High taxes slow down economic growth. Higher taxes in almost all cases decrease growth and in the best scenario just have no influence this is not just an opinion there are 26 studies that prove this:

http://taxfoundation.org/article/what-evidence-taxes-and-growth





There is a consensus among economists that higher taxes lead to less growth. There has been a survey among top economists in 2012 whether tax cuts in the US would lead to economic growth only 8% disagreed or strongly disagreed with this statement:

http://www.igmchicago.org/surveys/laffer-curve





It is quite clear higher taxes are bad for growth from a scientific view point. There are three taxes that are especially bad:

Corporate income taxes

Personal income taxes

Capital gains tax





Taxes on consumption are less problematic. Therefore it should be the first goal to decrease or abolish the three especially bad taxes, while shifting to taxes on consumption.

The next time when you talk with liberals about science tell them what the science says about taxes.