In our notations there is indeed something
arbitrary, but this is not arbitrary, namely that if we
have determined anything arbitrarily, then something else
must be the case. (This results from the essence of
the notation.)
A particular method of symbolizing may be
unimportant, but it is always important that this is a
possible method of symbolizing. And this happens as a rule
in philosophy: The single thing proves over and over again to
be unimportant, but the possibility of every single thing
reveals something about the nature of the world.