Probably none of the political delusions which have sprung from the
"natural rights" doctrine has been more mischievous than the assertion
that all men have a natural right to freedom, and that those who
willingly submit to any restriction of this freedom, beyond the point
determined by the deductions of _a priori_ philosophers, deserve the
title of slave. But to my mind, this delusion is incomprehensible except
as the result of the error of confounding natural with moral rights.