 Section 6 presents two versions of stability theories of laws in the special sciences, namely Lange’s (2000, 2002, 2005) stability theory in section 6.1, and Woodward &amp; Hitchcock’s (see EG1 and Hitchcock &amp; Woodward 2003, hereafter EG2) invariance theory in section 6.2. The common general idea of invariance or stability theories of laws is that the laws differ from merely accidental non-laws in virtue of their invariance or stability under counterfactual suppositions. According to this view, ceteris paribus or non-universal laws differ from universal laws in degree, not in kind: universal laws hold under all counterfactual suppositions while ceteris paribus or non-universal laws merely hold for a limited range of suppositions.