Higher education has often been accused of its anti-social character, represented by the metaphor of the 'ivory tower'. However, the idea of the pursuit of knowledge per se, which is associated with the ivory tower, has not been widely recognized as a public ideal of higher education. In this study, by drawing on the 20th-century British educational philosopher Paul H. Hirst's theory of liberal education, I revisit and re-evaluate the Newmanian idea of pursuit of knowledge as an end itself as a public ideal for higher education. I argue that the public criteria provided by discipline-rooted knowledge are among the criteria that are most able to define and legitimise higher education. These public criteria are compatible with the distinctive nature of higher education, which is essentially aimed at adult citizens and linked to research as the creation of knowledge, and can even serve to legitimise the cognitive structure of the society.