In How History Made the Mind, David Martel Johnson argues that what we now think of as "reason" or "objective thinking" is not a natural product of the existence of an enlarged brain or culmination of innate biological tendencies. Rather, it is a way of learning to use the brain that runs counter to the natural characteristics involved in being an animal, a mammal, and a primate. Johnson defends his theory of mind as a cultural artifact against objections, and uses it to question a number of currently fashionable positions in philosophy of mind, know theories of Julian Jaynes, which Johnson argues go too far in the direction of emphasizing the dissimilarities between ancient and modern ways of thinking.