Tertiary qualities have been studied primarily by Gestalt psychologists. My aim in this article is to revisit the theoretical assumptions regarding tertiary qualities. I start from the Galilean distinction of the qualities of experience, the Lockean subdivision of qualities, the subjectivist definition in aesthetics and the theoretical contribution of Gestalt theory, to show the theoretical value of ‘tertiary qualities’ in the current context of experimental psychological research. I conclude that tertiary qualities are a crucial keyword for an experimental psychology based (...) on the primacy of perception. Such a perspective is in favour of a neo-Gestalt Experimental Phenomenology. (shrink)