3.21 The configuration of objects in a situation corresponds to the
configuration of simple signs in the propositional sign.


3.221 Objects can only be named. Signs are their representatives. I can
only speak about them: I cannot put them into words. Propositions can only
say how things are, not what they are.


3.23 The requirement that simple signs be possible is the requirement that
sense be determinate.


3.24 A proposition about a complex stands in an internal relation to a
proposition about a constituent of the complex. A complex can be given only
by its description, which will be right or wrong. A proposition that
mentions a complex will not be nonsensical, if the complex does not exits,
but simply false. When a propositional element signifies a complex, this
can be seen from an indeterminateness in the propositions in which it
occurs. In such cases we know that the proposition leaves something
undetermined. (In fact the notation for generality contains a prototype.)
The contraction of a symbol for a complex into a simple symbol can be
expressed in a definition.


3.25 A proposition cannot be dissected any further by means of a
definition: it is a primitive sign.