This chapter critically examines some of the popular theoretical justifications that have hitherto been postulated as explanations for the existence of intellectual property rights in general and patent rights in particular. The focus here is limited to the Lockean theory, the Hegelian theory, the utilitarian theory, and the regulatory theory. The chapter is structured into four sections. Sections 2.2 and 2.3 examine the Lockean and Hegelian theories, respectively, while Sections 2.4 and 2.5 focus on the utilitarian and regulatory theories, respectively. The chapter concludes with the view that the regulatory theory of intellectual property is the only theory that adopts a broad socio-centric approach. Thus, any developing country that seeks to preserve its patent policy space and secure access to medicines for its citizens should treat intellectual property law (including patent law) as an instrument that regulates the grant of exclusive rights to creators.