About the flat tax, it has several problems. A common argument against it is that the marginal value of money declines with the amount of income (an extra $100 means a lot more to a family earning $20k a year than to a family earning $200k). As a result, a true flat tax would be detrimental to the poor, as a family living on $20k-40k a year will have a hard time if they must pay 20% (or whatever the rate is decided to be) of their income in taxes. Due to this glaring problem, proponents of the flat tax usually never support a true flat tax and tend to favor some kind of deduction. However, even with a deduction, a flat tax removes tax burden from the rich and decreases tax revenue, which may not be desirable given the US's propensity towards deficit spending.
Another issue is that a flat tax doesn't make the tax system much simpler, unless corporate taxes, dividend taxes, estate tax, etc. are also removed. However, removing those taxes will make the overall tax system regressive and the very rich (such as CEOs) can avoid most taxes by taking stock options as their payment. The resulting income and wealth equality might become unimaginably high.
Regarding capitalism, few people would be willing to accept a purely capitalist society (not that it's possible in the first place). If you think about it, free markets and perfect competition do not exist. Most industries are monopolies (utilities), oligopolies (communications, automobiles, health insurance), or monopolistic (clothing, restaurants). As a result, the "free market" is actually not as responsive/cheap/efficiet as it is portrayed to be. In fact, markets tend toward conglomeration or horizontal integration. Why else would there be so much "trust-busting" during the Roosevelt/Taft era?
Furthermore, free markets cannot work unless buyers are informed and can make informed decisions about a product. For various reasons, complete knowledge on the part of buyers has never been possible. As a result, regulatory agencies such as the FDA are needed to prevent exploitation of the buyers. For a not-exactly-unbiased, but exciting, account of what happened before regulatory agencies, why not take a look at The Jungle by Upton Sinclair?
Nevertheless, most people agree capitalism is a good system, as long as regulations and social programs are in place. Your friend is a bit in the minority.
Edited by lowellite, 25 August 2010 - 08:01 AM.