Ricardo's difficult ideas

This is perhaps the best article that I have read so far in this semester.
Many interesting ideas and good advice on people to contemplate things.

Three implications underlie the Ricardian Model
(1)Wages are determined in a national labor market
The model envisages that a single factor, labor, can move freely between industries.
Wages earned in one industry are largely determined by the wages similar workers are earning in other industries.

Question: why does the author say that wages are endogenous?

(2)Constant employment is a reasonable approximation
International trade is a long run issue  tendency to return to full employment
Question: Is it possible? Isn't it contradict to Hazlett's idea in Economics in one lesson?

Central banks: stabilize employment

(3)The balance of payment isn't a problem
David Hume: trade imbalances are self-correcting. A surplus country will acquire specie, leading to rising prices that price its goods of world markets while a deficit country will find its goods increasingly comparatively priced.

Ricardian Model is an ideal model, the reason why it's rebuffed is that the world is complex and different countries may adopt mixed economy strategies.

Another interesting part of this article is that it gives us some advice on how to think like an economist. I find it useful because I am now doing my writing assignment and these pieces of advice are really good, which I can use to conclude my essay.

The similarties between capitalism and Ricardian Model is that both of them face a lot of objection and some reasons may be the same:
(1)People blame the problems caused by other kinds of systems on them
(2)There are too many variables that cause the same phenomena, but people just neglect other causes.
(3)Mixed economy stymie the effect of these systems
(4) People are prone to be fooled by fallacies, which are easier to understand
(5) Data are sometimes confusing.