John Duns Scotus' (c. 1266-1308) understanding of theology as a practical science is based on the new meaning of practice. Practice is an elicited act of will (actus elicitus voluntatis), even in such a case when followed by a commanded act of will (actus imperatus voluntatis). There is a relation of priority and identity between a practical cognition that is based on intellect and practice that is a mater of will. Cognition is practical when it precedes an act of will. If will acts in agreement with this cognition, then will is correct. From the cognition of God as the object of theology and as the ultimate goal of man, conclusions or practical rules are derived that allow the existence of caused practice. The nature of the object of theology is the reason that allows the expansion of practical cognition towards practice. Practice is contingent since it is caused especially by will that is preceded by an act of intellect. According to Scotus, theoretical and practical sciences do not have a different object of inquiry - that is why practical science is not less noble. Unlike geometry, where instruction on triangles can be given without triangles being worthy of love, theology cannot be taught without God being an object of love. God is not only cognoscibile, but at the same time, operabile. The goal of theology is love towards God and love towards neighbor. Theology indicates ways of this love, indicates the rules for the correctness of loving. In simple words, love without rules is blind, and rules without love are empty.