Ontology ultimately determines who is able to participate in framing beliefs and shapes boundaries with society’s perception of the economy.

It is in the nature of such a constitutional framework that it determines the boundaries of a discipline or a line of research. Among the ontological or metaphysical core principles of economics, including constitutional economics, Buchanan lists individual autonomy, rationality of choice, and spontaneous market coordination. 'Unless those who would be participants in the scientific dialogue are willing to locate the exercise in the choice calculus of individuals, there can be no departure from the starting gate . .. The principle of spontaneous coordination of the market is the principle of our discipline' (Buchanan 1991, pp. 14, 22). Buchanan thus takes such principles as defining the boundaries of a research field or programme. Such ontological principles have social consequences: they effectively help identify the genuine participants in a programme and exclude others as non-participants. 'There is simply no common basis for scientific argument, and ultimately agreement, with those who choose to perceive social interaction either in purely conflic-tual or purely idealistic visions. These visions are, indeed, alternative "windows" on the world' (p. 18). Legitimate membership in the conversations of the economics profession thus requires that the world is being viewed through shared ontological 'windows'. Another feature characteristically ascribed to the fundamental commitments is implicitness. The constitutional world view they work with or the ontological windows through which they view the world are articulated by practising economists themselves only seldom and incom-pletely, if at all, such explicit articulation is characteristically not regarded as one their preoccupations qua economists. In contrast, making explicit what tends to be implicit is exactly the preoccupation of this book. Buchanan says that 'the process through which individuals choose among such windows remains mysterious' (p. 18). It is one purpose of this book to start demystifying the process of choosing such ontological windows. It is a prerequisite of this demystification that we understand what those windows are like. One has to start looking at the ontological windows instead of merely looking through them. This is also acknowledged by Buchanan in his remark about the insiders and out-siders: "External intellectual challenges to the whole enterprise tend to be directed at these elements in the core of the program. The ongoing research within the constraints can, of course, proceed without concern for these external criticisms, but practitioners need to be aware of the core-imposed limits on the persuasive potential of the internalized analytical exercise' (p. 14). It is a purpose of this volume to help practitioners in economics be aware of the core-imposed limits' of what they can successfully do as such practitioners. A more ambitious goal would be to try to help economists to make well-argued constitutional choices, that is, reasoned choices of the constitutional framework within which they do their work, or of the windows through which they view the world - or at least help them to be aware of that larger framework and to design arguments for the constitution they have ended up working with, whether as a matter of choice or perhaps as a matter of some path-dependent academic process. The possibility of constitutional choice implies that ontological constitutions are not fixed, that in principle they can be changed at will. Constitutional change may also - and often does - occur without much reflection; as Wittgenstein puts it, the riverbed within which our thought flows can itself change in response to the flow of thought (Wittgenstein 1969, $97).