 There is some scholarly dispute about the relationship between the four theses set out in the last four sentences of the preceding paragraph. Williams (2007) argues that the thesis about laws is explanatorily prior to some of the theses about rationality and content. Sider (2001) argues that the third thesis is a standalone part of Lewis’s theory. Schwarz (2014), however, argues that it isn’t even a part of Lewis’s theory. Weatherson (2003) endorses Sider’s view, but later Weatherson (2013) endorses Schwarz’s critique of Sider’s interpretation, while arguing that a qualified version of the third thesis can nevertheless be derived from the first two. (A version of Schwarz’s paper had been in circulation since 2006, so it well precedes Weatherson’s 2013 paper, despite the slightly later publication date.) Janssen-Lauret and MacBride (2020) respond to Schwarz, arguing that evidence from Lewis’s recently available correspondence supports the view that Lewis took naturalness to play a central role in determining the reference of individual words.