Methodological dualism is an epistemological position which holds that it is necessary, based on our current levels of knowledge and understanding, to utilize a different methodology in our attempts to analyze the actions of human beings than the methodology used in the physical sciences (i.e. physics, biology etc...) to study external events. This position is based on the presupposition that humans differ fundamentally from other objects in the external world in that humans act, or in other words use and choose means to achieve their subjectively chosen ends, while other objects in nature, such as stones, planets, molecules and atoms do not. Furthermore, we do not at present know how external events affect an individual's "thoughts, ideas, and judgements of value" and this ignorance forces us to adopt a dualistic approach to the two classes of phenomena.
This view was emphasized by Ludwig von Mises and formed the central basis of his epistemology. Methodological dualism, especially in Mises's case, was a reaction to the notion held by groups such as the logical positivists that the study of human action, and as such economics, should utilize the same experimental scientific method as the physical sciences, a view that has been referred to by Mises, Friedrich Hayek and others as scientism. The alternative methodology that Mises developed and utilized for his study of human action was praxeology, which formed the basis for his work in economics. Praxeology differs from the mainstream neoclassical approach to economics, in that the mainstream approach utilizes the same overall methodology as the physical sciences in an attempt to develop economic theories and predict future economic.