This paper investigates the possibility that the instrumentally rational nature of late-modernity restricts product design from contributing substantively to sustainability as this form of rationality views technological artefacts in neutral terms and discourages reflection upon the “ends” that technologies serve. The philosophical approach of postphenomenology is proposed as a lens for supporting product design students to address sustainability more substantively as postphenomenology emphasises the “ends” that technologies serve by understanding technologies as being active mediators of the relations people have with their world. A practice-based design research method is introduced, which aims to support design students to engage with postphenomenology through the activity of designing. This method involves the creation of conceptual objects that critique technologies and embody alternate values to those that typically drive technological development in late-modernity. Finally, distinctive aspects of the designing process associated with this method are identified that support students to address sustainability in a more substantive manner than late-modernity encourages.