This lecture discusses the importance of science advice in government decision-making, focusing on the role of knowledge brokers in providing interdisciplinary scientific support during the COVID-19 pandemic. It explores the challenges faced by science advisors in communicating complex scientific issues to policymakers and the public, emphasizing the need for trust, mutual understanding, and clear roles. The lecture also delves into the ethical and legal aspects of public health interventions, highlighting the consequences of different policy measures on society and the economy. Additionally, it touches upon the concept of leaving planetary boundaries and the impact of human activities on the environment.