Typical reactions: "Imperialists ... don't want to see a strong China ... don't be fooled" and "Greenspan's warning is for the benefit of the US (institutional investors)".

A third explanation is that the stock market is endowed with Chinese characteristics which make it immune to a crash (a colleague who has dabbled in stocks tells me that price/earnings ratios are not germane when it comes to Chinese shares). And that, like the economy, it has only one way to go - up.

An analyst quoted by Reuters said: "Compared to global markets, China is different. The market structure is unique."

The authorities clearly want to see a cooling down - in the economy, real estate and, especially, the stock market. But worryingly, many think that the government would not permit a crash. No way, a colleague sanguinely assured me.

By the same token, the government could have kept housing prices stable. Created jobs for all. Set up a welfare net for society. And provided free, universal health care.

The reality is that a market economy , even a socialist market economy, is a tough beast to tame.

The key words are laissez faire and caveat emptor. And no one should blame the government if they get burnt.

When Isaac Newton, in 1720, made a 100-percent profit on 7,000 pounds he invested in stocks, he is reported to have said: "I can calculate the motions of the heavenly bodies, but not the madness of people."

Wonder what he said when he went into the market at its peak and promptly lost 20,000 pounds.

That the law of gravity is true? Or irrational exuberance? Or madness?