If the DOW got to 5,000, the average P/E ratio for DOW 30 stocks would be under 9. That's using today's earnings. So I guess he's taking into account future earnings, where the company's P/E would be higher.
The S&P has an average P/E of around 36.00 right now. So, technically speaking, it should be trading around 450 if you take into account the historical average P/E ratio for most companies. If earnings fell further, the P/E would be even more inflated and the S&P would have to fall below 400 to catch up with "historic values."
This doesn't even scratch the surface with the impending 100 trillion dollar derivative disaster that may come within the next 5 years.
aphie