This course explores the relations between quantitative and qualitative approaches to volatility in finance and economics. Quantitative approaches to volatility are derived from expected utility and formal models of decision-making under uncertainty; behavioral finance and economics explore the qualitative dimension of "animal spirits" and why people don't follow the dictates of expected utility theory. Since volatility applies to quantitative phenomena such as stock prices and qualitative changes such as in affect, it provides a framework for the models of subjectivity in finance and economics.