Experts in tax policy discuss the pros and cons of income-based versus consumption-based taxation in the context of fundamental tax reform. They explore the impact of tax reform on businesses, international taxation issues, and individual behavioral responses. The goal is to identify critical questions and assess whether the answers are known, unknown, or unknowable. Key findings include the need for careful consideration of the transition to a consumption-based tax, the effects on businesses' investment behavior, and the importance of understanding individual behavioral responses to tax reform.