Letters - A New Tax System Needs Fairness, Too - NYTimes.com Re "A Better Tax System (Instructions Included)," in which N. Gregory Mankiw listed four principles for tax reform (Economic View, Jan. 22): The column omitted a crucial "fifth" principle that is essential to meaningful change: the tax system must be and appear to be fair. This requires consideration of who bears the burden of taxation. Application of Professor Mankiw's principles, although representing sound economics, would likely shift the burden of taxation dramatically from wealthy and high-income individuals to middle- and lower-income taxpayers. His proposal to move toward consumption taxes is one example. Consequently, for such a system to reach the requisite degree of fairness, either tax rates must be raised on the wealthy, which could lower efficiency, or additional taxes - such as wealth, inheritance or estate taxes, which present fewer problems of economic efficiency - must be imposed or expanded. Without addressing fundamental fairness, any set of tax principles, however well intended from the perspective of economic efficiency, will inevitably fail to achieve a better tax system. Dennis B. Drapkin Dallas, Jan. 23