3.3421 A particular mode of signifying may be unimportant but it is always
important that it is a possible mode of signifying. And that is generally
so in philosophy: again and again the individual case turns out to be
unimportant, but the possibility of each individual case discloses
something about the essence of the world.


3.343 Definitions are rules for translating from one language into another.
Any correct sign-language must be translatable into any other in accordance
with such rules: it is this that they all have in common.


3.344 What signifies in a symbol is what is common to all the symbols that
the rules of logical syntax allow us to substitute for it.


3.3441 For instance, we can express what is common to all notations for
truth-functions in the following way: they have in common that, for
example, the notation that uses 'Pp' ('not p') and 'p C g' ('p or g') can
be substituted for any of them. (This serves to characterize the way in
which something general can be disclosed by the possibility of a specific
notation.)


3.3442 Nor does analysis resolve the sign for a complex in an arbitrary
way, so that it would have a different resolution every time that it was
incorporated in a different proposition.


3.4 A proposition determines a place in logical space. The existence of