erit by virtue of my own power and the other contractor's
need, in the case of the gift, I merit only by the benignity of the
giver, and to the extent that, when he has given it, it shall be mine
rather than another's. This distinction he believes to coincide with
the scholastic separation of _merilum congrui_ and _merilum condigni_.

He adds many more particulars in regard to covenants made on mutual
trust. They are void in the state of nature, upon any reasonable
suspicion; but when there is a common power to compel observance, and
thus no more room for fear, they are valid. Even when fear makes them
invalid it must have arisen after they were made, else it should have
kept them from being made. Transference of a right implies
transference, as far as may be, of the means to its enjoyment. With
beasts there is no covenant, because no proper mutual understanding.
With God also none, except through special revelation, or with his
lieutenant in his name. Anything vowed contrary to the law of nature is
vowed in vain; if the thing vowed is commanded by the law of nature,
the law, not the vow, binds. Covenants are of things possible and
future. Men are freed from them by performance, or forgiveness, which
is restitution of liberty. He pronounces covenants extorted by fear to
be binding alike in the state of mere nature and in commonwealths, if
once entered into. A former covenant makes void a later. Any covenant
not to defend one's self from force by force is always void; as said
above, there is no transference possible of right to defend one's self
from death, wounds, imprisonment, &c. So no man is obliged to accuse
himself, or generally to give testimony where from the nature of the
case it may be presumed to be corrupted. Accusation upon torture is not
to be reputed as testimony. At the close he remarks upon oaths. He
finds in human nature two imaginable helps to strengthen the force of
words, otherwise too weak to insure the performance of covenants. One
of these--_pride_ in appearing not to need to break one's word, he
supposes too rare to be presumed upon. The other, _fear_, has reference
either to power of spirits invisible, or of men. In the state of
nature, it is the first kind of fear--a man's religion--that keeps him
to his promises. An oath is therefore swearing to perform by the God a
man fears. But to the obligation itself it adds nothing.

Of the other Laws of Nature, treated in Chap. XV., the third, _that men