The Laffer Curve is just common sense.
Originally Posted by joe bloe
Actually, Joe, the Laffer Curve is NOT "just common sense".
It is solid mathematics.
The Laffer Curve is a trivial application of Rolle's Theorem from elementary calculus. Loosely stated, Rolle's Theorem says that, for ANY continuous function defined between two points a and b, whose value is zero at both a and b, there will be at least one point c in between them at which the slope of the function is zero.
This is stated, and proved, in the first couple of weeks of first semester freshman calculus. It is usually presented as a critical lemma, proved in the course of proving the Mean Value Theorem. (The Mean Value Theorem is what you get when you do a simple change of value on Rolle's Theorem.)
Laffer, in one of the earliest papers on the Laffer Curve, himself cites Rolle's Theorem as its basis.
The key point of the Laffer Curve is not, as the liberals like to think, that there is an OPTIMUM tax rate, that maximizes taxpayer ripoff, but rather that raising tax rates at SOME point will hit diminishing returns. This point is absolute anathema to liberals: they desperately want and need to believe that tax rates can be raised forever.
It is not necessary to assume that the second zero point is at 100% tax. Consider what happens if you set the tax rate at, say, 500%. Very few people are going to work, and pay taxes, if they have to pay all that they earn, and 4x as much to boot, for the privilege of working. (Special cases of this scenario occur frequently: look what happens when someone has to choose between making a few dollars more, or keeping his welfare medical coverage.)