Is Quantum Mechanics Universal? EWF Experiments and Non Absoluteness of Events

Abstract: Extended Wigner-type experiments reveal a fundamental tension between the universality of quantum mechanics, the absoluteness of observed events, and the structure of physical reality. While recent no-go theorems suggest that these assumptions cannot be jointly maintained, their interpretation remains unclear. In particular, the claim that events are not absolute is often left at the level of an interpretive slogan, without a precise conceptual formulation. In this paper, we analyse the conceptual structure underlying these results and show that the non-absoluteness of events requires a precise formulation in order to avoid ambiguity. We argue that many existing approaches fail to provide such a formulation, either by implicitly reintroducing observer-independent structure or by leaving key notions underdetermined. Within this framework, Convivial Solipsism offers a coherent and fully articulated account of non-absolute events, preserving the universality of quantum mechanics while avoiding the need for a global viewpoint. We show in particular that this approach resolves the apparent conflict between perspectival outcomes and scientific intersubjectivity. These results suggest that scientific objectivity does not rely on observer-independent facts, but on the internal coherence of perspectival structures.