Pragmatic vindicatory genealogies provide both a cause and a rationale and can thus affect the space of reasons. But how far is the space of reasons affected by this kind of genealogical argument? What normative and evaluative implications do these arguments have? In this paper, I unpack this issue into three different sub-questions and explain what kinds of reasons they provide, for whom are these reasons, and for what. In relation to this final sub-question I argue, most importantly, that these (...) arguments are ambiguous about what they give us reasons for, meaning that they can be interpreted both as justifications for recognizing the normative standing of certain norms, values, and practices - and thus for living by them - and as excuses for those that do so. I illustrate this point by reference to the genealogical vindication of honour cultures, showing how the vindicatory argument can illuminate such case as one of excusing moral ignorance. Drawing on legal theory and moral philosophy, I show that different evaluative and normative implications hang on the result of the interpretation as either justification or excuse, and show that this ambiguity is a virtue rather than a limitation. (shrink)