Sustaining the open society: resources from Popperian science

Abstract Open society liberalism has experienced a revival in the 21st century, prominently led by Gerald Gaus. Despite its growing popularity, however, the boundaries of whose moral and political perspectives ought to be included remain underspecified. Its most famous early defender, Popper, thought that unreasonable individuals, such as those who hold to beliefs dogmatically, should be excluded from the open society. A belief not unusual among other liberal theorists. However, what these open society theorists miss is a possible underutilized resource that comes from Popper’s philosophy of science. Within science, Popper believed that dogmatic individuals were necessary and important for scientific progress. Using this resource, I argue that Popper himself and other open society theorists in general should be more inclusive and tolerant of closed society individuals, including dogmatic religious individuals, because they allow for liberal progress and the sustainment of the open society.