Kritik der Urteilskraft
From 1985 to 1991 Tsang re-enrolled for the PhD program at HKU, this time in philosophy of religion, with the research topic of existential wonder. To place the topic in a historical context, his supervisor F.C.T. Moore introduced him to Kant's "Critique of Judgment" on the concept of the sublime. Eventually, he worked out a thesis on a new theory of the sublime in the tradition of Longinus, Burke and Kant, later published as "The Sublime: Groundwork towards a Theory" by the recommendation of Joseph A. Munitiz, then the Master of Campion Hall, Oxford.