Legitimate Conclusions of Wigner’s Friend Paradox Seyyed Bahram Borgheai Abstract Wigner’s Friend paradox is an argument which Wigner has used to illustrate the causal role of consciousness in the measurement problem. In this paper, we first look in depth in his stated pre-suppositions and will introduce some more implicit ones which are not mentioned explicitly by Wigner. In the analysis of the argument, it will be illustrated that Wigner is not successful in reaching his goal and therefore the causal role of consciousness cannot be legitimately entailed from the paradox. Rather, one of the most important conclusions of the paradox is the communicability of conscious observation knowledge for others (conscious observers) for which one of the pre-suppositions should be eliminated. This may result in inter-subjectivity which can be a host of future investigation. Moreover, another legitimate way of resolving the paradox is to reject one of implicit pre-supposition which is the completeness of standard quantum mechanics about some aspects of conscious related events. This is the main conclusion of the paradox which can be rehearsed from different aspects. Finally, after reviewing some objections to the paradox and also some other solutions to it, a new formulation of the paradox will be presented with some modifications over the presuppositions. Introduction The measurement problem is one of the most controversial concerns in philosophy of physics. . On one hand we have linear equation predicting the evolving states of physical system resulting in superposition states 1 . On the other hand, when we make the measurement the state of a system nonlinearly goes to one definite state. Therefore what we have according to the equations of QM is not sufficient to explain this reduction of states. There are different proposed solutions to this problem. Some are known as no- collapse theories as many-worlds interpretations and its extensions which are multi- minded and also single-minded theory. Moreover we have creation at observation claim, 1 When the state of the system is not one of the eigenstates of the system.