied by producers (at current price), resulting in an economic