 By using concepts of combinations of languages and combinations of logics, G. Schurz (see Schurz 1991; see also Schurz 1997) was able to state a generalized Hume’s thesis (GH); as observed in  subsection 4.1,  this treatment is in fact a fusion of two modal logics. In (GH) a mixed sentence \(\varphi\) is derived from a set of purely descriptive sentences (i.e., sentences free of \(\obcirc\)) only if \(\varphi\) is completely \(\obcirc\)-irrelevant (that is, predicates in \(\varphi\) within the scope of \(\obcirc\) can be replaced by other predicates salva valididate). Moreover, it is proven that (GH) holds in an alethic-deontic first-order logic \(\mathcal{L}\) if, and only if, \(\mathcal{L}\) can be axiomatized without bridge principles.