Edmund Gettier called into question the theory of knowledge and the traditional definition of knowledge. Gettier's argument is that there are situations in which one's belief may be justified and true, yet fail to count as knowledge. He contended that while justified belief in a true proposition is necessary for that proposition to be known, it is not sufficient. According to Gettier, there are certain circumstances in which one does not have knowledge, even when all of the above conditions are met. Gettier proposed two thought experiments, which have come to be known as "Gettier cases," as counter examples to the classical account of knowledge. He argued it is possible to arrive at an assumption based on belief which is deemed justified, but happens to be true only by chance, because the outcome was predicted for the wrong reason and so can't be classed to be knowledge.
Empirical research often begins with a question such as: Does talking on a phone impair driving ability? From this initial question, a hypothesis for research can be proposed: Speaking on a cell phone will impair driving . That hypothesis can then be tested by examining primary data gathered by the researcher for that particular study or existing secondary data that has already been gathered by others. For example, empirical data might be gathered from correlating police records or speaking to a representative of the police department as primary research or from examining previously compiled studies as secondary research . From the gathered data, it can be decided if the hypothesis is supported or not and work towards the conclusion.