 The Scope Question: Several authors doubt that Williamson’s theory successfully accounts for knowledge of metaphysical modality, particularly as opposed to causal-nomological modality. For example, Lowe (2012) argues that since counterfactual knowledge is strictly causal-nomological knowledge, Williamson’s theory may only explain the latter, and not knowledge of metaphysical modality. The idea is that Williamson can’t really explain how we know that water is necessarily H2O unless he explicitly brings in extra principles—e.g., essentialist principles (for further arguments to the same effect see, e.g., Deng 2016; Gregory 2017; Tahko 2012; and Thomasson 2021).