How would a supply sided explain how reducing taxes would increase revenue?

The term “supply-side economics” is used in two different but related ways. Some use the term to refer to the fact that production (supply) underlies consumption and living standards. In the long run, our income levels reflect our ability to produce goods and services that people value. Higher income levels and living standards cannot be achieved without expansion in output. Virtually all economists accept this proposition and therefore are “supply siders.”