I'm not sure that that is exactly Ricardos law. That applies more to trade and specialisation. The basic laws of supply and demand (price of labour will adjust

I'm not sure that that is exactly Ricardos law. That applies more to trade and specialisation. The basic laws of supply and demand (price of labour will adjust until all labour is employed) should theoretically be enough to cover it. But I don't find this to be sufficiently explanatory of what we observe in the world. For one thing, you would expect that the price of labour be extremely volatile, especially at the bottom, in response to technologically driven change. This is not the case. The price of labour tends to be stable and rises slowly across most categories at the bottom (though it does not necessarily keep pace with the economy). For another, in such a world one would expect the effects of minimum wage on employment levels to be easy to predict (like price restrictions on the consumption of goods and services). They are not. We can play games in the extreme margins (see what happens if you set minimum wage to $1000 p/h), but in the moderate ranges, the effects are usually pretty foggy. In any case, citing some fundamental economic principle is not what I meant when I said explanation. I meant at least to some idea of how the mechanics of that principle apply in this case. Labour is different to most inputs in that production of its raw materials is not really sensitive to prices or market forces,. It is, from the market's perspective, arbitrary.