Wittgenstein states that a proposition must be a picture of the situation that it describes no matter whether it exists or does not exist in the phenomenal world. Again, to know the sense of a proposition means to know the situation that it describes. In this regard, he says that just by looking at a proposition, I can tell what situation it describes. I can 'read off' from the proposition itself, even if the proposition is quite new to me and no one has explained its sense to me² (Pitcher, 1972,77). This is possible because for him, a proposition shows its sense but does not state its sense (Tractatus, 4.022). Thus, sense is the intrinsic property of a proposition.

In the picture theory of meaning it is stated that every proposition depicts a picture. Here, Wittgenstein does not mean the ordinary kind of picture, rather it is a 'logical picture' or the spatial picture of the situation that a proposition describes. In order to have a logical picture of a proposition it must satisfy three features. These are:

There must be one to one correspondence between the thing and its picture.
Every feature of the real object must be found with the picture of that object.
Components of real object must be same as the components of the picture of that object.

Since each proposition depicts a picture and the picture represents a situation what the proposition describes, from this it is asserted that every proposition represents a fact or a state of affairs of the world. In this sense, Wittgenstein expresses that a proposition is a model of the situation. Thus for him, "A proposition is a model of reality as we imagine it" (Tractatus, 4.01). But there are cases where propositions are constituted with proper names. In this case propositions do not describe the state of affairs of the world. So question arises, how can we claim that all the propositions are regarded as model of reality? Further, how is it possible that a series of mere names that are the constituent parts of a proposition can describe a fact or a state of affairs and how can this sort of proposition be treated as either true or false?

Wittgenstein replies that one name stands for one thing, another for another thing, and they are combined with one another. In this way the whole group- like a tableau vivant - presents a state of affairs (Tractatus, 4.0311). In addition to this, he states that only acts can express a sense, a set of names cannot (Tractatus, 3.142).

Here, the question arises, how is it that a picture represents a situation? Wittgenstein answers that what constitutes a picture is that its elements are related to one another in a different way (Tractatus, 2.14). A picture is a fact because the fact that the elements of a picture are related to one another in a determinate way represents that things are related to one another in a same way (Tractatus, 2.15). Hence, each picture represents a situation that the proposition describes.

²	This is explained in Tractatus, 4.021.