Empirical evaluation has for many years been utilised to validate theories in other science disciplines. One of the first well-known reported examples of empirical evaluation occurred when Galileo wanted to prove that the rate of descent of objects was independent of their mass. This would disprove a theory put forward by Aristotle that the rate of descent is directly proportional to their weight. To prove his theory Galileo dropped two balls made from the same material but different masses from the top of the Tower of Pisa. When the experiment was performed Galileo's theory was proved correct through the empirical evidence collected. What this story demonstrates is the importance of empirical validation to verify or disprove theories and hypotheses. The purpose of this chapter is to emphasise the importance and difficulties of empirical evaluation in the domain of SPLE.
In addition to physics, experimentation plays a vital role in other disciplines. For example, medicine as a discipline did not really exist before experimentation was applied to this area (Basili, 1996). Instead, remedies and cures to illnesses were passed around based on hearsay, or from generation to generation. When experimentation was applied to medicine real progress was observed, with extra resources diverted to areas showing promise. Applying experimentation can speed up the progress of a discipline by quickly eliminating futile approaches and incorrect theories. Furthermore, experimentation can potentially open up new areas of research by uncovering unexpected results.