In the long-run the workman may be as necessary to his master as his master is to him, but the necessity is not so immediate.
Adam SmithThe difference between the most dissimilar characters, between a philosopher and a common street porter, for example, seems to arise not so much from nature, as from habit, custom, and education.
Adam SmithIt appears, accordingly, from the experience of all ages and nations, I believe, that the work done by freemen comes cheaper in the end than that performed by slaves.
Adam Smith