Naturalism can be described as the approach that maintains, starting from the fact that human knowledge is a human process, that cognitive problems are psychophysiological processes. Naturalism starts from the assumption that knowledge is a function of the human animal that is just as natural as any other function. Although naturalism came to prominence in the epistemology of the second half of the 20th century, it is possible to trace it back to Aristotle, insofar as we consider knowledge a psycho-physical process of the human being (Blasco & Grimaltos, 1997, pp. 23–34).