I found Brown and Hands' thoughtful comment on my article, Expand? ing the Scope of the Neoclassical Vision, stimulating, and I appreciate the opportunity to reply. Brown and Hands make three points about my presentation: 1. First, falsification is never as easy as Evensky implies. 2. Second, Evensky's contention that nonfalsification theories are tautol? ogies is simply not true. 3. Is such a refinement of terminology [clarifying the concepts of rent and profit] sufficient to integrate institutional non-neutrality into neo? classical economics. I will address each point in turn. First, falsification is never as easy as Evensky implies. If I implied that, as a practical matter, falsification is easy, then I am guilty as charged. That implication was not my intent, for I am fully aware of the difficulties, if not impossibility, of designing a crucial experiment that will unequivocally test a theory. My point with respect to falsifiability is that a theory should, at least conceptually, have the capacity to be wrong. This brings me to my assumption/presumption distinction. I thank Brown and Hands for focusing my attention on my use of those concepts, for they do need clarification. An assumption specifies the conditions surrounding the analytical focus while a presumption is a vague, impressionistic view of the conditions surrounding that focus. As Brown and Hands correctly point out, an assumption can be probabilistic in a formal sense. The distinction between assumption and presumption is that the former is fixed and the latter is malleable ? subject to ad hoc change. Assumptions can and should be made explicit because they precisely specify the conditions to be taken as given. Presumptions are invariably implicit. One never reads We will presume ... in the specification of a theoretical framework because to say one is presuming is to admit to a lack of clarity in the theory's foundation. A presumption has the same effect as a vague definition when built into a theory's foundation. Both make that foundation mobile. As a result, a theory built on such a foundation can always adjust, ad hoc, to fit the evidence. Such a theory is not conceptually falsifiable. The point of my article is that neoclassical theory suffers from just such a malady. It presumes the neutral? ity of institutions and adjusts to obvious contradictions on an ad hoc basis.