According to Wittgenstein, "There must be something identical in a picture and what it depicts to enable the one to be a picture of the other at all". "What a picture must have in common with reality, in order to be able to depict it- correctly or incorrectly- in the way it does, is its pictorial form" (Tractatus, 2.161, 2.17). Here, Wittgenstein states that there must exist one-to-one relation between the elements of a picture and the objects of a fact on the ground that each fact depicts a picture. On this consideration, it is asserted that since each proposition depicts a picture it states about the objects of the reality. Further he states that "the elements of the picture must be capable of some combination with each other in a pattern corresponding to the relationship of the elements of what is pictured" (Kennay, 1973, 57). From this it is understood that every picture represents a possible state of affairs and it refers to the existence and non-existence of objects of the world. A picture will be considered true if it agrees with the reality and false if it does not agree with the reality. A proposition which depicts a picture can neither be affirmed as true nor as false unless it pictures the reality. It is so because it is the elementary proposition which describes about the reality presented in a pictorial form to claim that whether the proposition is true or false. Hence, all elementary propositions can be treated as either true or false on the basis of their logical pictures. It is pointed out that the sense of a proposition is same as the thought of a proposition. This is because the thought of a proposition states about the facts or state of affairs of the world. The proposition is true, if the thought which is expressed by the proposition corresponds to the facts of the world and if it does not correspond to the facts of the world then it is false. Hence, thought is the logical picture of a fact.

A question is raised here, if a picture is a combination of elements then what are the elements of a thought? Wittgenstein replies, "I don't know what are the constituents of a thought are, but I know that it must have such constituents which correspond to the words of language" (Kennay, 1973, 58). Further, he states that only possible states of affairs can be thought of. The totality of true thoughts is the picture of the world. Since any picture needs to be compared with reality to tell whether it is correct or not, there cannot be a thought whose truth is recognizable from the thought itself. Hence, no thought can be considered as an apriori truth (Tractatus, 3.01-3.05). Thought is a bridge which links between the propositions on one hand, and the states of affairs on the other hand. Thus, all the propositions are essentially either true or false.