 But the fact that unrestricted quantification is relatively uncommon is no reason to doubt it is attainable in certain contexts. Unfortunately, many philosophers have recently doubted that genuinely unrestricted quantification is even coherent, much less  attainable.[21]  Note that these philosophers face at least two preliminary challenges, both of which are forcefully pressed by Williamson (2003). First, they face the question of what to make of the prospects of ontological inquiry without unrestricted generality. How should we formulate substantive ontological positions such as nominalism, if we cannot hope to quantify over all objects at once? The second challenge for the skeptics is to state their own position. To the extent to which the thesis that we cannot quantify over everything appears to entail that there is something over which cannot quantify, skeptics seem to find themselves in a bind by inadvertently quantifying over what, by their own lights, lies beyond a legitimate domain of  quantification.[22]  Typical responses to each problem involve a surrogate for unrestricted generality in the form of either schematic generality or the use of certain modal operators to simulate quantification over a series of ever more comprehensive domains of  quantification.[23]