ThisRedundancy chapterAptation exploresAdaptation the concept of redundancy within architectural design, challenging traditional deterministic views by introducing evolutionary principles. Historically, design has been perceived as a human-centric, goal-oriented process. However, this chapter posits that redundancy, variability, and diversity are crucial attributes of robust architectural systems, especially in times of global crises. By examining redundancy from an evolutionary biology perspective, the chapter highlights how traits initially evolved for one function can be repurposed, contributing to adaptability and resilience. This approach, termed “aptive design,” encompasses both deterministic and non-deterministic strategies, offering a broader understanding of creativity and functionality. Through case studies from Algiers, Naples, and other urban contexts, the chapter demonstrates how informal and vernacular practices, often seen as marginal, play a vital role in urban resilience. By embracing redundancy, architects can innovate in sustainable design, repurposing materials to create adaptable structures. This evolutionary perspective on design challenges the primacy of human intentionality, suggesting that architectural evolution, like biological evolution, thrives on redundancy and adaptability.