Reason has to do with the rational mind, how we explain our actions or why we think we do what we do. The cause is what actually produces the effect, result or consequence. Reason implies thought while cause implies movement, the creation of a result. In some cases reason and cause can be synonyms. For example if my thoughts (reason) lead me to take a certain action, then that reason was the cause of my actions. In this example they are pointing out the differences between why we think we do something (reason) and what actually makes us do it (cause).