Free The Complete Aristotle (eng.) by Aristotle Page B

adopt a
certain course, a certain result would follow, while, if we did
not, the result would not follow. For a man may predict an event
ten thousand years beforehand, and another may predict the reverse;
that which was truly predicted at the moment in the past will of
necessity take place in the fullness of time.
    Further, it makes no difference whether people have or have not
actually made the contradictory statements. For it is manifest that
the circumstances are not influenced by the fact of an affirmation
or denial on the part of anyone. For events will not take place or
fail to take place because it was stated that they would or would
not take place, nor is this any more the case if the prediction
dates back ten thousand years or any other space of time.
Wherefore, if through all time the nature of things was so
constituted that a prediction about an event was true, then through
all time it was necessary that that should find fulfillment; and
with regard to all events, circumstances have always been such that
their occurrence is a matter of necessity. For that of which
someone has said truly that it will be, cannot fail to take place;
and of that which takes place, it was always true to say that it
would be.
    Yet this view leads to an impossible conclusion; for we see that
both deliberation and action are causative with regard to the
future, and that, to speak more generally, in those things which
are not continuously actual there is potentiality in either
direction. Such things may either be or not be; events also
therefore may either take place or not take place. There are many
obvious instances of this. It is possible that this coat may be cut
in half, and yet it may not be cut in half, but wear out first. In
the same way, it is possible that it should not be cut in half;
unless this were so, it would not be possible that it should wear
out first. So it is therefore with all other events which possess
this kind of potentiality. It is therefore plain that it is not of
necessity that everything is or takes place; but in some instances
there are real alternatives, in which case the affirmation is no
more true and no more false than the denial; while some exhibit a
predisposition and general tendency in one direction or the other,
and yet can issue in the opposite direction by exception.
    Now that which is must needs be when it is, and that which is
not must needs not be when it is not. Yet it cannot be said without
qualification that all existence and non-existence is the outcome
of necessity. For there is a difference between saying that that
which is, when it is, must needs be, and simply saying that all
that is must needs be, and similarly in the case of that which is
not. In the case, also, of two contradictory propositions this
holds good. Everything must either be or not be, whether in the
present or in the future, but it is not always possible to
distinguish and state determinately which of these alternatives
must necessarily come about.
    Let me illustrate. A sea-fight must either take place to-morrow
or not, but it is not necessary that it should take place
to-morrow, neither is it necessary that it should not take place,
yet it is necessary that it either should or should not take place
to-morrow. Since propositions correspond with facts, it is evident
that when in future events there is a real alternative, and a
potentiality in contrary directions, the corresponding affirmation
and denial have the same character.
    This is the case with regard to that which is not always
existent or not always nonexistent. One of the two propositions in
such instances must be true and the other false, but we cannot say
determinately that this or that is false, but must leave the
alternative undecided. One may indeed be more likely to be true
than the other, but it cannot be either actually true or actually
false. It is therefore plain that it is not necessary that of an
affirmation and a denial one should be true and the other