THE investigation of the truth is in one way hard, in another
easy. An indication of this is found in the fact that no one is able
to attain the truth adequately, while, on the other hand, we do not
collectively fail, but every one says something true about the
nature of things, and while individually we contribute little or
nothing to the truth, by the union of all a considerable amount is
amassed. Therefore, since the truth seems to be like the proverbial
door, which no one can fail to hit, in this respect it must be easy,
but the fact that we can have a whole truth and not the particular
part we aim at shows the difficulty of it.

    Perhaps, too, as difficulties are of two kinds, the cause of the
present difficulty is not in the facts but in us. For as the eyes of
bats are to the blaze of day, so is the reason in our soul to the
things which are by nature most evident of all.

    It is just that we should be grateful, not only to those with
whose views we may agree, but also to those who have expressed more
superficial views; for these also contributed something, by developing
before us the powers of thought. It is true that if there had been
no Timotheus we should have been without much of our lyric poetry; but
if there had been no Phrynis there would have been no Timotheus. The
same holds good of those who have expressed views about the truth; for
from some thinkers we have inherited certain opinions, while the
others have been responsible for the appearance of the former.

    It is right also that philosophy should be called knowledge of the
truth. For the end of theoretical knowledge is truth, while that of
practical knowledge is action (for even if they consider how things
are, practical men do not study the eternal, but what is relative
and in the present). Now we do not know a truth without its cause; and
a thing has a quality in a higher degree than other things if in
virtue of it the similar quality belongs to the other things as well
(e.g. fire is the hottest of things; for it is the cause of the heat
of all other things); so that that causes derivative truths to be true
is most true. Hence the principles of eternal things must be always
most true (for they are not merely sometimes true, nor is there any
cause of their being, but they themselves are the cause of the being
of other things), so that as each thing is in respect of being, so
is it in respect of truth.