prehended in another manner, if any
contradictory statement is advanced; that is to say, just by way of
example, if, to continue arguing from the previous case, it can be
shown that the horse did come to one by inheritance, or if it should
not be discreditable to admit the last alternative, as if a person,
when his adversaries said,--"You were either laying an ambush against
the owner, or you were influenced by a friend, or you were carried
away by covetousness," were to confess that he was complying with the
entreaties of his friend.

But a simple conclusion is reprehended if that which follows does not
appear of necessity to cohere with that which has gone before. For
this very proposition, "If he breathes, he is alive," "If it is day,
it is light," is a proposition of such a nature that the latter
statement appears of necessity to cohere with the preceding one. But
this inference, "If she is his mother, she loves him," "If he has ever
done wrong, he will never be chastised," ought to be reprehended in
such a manner as to show that the latter proposition does not of
necessity cohere with the former.

Inferences of this kind, and all other unavoidable conclusions, and
indeed all argumentation whatever, and its reprehension too, contains
some greater power and has a more extensive operation than is here
explained. But the knowledge of this system is such that it cannot
be added to any portion of this art, not that it does of itself
separately stand in need of a long time, and of deep and arduous
consideration. Wherefore those things shall be explained by us at
another time, and when we are dealing with another subject, if
opportunity be afforded us. At present we ought to be contented with
these precepts of the rhetoricians given for the use of orators. When,
therefore, any one of these points which are assumed is not granted,
the whole statement is invalidated by these means.

XLVII. But when, though these things are admitted, a conclusion is
not derived from them, we must consider these points too, whether any
other conclusion is obtained, or whether anything else is meant, in
this way,--If, when any one says that he is gone to the army, and any
one chooses to use this mode of arguing against him, "If you had come
to the army you would have been seen by the military tribunes, but you
were not seen by them, therefore you did not go to the army." On this
case, when you have admitted the proposition, and the assumptio