 Though intuitively powerful, the miracle argument is contestable in a number of ways. One skeptical response is to question the very need for an explanation of the success of science in the first place. For example, van Fraassen (1980: 40; see also Wray 2007, 2010) suggests that successful theories are analogous to well-adapted organisms—since only successful theories (organisms) survive, it is hardly surprising that our theories are successful, and therefore, there is no demand here for an explanation of success. It is not entirely clear, however, whether the evolutionary analogy is sufficient to dissolve the intuition behind the miracle argument. One might wonder, for instance, why a particular theory is successful (as opposed to why theories in general are successful), and the explanation sought may turn on specific features of the theory itself, including its descriptions of unobservables. Whether such explanations need be true, though, is a matter of debate. While most theories of explanation require that the explanans be true, pragmatic theories of explanation do not (van Fraassen 1980: ch. 5). More generally, any epistemology of science that does not accept one or more of the three dimensions of realism—commitment to a mind-independent world, literal semantics, and epistemic access to unobservables—will thereby present a putative reason for resisting the miracle argument. These positions are considered in  section 4.