For example, we could find after study that there are no beachward currents in the area. As an example, I could propose that a dolphin happened to swim by, see Tom in trouble, swim underneath him then flick his tail and cast him up on shore - certainly less likely than our wave hypothesis. Nature of proof. Conversely , we CAN prove an idea to be wrong since it only takes one case to show that a hypothesis is not true. To take advantage of the ability to disprove hypotheses, we often state them as a null hypothesis - that is, we state that there is no difference between what we expected and what we found.
Biology has few laws.
In practice, there is no clear distinction between law, theory and hypothesis. Thus, biology is a statistical science. Generalizations in biology are probabilistic - because there are often exceptions. For more information, see the article, Duffy, D.C. 1990. Land of Milk and Poison.