# The Metaphysics of Physics Part IV: Calculation

In this video we begin our journey into the final tool that underpins the scientific method and that is mathematics. Our ultimate aim over the next few videos is to prove the famous Einsteinian equation Energy=mc^{2}. In order to do this we are going to build our mathematical tool from the ground up starting with the basic operands of addition, subtraction multiplication and division. To use a skiing analogy, this is like a green ski run in that we are beginning our mathematical journey using basic mathematical techniques that we first learnt when we were children.

Yet even on these gentle slopes of basic arithmetic, we shall discover that the alignment of mathematics to the universe it ultimately describes is not always that straight forward; in particular, we shall see that common mathematical concepts like a negative number and zero still require some careful thought in understanding what component of our reality they are actually describing, let alone what is the meaning of infinity in a reality which appears to us to be finite.