Berkeley’s criticism of Locke’s distinction between primary and secondary qualities is a challenge to epistemologists. Do we experience a mind-independent reality, even though we do it with the help of senses bound to give us subjective experiences? Berkeley – or a straw man by that name (i.e. Berkeley without God) – played an important part as sparring partner for an influential development of Danish theoretical philosophy in the second half of the 20th century. The protagonists here are Peter Zinkernagel (1921–2003) and David Favrholdt (1931–2012). Zinkernagel held an extraordinary appointment as research fellow at the University of Copenhagen. Favrholdt was the founding father of the Philosophical Institute at Odense University (today: University of Southern Denmark). This essay focuses on the constructive moments in Zinkernagel’s alternative to immaterialism, being based on a distinction between perception and action, and on Favrholdt’s development of a reconstruction of the distinction between primary and secondary qualities.