In his critique of my book Heidegger and Marcuse, Jeff Kochan (2006) asserts that I am committed to the possibility of private knowledge, transcendent truths, and individualism. In this reply I argue that he has misinterpreted my analysis of the Challenger disaster and Marcuse’s work. Because I do not dismiss Roger Boisjoly’s doubts about the Challenger launch, Kochan believes that I have abandoned a social concept of knowledge for a reliance on the private knowledge of a single individual. In fact, (...) I consider Boisjoly’s observations just as social, if not as scientific, as the results of rigorous scientific study. Kochan’s reliance on a principle of symmetry derived from science studies to explain such politically charged technological controversies tends to mask the role of power and ideology in social life. Kochan interprets Marcuse as a failed Heideggerian who regresses from Heidegger’s social conception of human being to traditional individualism. I am accused of sharing this view. This interpretation overlooks the importance of the Hegelian–Marxist category of ‘real possibility’ in Marcuse’s work and so mistakes his critique of conformist politics for individualist romanticism. Marcuse always attempted to ground radical opposition in a community of struggle without abandoning the heritage of a long critical tradition. This view I willingly share. Keywords: Philosophy of technology; Principle of symmetry; Challenger disaster; Herbert Marcuse; Martin Heidegger; Knowledge . (shrink)