  Whereas Bergmann focuses on lacking a positive reason for representativeness, Howard-Snyder focuses on the presence of doubt concerning representativeness. Here, Howard-Snyder's approach is more consonant with Wykstra's, since Wykstra's defense of Obscurity would establish AT1 (whereas it provides only weak support for ST1). An advantage of AT1 is that it, unlike ST1, does not require the Representativeness Principle in order to be effective. For it is plausible that the lemma relies on something like the following principle.