 Zhang Dongsun maintained that a pure form of either proposition did not exist in reality. The absence of distinctions between analytic and synthetic propositions implies the abolition of the demarcation between (posterior) experience and (a priori) knowledge and, consequently, between metaphysics and the (natural) sciences. Most Chinese scholars from the latter half of the 20th century argued that the reason for this demarcation was to be found in the fact that metaphysics only referred to the formal regulation of experiences, while science also explained their contents (Feng 1986: 166–167). However, some recent Chinese epistemological theories likewise reject the reasoning behind such demarcations and criticize the existence or methods of the discourses based upon them. For them, both science and metaphysics explain experience; in addition, both represent a formal kind of explanation. Hence, Zhang Dongsun transcended the boundary between science and metaphysics, while Feng was convinced that it was insuperable. In Zhang Dongsun’s view, the only difference between metaphysics and science lay in the fact that science applied the postulate of relations, while metaphysics applied the postulates of being and existence (Zhang 2002: 77).