ABSTRACT
For the principles which underlie the rejection of Isomorphism-Requirement are ones which the phenomenalist can further exploit. Indeed, they are principles which, given the acceptance of a physical reality, will oblige us to accept, almost in full, the phenomenalist’s account of its sustainment. The structure of the physical world need not be exemplified by the external reality, and it will not be exemplified if the functional geometry of the external component differs from its intrinsic geometry. Nomological deviance is not the only organizational factor which undermines isomorphism. Just as the structure of the physical reality conceals any nomological deviance in the external reality which underlies it, so also it conceals distinctions which are nomologically irrelevant. We can see that there are at least two general ways in which the physical reality can fail to be isomorphic with the external reality which underlies it.
