When Mehdi Haeri Yazdi, in his book Wisdom and Government, intends to articulate the theory of citizens’ joint ownership, he grounds his argument in practical reason. Over the years, various critiques have been presented regarding his view of government and his proposal of a model based on the agency (wikālat) of the sage in contrast to both social contract theory and the doctrine of guardianship of the jurist (wilāyat al-faqīh). These critiques have largely emerged from juridical, legal, or political perspectives. This article, adopting a philosophical approach, first offers a new account of the oughts of practical reason in Haeri Yazdi’s thought. It then examines the methodological soundness of the theory of joint ownership, which is based on the application of practical reason, while remaining faithful to the author’s own principles and method. The findings indicate that although Haeri Yazdi initially provides a detailed account of the relation between “is” and “ought” and seeks to secure the foundations for reliance on practical reason, his following effort results in a certain inconsistency in the application of practical reason. Moreover, the author has based his theory on presuppositions that themselves are open to critical scrutiny.