How reasonable is it to suppose that this extra requirement is usually fulfilled? Not at all, presumably. To believe otherwise, we must assume some sort of privilege on our part to the effect that when we consider possible explanations of the data, we are somehow predisposed to hit, inter alia, upon the absolutely best explanation of those data. After all, hardly ever will we have considered, or will it even be possible to consider, all potential explanations. As van Fraassen (1989, 144) points