 Crucial to Roca-Royes’s account is the notion of an epistemic counterpart, whereby \(a\) is an epistemic counterpart of \(b\) just in case there’s a point in each of \(a\)’s and \(b\)’s timelines where they are relevantly similar (e.g., made from the same kind of materials) and, in virtue of this, what has happened to a informs us of what could happen to \(b\). In the example: Twin-Messy’s breaking informs us that Messy can break. Premise  (RR4)  plays a major role in Roca-Royes’ account. She calls the knowledge at stake here nomic-like (2017: 229) and clarifies that it is supported inductively, since it heavily relies on the uniformity of nature.