To show the history of development of geological ideas in the context of the intellectual background of their times, to demonstrate how the scientific method works and how it is capable of correcting errors as demonstrated by abuses exemplified in hoaxes, swindles and fraud from three centuries. The Beringer case takes an example from the transition period between fantastic speculation about fossils and their origin, and the first systematic scientific theories based on comparative anatomy and basic geological principles. The diamond caper demonstrates Clarence King's application of new quantitative theories on metamorphism and mineral genesis as well as field observations to unravel a fraudulent scheme. The Piltdown man controversy centers around the application of quantitative laboratory methods to accurately determine ages of fossil remains. All three demonstrate how people will believe what they want to believe even in a purely scientific context, but where the scientific method applied rigorously and with integrity will lead to uncover scientific fraud.