Book I: On the Causes of Improvement in the Productive Powers. On Labour, and on the Order According to Which its' Produce is Naturally Distributed Among the Different Ranks of the People.
Adam Smith
The whole of the advantages and disadvantages of the different employments of labour and stock must, in the same neighbourhood, be either perfectly equal or continually tending to equality. If in the same neighbourhood, there was any employment evidently either more or less advantageous than the rest, so many people would crowd into it in the one case, and so many would desert it in the other, that its advantages would soon return to the level of other employments. This at least would be the case in a society where things were left to follow their natural course, where there was perfect liberty, and where every man was perfectly free both to choose what occupation he thought proper, and to change it as often as he thought proper. Every man's interest would prompt him to seek the advantageous, and to shun the disadvantageous employment.
Pecuniary wages and profit, indeed, are everywhere in Europe extremely different according to the different employments of labour and stock. But this difference arises partly from certain circumstances in the employments themselves, which, either really, or at least in the imaginations of men, make up for a small pecuniary gain in some, and counterbalance a great one in others; and partly from the policy of Europe, which nowhere leaves things at perfect liberty.
The particular consideration of those circumstances and of that policy will divide this chapter into two parts.
Part I: Inequalities arising from the Nature of the Employments themselves
Part II: Inequalities by the Policy of Europe