 His most important philosophical works include Science and Philosophy (), Outlook on Life (), Essays on Philosophy (), Psychoanalysis (), Moral Philosophy (), Philosophy (), Modern Ethics (), Modern Philosophy (), Value Philosophy (), Epistemology (), A new Formulation of Pluralistic Epistemology (), What is Philosophy (), Knowledge and Culture (), Thought and Society () and Rationality and Democracy ().Pluralistic epistemology represents the core of Zhang's philosophical system.It is derived from a revised version of Kantian philosophy.