at deviations from interconnectivity and standardization are sometimes justified and that it can be difficult, if not impossible, to determine whether a particular deviation is justified. When that is the case, the usual policy response is to allow experimentation with different business practices and to place on those who would oppose such practices the burden to demonstrate some adverse effect on competition. Erecting a presumption against discriminatory access and forcing owners to jus- tify any deviations would have the effect of foreclosing practices that are ambiguous or for which evidence of actual market performance is lacking. This would have the unfortunate effect of preventing the development of network diversity even if entry by diversified network providers would be welfare-enhancing. Given the difficulties in forecasting the impact of technological change and in predicting which business models will ultimately prove successful, the humility inherent in a more restrained approach provides critical breathing room for the experimentation upon which the innovative process depends. Although the difference between the network diversity approach and the more modest, ex post versions of network neutrality at first glance may appear to be nothing more than a difference in emphasis or a shift in the burden of proof, allowing practices to go forward until they are proven harmful has the important consequence of permitting experimentation with ambiguous practices that would be foreclosed under a presumption of nondiscrimination. Even if competition were not sufficiently robust to prevent network owners from undertaking anticompetitive conduct, it is extremely unlikely that the type of blanket approach to nondiscrimination favored by network neutrality proponents would represent the proper policy response. Should a local telephone company attempt to protect its core business by blocking its DSL customers from using VoIP or a cable modem provider attempt to protect its core cable television business by prohibitin