Tertiary qualities, from Galileo to Gestalt Psychology

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 qua- lities, 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.