Slavery, if it can be legalized at all, can be legalized only by positive legislation. Natural law gives it no aid. Custom imparts to it no legal sanction.
Interpretation
The quote argues that slavery can only be justified through law, not by morality or tradition.
Lysander Spooner emphasizes that slavery cannot be supported by natural law or custom; instead, any legal justification for slavery must come from explicit positive legislation. This reflects a philosophical stance on the moral implications of law versus the laws enacted by society, suggesting that legality does not equate to morality.
In practice
In a debate about human rights, one might reference this quote to argue against unjust laws.
The principle that the majority have a right to rule the minority, practically resolves all government into a mere contest between two bodies of men, as to which of them shall be masters, and which of them slaves; a contest, that-however bloody-can, in the nature of things, never be finally closed, so long as man refuses to be a slave.
For a government to declare a vice to be a crime, and to punish it as such, is an attempt to falsify the very nature of things. It is as absurd as it would be to declare truth to be falsehood, or falsehood truth.
And the men who loan money to governments, so called, for the purpose of enabling the latter to rob, enslave, and murder their people, are among the greatest villains that the world has ever seen. And they as much deserve to be hunted and killed (if they cannot otherwise be got rid of) as any slave traders, robbers, or pirates that ever lived.
A married woman has the same natural right to acquire and hold property, and to make all contracts that she is mentally competent to make reasonably, as has a married man, or any other man.
Those who deny the right of a jury to protect an individual in resisting an unjust law of the government, deny him all defence whatsoever against oppression.
There is not, in the Constitution, a syllable that implies that persons, born within the territorial limits of the United States, have allegiance imposed upon them on account of their birth in the country, or that they will be judged by any different rule, on the subject of treason, than persons of foreign birth.
Global terrorism is extreme both in its lack of realistic goals and in its cynical exploitation of the vulnerability of complex systems.
Nothing is built on stone; all is built on sand, but we must build as if the sand were stone.
And then he drew a dial from his poke, And looking with lack-lustre eye, Says very wisely, 'It is ten o'clock: Thus we may see', Quoth he, 'how the world wags: 'Tis but an hour ago since it was nine, And after one hour more 'twill be eleven; And so from hour to hour we ripe and ripe, And then from hour to hour we rot and rot.
Wherever politics tries to be redemptive, it is promising too much. Where it wishes to do the work of God, it becomes not divine, but demonic.
The way up and the way down are one and the same.
He, then, that would really, thoroughly, and acceptably mortify any disquieting lust, let him take care to be equally diligent in all parts of obedience, and know that every lust, every omission of duty, is burdensome to God, though but one is so to him.
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