Sustainable design is an approach that seeks to adopt an ethic of the future, where the vision of the solutions is based on a temporal and spatial perspective that is predominantly long-term and global. Design is characterized by its projective and ambivalent nature, and therefore a conscious effort to anticipate the outcomes of design intentions is crucial. Consequently, all design is inherently laden with uncertainty, doubt, and specifically in some technology-driven design projects - contradictions and controversies. Typically, such uncertainties and contradictions are not considered during the initial phase, since the main goal at this phase is to simplify the problem, and therefore these anomalies are often omitted, as they are seen to be outside the boundaries of the design problem. How can designers consider the uncertainties and contradictions during conceptualization, as well as consider the benefits resulting from their design proposals? Designers in their sustainable design practice must consider (1) the multiple objectives and criteria; (2) the multiple users and user preferences; (3) the multiple design alternatives; (4) the complex changing global situation; and (5) the knowledge from the various disciplines comprising the design project. A collective systems thinking approach to design addresses these concerns. Consequently, the theoretical basis of the precautionary principle is directly in line with this approach to design. This presentation will discuss the epistemological and practical implications of the precautionary principle for design in this context.