But their ability
to know is denied by those who maintain that it is
not certain what the future will be. Now don't
you see what doubtful premises they assume to be
certain and take for granted? Next they hurl this
dialectical dart: 'Therefore it is not true both that
there are gods and yet that they do not give signs
of the future.' And of course they think that the
matter is now settled. Then they make another
assumption: 'But there are gods.' Even that is
not conceded by everybody. 'Therefore they give
signs of the future.' Not necessarily so: for they
may not give us signs of the future and still be gods.
'Nor is it true that, if they give such signs, they give
no means of interpreting those signs.' But it may
be that they have the means and yet do not impart
them to man; for why would they impart them to
the Etruscans rather than to the Romans? Again,
the Stoics say: ' If the gods do impart the means,
that is divination.' Grant that they do (which is
absurd), what is the good if we do not understand?
Their conclusion is: ' Therefore there is divination.'
Suppose that is their conclusion, still they have not
proved it; for, as they themselves have taught us,
the truth cannot be proved from false premises.
Hence their entire argument falls to the ground.