I'm sorry but that's nonsense. People draw graphs all the times to prove things w/o using data. Especially when trends are what is important to convey in a grap

I'm sorry but that's nonsense. People draw graphs all the times to prove things w/o using data. Especially when trends are what is important to convey in a graphical sense. It's not any different then supply/demand curves for different types of goods in economics. The graphs represent a concise way of stating assumptions upon which the argument is based.