Advances in artificial intelligence (AI) are a double-edged sword. On the one hand, they may increase economic growth as AI augments our ability to innovate. On the other hand, many experts worry that these advances entail existential risk: creating a superintelligence misaligned with human values could lead to catastrophic outcomes, even possibly human extinction. This paper considers the optimal use of AI technology in the presence of these opportunities and risks. Under what conditions should we continue the rapid progress of AI, and under what conditions should we stop?