The view expressed in the Tractatus Logico-Philosophicus of Wittgenstein, that a sentence must share a pictorial form with whatever state of affairs it reports. Wittgenstein was impressed by the way a model, for instance of a traffic accident, could be used to illustrate the actual events, and the picture theory takes the relationship of model to situation as the fundamental semantic relationship. It requires that elements of the model correspond to elements of the situation, and that the structure of the model is shared with that of the situation.