In Ancient Greek the word praxis (π, , ρ, , ᾱ, , ξ, , ι, , ς, , ) referred to activity engaged in by free men. Aristotle held that there were three basic activities of man: theoria, poiesis and praxis. There corresponded to these kinds of activity three types of knowledge: theoretical, to which the end goal was truth; poietical, to which the end goal was production; and practical, to which the end goal was action.