 These examples are controversial. For any given mathematical claim whose truth-value is unknown, one could hold that it is only our cognitive limitations that have prevented us from establishing or refuting the statement, and that the question could be decided by ideal reasoning (so that the truth of the matter is a priori). Alternatively, it may be held that the truth-value of the mathematical statement is indeterminate. (Perhaps our practices do not completely determine the references of all the terms used in the mathematical claim). The same two options are available in the case of metaphysical principles. Alternatively, one may argue that the relevant metaphysical theses are merely contingent (see, e.g., Cameron 2007). Necessitarianism about the natural laws is highly controversial and may simply be denied. And in response to (iv), one may deny that the physical truths metaphysically necessitate the mental truths (Chalmers 1996), or one may hold that the mental truths can be derived from the physical ones by a priori reasoning (Jackson 1998).