%0 Journal Article %A Ayala, Francisco J. %T Darwin and the scientific method %D 2009 %R 10.1073/pnas.0901404106 %J Proceedings of the National Academy of Sciences %P 10033-10039 %V 106 %N Supplement 1 %X There is a contradiction between Darwin's methodology and how he described it for public consumption. Darwin claimed that he proceeded “on true Baconian [inductive] principles and without any theory collected facts on a wholesale scale.” He also wrote, “How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!” The scientific method includes 2 episodes. The first consists of formulating hypotheses; the second consists of experimentally testing them. What differentiates science from other knowledge is the second episode: subjecting hypotheses to empirical testing by observing whether or not predictions derived from a hypothesis are the case in relevant observations and experiments. A hypothesis is scientific only if it is consistent with some but not other possible states of affairs not yet observed, so that it is subject to the possibility of falsification by reference to experience. Darwin occupies an exalted place in the history of Western thought, deservedly receiving credit for the theory of evolution. In The Origin of Species, he laid out the evidence demonstrating the evolution of organisms. More important yet is that he discovered natural selection, the process that accounts for the adaptations of organisms and their complexity and diversification. Natural selection and other causal processes of evolution are investigated by formulating and testing hypotheses. Darwin advanced hypotheses in multiple fields, including geology, plant morphology and physiology, psychology, and evolution, and subjected them to severe empirical tests. %U https://www.pnas.org/content/pnas/106/Supplement_1/10033.full.pdf