Before Darwin's evolutionary theory (in which all living things arise through descendants with modification), Linnaeus had proposed that species were immutable entities. Although it was an erroneous concept, this belief enabled the development of a system for classifying and naming organisms. Indeed, Linnaeus is nowadays recognized as the father of taxonomy to create this system. This example shows that scientific knowledge is not based on factual information, but it is a process that progressively increases our understanding of the real world.