features are those
without which the proposition could not express its sense.

3.341 So what is essential in a proposition is what all propositions
that can express the same sense have in common. And similarly, in
general, what is essential in a symbol is what all symbols that can
serve the same purpose have in common.

3.3411 So one could say that the real name of an object was what all
symbols that signified it had in common. Thus, one by one, all kinds of
composition would prove to be unessential to a name.

3.342 Although there is something arbitrary in our notations, this much
is not arbitrary--that when we have determined one thing arbitrarily,
something else is necessarily the case. (This derives from the essence
of notation.)

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 this logical place is guaranteed by the mere existence of the
constituents--by the existence of the proposition with a sense.

3.41 The propositional sign with logical coordinates--that is the
logical place.

3.411 In geometry and logic alike a place is a possibility: something
can exist in it.

3.42 A proposition can determine only one place in logical space:
neverthele