 There are three main libertarian options for understanding sourcehood or self-determination: non-causal libertarianism (Ginet 1990, 2008; McCann 1998; Lowe 2008; Goetz 2009; Pink 2017; Palmer 2021), event-causal libertarianism (Wiggins 1973; Kane 1996, 1999, 2011, 2016; Mele 1995, chs. 11–12; 2006, chs. 4–5; 2017; Ekstrom 2000, 2019; Clarke 2003, chs. 2–6; Franklin 2018), and agent-causal libertarianism (Reid 1788 [1969]; Chisholm 1966, 1976; Taylor 1966; O’Connor 2000; Clarke 1993; 1996; 2003, chs. 8–10; Griffith 2010; Steward 2012). Non-causal libertarians contend that exercises of the power of self-determination need not (or perhaps even cannot) be caused or causally structured. According to this view, we control our volition or choice simply in virtue of its being ours—its occurring in us. We do not exert a special kind of causality in bringing it about; instead, it is an intrinsically active event, intrinsically something we do. While there may be causal influences upon our choice, there need not be, and any such causal influence is wholly irrelevant to understanding why it occurs. Reasons provide an autonomous, non-causal form of explanation. Provided our choice is not wholly determined by prior factors, it is free and under our control simply in virtue of being ours. Non-causal views have failed to garner wide support among libertarians since, for many, self-determination seems to be an essentially causal notion (cf. Mele 2000 and Clarke 2003, ch. 2). This dispute hinges on the necessary conditions on the concept of causal power, and relatedly on whether power simpliciter admits causal and non-causal variants. For discussion, see O’Connor (2021).