In philosophy, praxeology or praxiology (ˌpɹæksiˈɒlədʒi; ) is the theory of human action, based on the notion that humans engage in purposeful behavior, contrary to reflexive behavior and other unintentional behavior.
French social philosopher Alfred Espinas gave the term its modern meaning, and praxeology was developed independently by two principal groups: the Austrian school, led by Ludwig von Mises, and the Polish school, led by Tadeusz Kotarbiński.
Coinage of the word praxeology (praxéologie) is often credited to Louis Bourdeau, the French author of a classification of the sciences, which he published in his Théorie des sciences: Plan de Science intégrale in 1882:
On account of their dual natures of specialty and generality, these functions should be the subject of a separate science. Some of its parts have been studied for a long time, because this kind of research, in which man could be the main subject, has always presented the greatest interest. Physiology, hygiene, medicine, psychology, animal history, human history, political economy, morality, etc. represent fragments of a science that we would like to establish, but as fragments scattered and uncoordinated have remained until now only parts of particular sciences. They should be joined together and made whole in order to highlight the order of the whole and its unity. Now you have a science, so far unnamed, which we propose to call Praxeology (from πραξις, action), or by referring to the influence of the environment, Mesology (from μεσος, environment).
However, the term was used at least once previously (with a slight spelling difference), in 1608, by Clemens Timpler in his Philosophiae practicae systema methodicum:
There was Aretology: Following that Praxiology: which is the second part of the Ethics, in general, commenting on the actions of the moral virtues.
It was later mentioned by Robert Flint in 1904 in a review of Bourdeau's Théorie des sciences.
The modern definition of the word was first given by Alfred V.