In this article, we present a discussion on the role of graphs and its significance in the relation between the number of initial conditions and the order of a linear differential equation, which is known as the initial value problem. We propose to make a functional framework for the use of graphs that intends to broaden the explanations of the traditional analytical frames that are widely favoured in school mathematics. As a result, the different forms and functions of graphs support their redefinition in a specific situation of the initial conditions. To that end, graphs are presented as a means to explore the nature of differential equations; thus, considering an epistemology based on the uses of graphs to explain the construction of mathematical knowledge.