If we let everyone decide for themselves how they were best fit to benefit humanity, with no restrictions at all, how could they possibly end up with a distribution of labor more inefficient than the one we already have? This is a powerful argument for human freedom. Most of us like to talk about freedom in the abstract, even claim that it's the most important thing for anyone to fight or die for, but we don't think a lot about what being free or practicing freedom might actually mean.