Chisholm's Paradox in Action Deontic Logics Pietro Pasotti Abstract: The thesis focuses on Chisholm's paradox and offers a philosophical comparative analysis using three logical frameworks in which the paradox can be formalised. Chapter 1 considers Standard Deontic Logic and tracks down the causes of its well-known inadequacies in copying with contrary-to-duty obligations to the back of expressive power concerning time, preference orders and action. Consequently in chapter 2 we follow J-J.Ch. Meyer in giving an action-based Propositional Dynamic Deontic Logic (PDeL) analysis of Chisholm's paradox. Finally, acknowledging that the PDeL analysis has many open issues, we move to the seeing-to-it-that (stit) framework exemplified by one of the main existing proposals from P. Bartha. Finally, we show that Bartha's solution is problematic and try to fix it by adopting a vairant of J. Broersen's temporal next-state stit. In this logic, under some assumptinos, many deontic paradoxes including Chisholm's paradox are avoided.