San Jose Mercury News, Calif., Stocks.comment Column.

Byline: Scott Herhold

Apr. 12--One of the great ironies of the stock market -- and one reason why it's so hard to time -- is that you never know you've reached a bottom until it's well over. No one officially announces, "Ladies and gentlemen, this is it. You may now resume having fun."

But with the rallies in the Nasdaq index and the Dow Jones average this week and last, it's worth asking the question: Have we passed the bottom? Was Wednesday of last week the low ebb? Is the worst behind us?

In many ways, this is an irrational quest, like George Washington asking himself at the time whether Valley Forge was really the worst the Revolutionary War had to offer.

And it begs the question of what happens if you assume that a bottom has been …