Furs and vacations are examples of the legitimate economy. Either a sales tax or a income tax will capture that.
Drug deals and prostitution are examples of the underground economy. Neither tax system can capture that.
"Furs and vacations are examples of the legitimate economy. Either a sales tax or a income tax will capture that."
Please explain to me how an income tax captures the taxes owed by a member of the underground economy when they buy furs or take a vacation.