 The fundamental powers account of strong emergence is consistent with a range of replies to the challenges noted in  section 4.1.  The first challenge asserts that strongly emergent features are “inexplicable”, insofar as they appear only in certain organized structures and could not be predicted in principle through the laws of basic physics applied to emergent-antecedent conditions. One reply is simply to observe that in the history of physics itself there is precedent for adding new fundamental laws to explain what previously recognized laws could not (e.g., electromagnetism and the weak nuclear force—see Wilson 2002). When determining the fundamenta of the natural world, we must go where the evidence leads. An alternative reply in line with the second variant of the previous paragraph denies the charge of inexplicability by supposing that emergent features are the product of micro-structural dispositions that, unlike those which are more or less continuously manifested, have structural triggering conditions. A Laplacian observer of the unfolding universe prior to the initial onset of such emergent features would have no inkling of there being such latent dispositions towards collective emergent effects. But they are as fundamental as the more generally manifested dispositions associated with such properties as mass and charge (O’Connor &amp; Wong 2005). And it might be contended that while it is rational to presume that the natural world is a causally unified totality, we cannot presume that it is causally uniform (O’Connor 2000: Ch.6).