Cutting taxes on the upper class means more money for the upper class. Since the upper class invests money(which is one of the reasons they are in the upper class), that is probably where the extra money will go. By investing in businesses, this puts more money in the businesses and in the economy. With businesses doing well from the extra capital and the healthy economy, the business will perform better. With the businesses performing better, this promotes the idea of raising wages. When the economy is healthy everyone does better. Also with a healthy economy, there is healthy inflation. Inflation is actually good for an economy(that is an explanation for another time). With the business performing good and inflation involved, this produces higher wages(and many of the other great stuff in a good economy).