.. if a person’s rights consist primarily, not in moral facts about the rights-bearer, but in moral facts about other people, then the rights-bearer cannot simply dispose of his or her rights. You cannot, by a simple act of will, release me from my obligation not to coerce you, since that obligation depends on my calling as a human being, something that is not in your control. Hence, on the supply-side conception of justice, no one can divest him or herself of the right not to be coerced. In short, the right to liberty is inalienable.
In forbidding A to sell him or herself into slavery (or, more broadly, any kind of indentured servitude) to B, then, we do not in any way infringe upon A’s liberty; for what A is offering to do is to transfer to B the right of decision over A’s life and actions; but in fact this right cannot be transferred, as it is not under A’s control. Thus A’s offer to sell this right is fraudulent; A is trying to sell something that is not hers to sell.
One objection that is sometimes raised against the defenders of inalienability is this: If slavery contracts are impermissible, how can any room be made for ordinary contractual obligation? ..
.. contracts can legitimately be “enforced” in the sense that a person who has received some consideration in exchange for an unperformed service can be required to pay back the consideration. Even “slavery contracts” could be enforced in that sense; for example, if, in exchange for 2000 drakhmas, I agree to do whatever you want, for the rest of my life, then if I ever back out of the contract (which I am free to do at any time), I have to pay you 2000 drakhmas (plus damages) — but I may not legitimately be forced to fulfill the contract. (If I do not presently have the money to pay, then I simply have a debt, like any other.)
.. nothing can release us from our obligation to behave like human beings toward one another, rather than like animals. Our classical liberal forebears fought a long hard battle against slavery, that disgrace upon human civilization. Two centuries ago, a newborn Free Nation’s compromise with slavery started it down the path that eventually destroyed its freedom. As for our future, a Free Nation that undertook to enforce slavery contracts would not be a Free Nation worth fighting to build or to defend.