In classical philosophical terms, it is very important to distinguish three domains of human activity: theoretical reason, which investigates the truth of contingent events as well as necessary truths; practical reason, which determines whether a prospective course of action is worth pursuing; and productive or technical reason, which attempts to find the best means for a given end. Aristotle viewed philosophical activity as the highest activity of the human being and gave pride of place to metaphysics or wisdom. Since Descartes practical judgment and reasoning have been treated with less respect because of the demand for greater certainty and an infallible method to justify beliefs.