 The Circularity Question: Several authors have critically pointed out that Williamson’s method of counterfactual evaluation appears to rely on pre-existing knowledge of what Williamson sometimes calls “constitutive facts”. These are most commonly taken as facts about the essence of objects. Now, if we take essentialist facts to be modal in that the essence of something is the way it must be, this reliance is problematic for it might make Williamson’s epistemology of modality circular (see, e.g., Boghossian 2011; Tahko 2012; Roca-Royes 2011b). In response, Williamson might contend that his account is not meant to reduce modal knowledge to counterfactual knowledge, but rather only to clarify how the one may be a special case or byproduct of the other (Morato 2019). Furthermore, Williamson might hold that subjects need not have explicit modal knowledge in order to carry out their counterfactual evaluations, namely they need not know that some facts are necessary. Instead, subjects only need to be somehow reliably sensitive to those facts (Yli-Vakkuri 2013; for discussion see Vaidya &amp; Wallner 2021).