from a state of captivity in war; whence slaves are called _mancipia,
quasi manu capti_. The conqueror, say the civilians, had a right to
the life of his captive; and, having spared that, has a right to deal
with him as he pleases. But it is an untrue position, when taken
generally, that, by the law of nature or nations, a man may kill his
enemy: he has only a right to kill him, in particular cases; in cases
of absolute necessity, for self-defence; and it is plain this absolute
necessity did not subsist, since the victor did not actually kill him,
but made him prisoner. War is itself justifiable only on principles of
self-preservation; and therefore it gives no other right over
prisoners, but merely to disable them from doing harm to us, by
confining their persons: much less can it give a right to kill,
torture, abuse, plunder, or even to enslave, an enemy, when the war is
over. Since therefore the right of _making_ slaves by captivity,
depends on a supposed right of slaughter, that foundation failing, the
consequence drawn from it must fail likewise. But, secondly, it is
said that slavery may begin "_jure civili_;" when one man sells
himself to another. This, if only meant of contracts to serve or work
for another, is very just: but when applied to strict slavery, in the
sense of the laws of old Rome or modern Barbary, is also impossible.
Every sale implies a price, a _quid pro quo_, an equivalent given to
the seller in lieu of what he transfers to the buyer: but what
equivalent can be given for life, and liberty, both of which (in
absolute slavery) are held to be in the master's disposal? His
property also, the very price he seems to receive, devolves _ipso
facto_ to his master, the instant he becomes his slave. In this case
therefore the buyer gives nothing, and the seller receives nothing: of
what validity then can a sale be, which destroys the very principles
upon which all sales are founded? Lastly, we are told, that besides
these two ways by which slaves "_fiunt_," or are acquired, they may
also be hereditary: "_servi nascuntur_;" the children of acquired
slaves are, _jure naturae_, by a negative kind of birthright, slaves
also. But this being built on the two former rights must fall together
with them. If neither captivity, nor the sale of oneself, can by the
law of nature and reason, reduce the parent to slavery, much less can
it reduce the offspring.

[Footnote a: pag. 123.]

[Footnote b: _Servi aut fiunt,