This document discusses uncertainty in pharmaceutical manufacturing and regulation. It notes that the current US pharmaceutical regulatory system underestimates the inherent complexity of making drugs. Recurring errors, shortages and warning letters serve as reminders that some of our assumptions are incorrect. Pharmaceutical regulatory science has evolved from chaos to continual improvement. The culture of an organization, with an emphasis on quality, anticipation of problems rather than reaction, and measurement to enable anticipation, is important to quality outcomes. Bias and "cognitive dissonance" can prevent admitting mistakes, while "anticipatory thinking" and understanding why certain approaches are taken can help progress quality.