We discuss the case of Charlie Gard in light of the current philosophical debate around the epistemology of peer-disagreement, and consider to what extent, and in what ways, the philosophical debate can be used to elucidate messy and complicated real live cases and what these cases can, in turn, teach us about the philosophical framework. We argue that in order to be applicable to real-world cases of value disagreement, we should introduce the category of quasi peerhood. This peerhood obtains when agents recognize each other as epistemic peers even though they do not share evidence.

We argue for this point in two steps. Our negative upshot is that peer-disagreement about value questions is rarer than about factual questions, since matters of value are linked to an agent’s global outlook and this affects agents’ respective conception of evidence. It is often rationally permissible for agents to discard those they disagree with about value issues as peers, because both parties do not share the same evidence and sharing evidence is required to count someone as a peer.

Our positive upshot that we can learn from the philosophical debate that there are different kinds of disagreement and that peer-disagreement, if it obtains, puts rational pressure on agents to compromise. This is important for cases of disagreement between medical professionals about medical facts. Peer-disagreement, according to the standard notion of epistemic peerhood, is of limited relevance for value disagreement between parents and medical professionals, though. However, we argue that we should acknowledge quasi-peers. Quasi-peers do not share the same evidence, but they acknowledge that the other person has, roughly, equally good evidence, based on their respective conception of evidence. Disagreement with a quasi-peer puts rational pressure on you to compromise.