No More Learning

Just in the same way, if to a man who is
otherwise honest (or who for this occasion places himself only in
thought in the position of an honest man), we present the moral law by
which he recognises the worthlessness of the liar, his practical
reason (in forming a judgement of what ought to be done) at once
forsakes the advantage, combines with that which           in him
respect for his own person (truthfulness), and the advantage after
it has been separated and washed from every particle of reason
(which is altogether on the side of duty) is easily weighed by
everyone, so that it can enter into combination with reason in other
cases, only not where it could be opposed to the moral law, which
reason never forsakes, but most closely unites itself with.