Using Generative AI to Grapple with the Not-Yet-Known

This empirical paper presents the Critical Participatory Co-Design (CPC) Method, with preliminary research findings based on the case study of a workshop. It explores the potential of human-AI co-creation to facilitate the participation of communities in envisioning responsible technology design and deployment. On the methodological side, the paper describes this method that combines the steps of Critical Making, Participatory Design's paper prototyping for scenario building, the creation of shared languages, and generative AI through a device called Street2Paradise_ for speculative future visions. On the empirical side, an experimental case study conducted with urban designers is presented to investigate the method's validity, its capability to contribute to critical thinking and reflexivity, and how it can include communities in large-scale technology development. The paper proposes rigorous approaches to understanding the value of the CPC method. It also opens up a broader problem space for the future: whether such methods can empower communities to change the course of large-scale digital transformations. The paper contributes to the growing body of HCI and CSCW literature on technology-assisted participatory and reflexive methods for equitable sociotechnical futures.