Reason and Freedom of Choice

One of Kant's controversial theses is that humans possess a freedom by which they can wittingly disobey Reason, a thesis which, consequently, grounds the existence of 'Evil' in such 'freedom of choice'.  He, thus, opposes Aristotle and Spinoza, who contend that malfeasance always entails an intellectual error of some kind.  The closest that Kant approaches to a proof of the existence of that faculty begins with the proposition that Deservedness is a Rational concept, so that the capacity, entailed by that concept, to choose Vice as well as Virtue, is, likewise, a Rational concept.  However, that proof betrays itself.  For, the presumed Rationality of Deservedness presupposes that of individual Happiness, one of its components.  But, explicitly and implicitly, in its formulation, the principle of Pure Practical Reason is indifferent, at best, to any concept of Happiness.  Hence, the ascription of a concept of 'freedom of choice' to Reason constitutes an intellectual error.  Furthermore, that the concept of Deservedness grounds his subsequent proof of the 'existence of God', encourages the diagnosis that Kant's thesis of the existence of a 'freedom of choice' is the product of a vestigial irrational Theological prejudice.